English language

How to pronounce potassium hydrogen carbonate in English?

Full Transcript

where is the s-block in the periodic
table it's the first two columns or
groups of the periodic table this region
of the periodic table is sometimes
referred to as the s-block because all
the outermost electrons of these
elements will occupy the s orbital there
are two columns in the S lock because an
S orbital can hold a maximum of two
electrons the metals in Group one
include lithium sodium potassium
rubidium cesium and francium note that
hydrogen is not included here as it
typically does not exhibit metallic
behavior
here are some interesting facts about
the group one metals lithium is the most
abundant member of the family francium
is radioactive and it's longest-lived
isotope has a half-life of only 21
minutes
do you know the origin of the group name
alkali metals
when Group one metals react with water
they produce hydroxide or H ions
hydroxide ions in water produce basic or
alkaline solutions in the presence of
phenolphthalein an indicator the
solution will turn pink as hydroxide
ions formed react with phenolphthalein
before we move on let's review the
electron configurations of the alkali
metals lithium with only three electrons
has a configuration of 1s2 2s1
sodium with eleven electrons has an
electron configuration of 1s2 2s2 2p6
3s1 similarly for potassium the electron
configuration is 1s2 2s2 2p6 3s2 3p6 4s2
all have something in common
all the electron configurations end as
s1 this is emphasized when the electron
configurations are written in noble gas
notation all the alkali metals have
electron configurations that end as n s
1 where n is the highest occupied
principle energy level with such similar
electron configurations it's no surprise
that the alkali metals have some very
similar physical and chemical properties
we'll explore this further as we go
through the module
the group one metals are the most
reactive metals known in sight they are
so reactive that they are never found in
the elemental state in nature only in
compounds since the old react with water
they must be stored under oil as shown
in the illustration they will even react
with water in the air the alkali metals
are all shiny and silvery in appearance
they are so soft that they can be cut
with the table knife which is often
surprising to students like all metals
they are good conductors of both heat
and electricity as shown in the diagram
they will form a Down oxide layer on
their outer surface when exposed to air
this layer can easily be cut away to
reveal the shiny interior
recall that the alkali metals all have
electron configurations ending as s1
the single balance electron for each of
these elements is relatively loosely
attracted to the nucleus if this sole
valence electron is lost then the
resulting ion is isoelectronic with the
preceding noble gas elements that is
having the same number of electrons as
the preceding noble gas does the typical
ion formed by alkali metal is a cation
with the charge of +1
you
let's go on and review some periodic
properties as they relate to alkali
metals as you consider the group of 1
elements from top to bottom atomic
radius increases this can be explained
because as you move down the group there
is increase in the number of shells and
therefore the atomic radii increases
the cations that form are in all cases
smaller than the parent atom since there
are fewer electrons there are fewer
electron-electron repulsions and so the
radius is smaller for the cation for
essentially the same reasons as we
discussed with atomic radius the cation
radii for the group one metals increased
from the top to the bottom of the group
as shown in the graphic moving from left
to right across the period the alkali
metals have the largest atomic radius of
any element in the period
try to answer this question on your own
before you proceed we're in the periodic
table would you expect to find elements
with the largest atomic radii
the largest atoms are found in the lower
left-hand corner of the periodic table
cesium and francium
recall that ionization energy is defined
as the energy required to remove the
outermost electron from an isolated gas
phase atom since the valence electrons
are significantly shielded from the
nuclear charge the ionization energies
of the alkali metals are relatively low
in general
ionization energies decrease down a
column
and the alkali metals are no exception
assuming the graph
enthalpy of salvation or hydration
energy is the amount of energy released
or absorbed when one mole of an ion is
dissolved in a large amount of water in
general as the ionic radii get larger
hydration energy decreases and so the
enthalpy of hydration decreases from
lithium to cesium one dassault is that
lithium songs
unlike the soles of the other alkali
metals often form high traits such as
lithium chloride dihydrate
how can we test for the presence of
alkali metals in a particular sample
what simple and qualitative test is the
flame test
if a small amount of a metal salt is
held in a flame
characteristic color changes can be
observed
due to the movement of electrons
electrons get excited to higher energy
levels from the heat of the flame and
emit energy as light as they return to
their ground state
folder quantitative test
atomic absorptions spectrometry can be
used based on the same fundamental
principles
let's look at the result of some flame
tests lithium gives a cheerful
candy-apple red color this yellow color
is characteristic of sodium you may have
observed it if a boiling salt water
sample spills over when cooking on a gas
stove potassium flame tests emit a lilac
colored flame
you
let's apply our knowledge to a problem
an explosion occurred in a chemical
storage tank at Acme chemical company an
employee why filing a claim for workers
compensation for injuries states that
the potassium nitrate being stored in
the tank must have been responsible for
the green flames he observed is the
employee being truthful
we just learned that the presence of
potassium gives a lilac flame
therefore we must conclude that the
employee is not being truthful
let's discuss some chemical properties
of the alkali metals starting with their
reactions with oxygen the own react
vigorously with oxygen they don't all
form the same kinds of oxide still
lithium reacts with oxygen to form a
simple oxide li2 Oh sodium forms sodium
peroxide na2o to the other metals all
form superoxides for example see so2
the oxides and peroxides that form from
the alkali metals are typically white
solids as shown in the illustrations
they are basic and hydrates when placed
in water they will generate hydroxide
ions and thus basic solutions as shown
in this reaction for lithium
the alkali metal superoxides which only
formed with larger alkali metals are
typically yellow or orange in color
let's try some problem solving
what is the oxidation number of each
element in the compounds lithium oxide
sodium peroxide and rubidium superoxide
recall that the sum of the oxidation
numbers must be zero for a neutral
compound phone lithium oxide since each
lithium ion must have an oxidation
number of plus one the oxygen ion must
have a charge of minus two using similar
logic since each sodium ion has an
oxidation number of plus one each oxygen
in the peroxide ion must have an
oxidation number of minus one rubidium
here has an oxidation number of plus one
so each oxygen in the superoxide ion
must have an oxidation number of minus
half
as was mentioned earlier in this module
the alkali metals all react with water
these reactions release hydroxide ions
and hydrogen gas as shown in the
equation here the reactions become
increasingly more explosive down the
column
the alkali metals all react with
hydrogen
these reactions produce metal hydrides
which are ionic solids with high melting
points
the alkali metals react very vigorously
with the halogens one classic example
shown in the photo is the formation of
table salt or sodium chloride from
sodium metal and chlorine gas
the alkali metal halides are crystalline
solids as shown in the photographs they
have characteristically high melting
points and are soluble in water these
are very stable compounds as evidenced
by their large negative enthalpies of
formation
you
since the alkali metals have a high
tendency to lose their valence electrons
they oxidize readily when they oxidize
they cause some other substance to
become reduced and so we can say that
alkali metals are good reducing agents
remember the substance that is oxidized
in a redox reaction is called the
reducing agent
the alkali metals will dissolve in
liquid ammonia as the metals dissolve
the resulting solution turns blue as
shown in the photograph the blue color
is due to ammoniated electrons which
absorb visible light the solutions are
paramagnetic which means that they are
attracted to an externally applied
magnetic field when allowed to stand the
solutions slowly release hydrogen gas as
amides are formed as shown in the
reaction when concentrated these
solutions turn a bronze color and become
diamagnetic
let's go on and discuss some uses of the
alkali metals
lithium alloys are used for a variety of
purposes an alloy with lead is used to
make engine parts an aluminum lithium
alloy is used in airplane construction
and the magnesium lithium alloy is used
to make armored plates lithium metal is
used in some thermonuclear reactions and
to construct various types of batteries
liquid sodium is used as a coolant in
fast-breeder nuclear reactors
at one time a sodium lead alloy was used
to produce organ or lead compounds such
as tetra ethyl it which was used as an
anti-knock agent in automobile fuel the
use of leaded gasoline was phased out
due to the environmental pollution that
it caused
potassium has a variety of roles in
biological systems potassium chloride
sometimes called new rate of potage is
used as an agricultural fertilizer
potassium hydroxide is used to make soap
and to absorb carbon dioxide
cesium is used in the manufacture of
photoelectric cells in subsequent
modules we will discuss important
compounds of the alkali metals and their
biological roles
in some ways lithium is more similar to
magnesium which is in group two than the
other metals in group 1 this is
sometimes referred to as a diagonally
ship and it is due to the similarity in
the ionic radii and the charge or radius
ratios of these two elements compared to
the other metals in group 1 lithium has
a smaller radius and a higher charge or
radius ratio resulting in some anomalous
behavior
in what respects is lithium atypical
it is denser and harder than the other
members of its family and it's melting
and boiling points are higher than the
other alkali metals
lithium is the least reactive element in
the family yet it is the best reducing
agent
if you look at the table of standard
reduction potentials
lithium is at the bottom of the table
this means that for the group one metals
lithium has the strongest tendency to
oxidize
so lithium is at the top of the activity
series for single replacement reactions
additionally lithium chloride is the
only alkali metal chloride that forms a
hydrate lithium chloride dihydrate the
chloride salts of the other alkali
metals are anhydrous in many ways
lithium is an exceptional alkali metal
it's compound with the hydrogen
carbonate ion is not isolated in the
solid state
it does not form an eighth night
compound when reacting with a time
when lithium nitrate is heated the
decomposition reaction results in
lithium oxide
however other alkali metal nitrates form
nitrites when heated
this is shown in the equations
lithium nitrate decomposes to form
lithium oxide nitrogen dioxide and
oxygen gas
whereas the decomposition of sodium
nitrate yields sodium nitrite and oxygen
gas
the fluoride an oxide salts of lithium
are less soluble in water than the same
salts formed from the other alkali
metals for example only about 0.1 3 gram
of lithium fluoride will dissolve in 100
grams of water but it's possible to
dissolve about 4 grams of sodium
fluoride in 100 grams of water at the
same temperature
the diagonal relationship between
lithium and magnesium was mentioned
earlier in this module
lithium and magnesium have some notable
similarities in their chemical
properties
vote form nitrites as shown in the
reactions here
both react slowly with water
neither element forms compounds
containing the superoxide ion
there are two other similarities worth
mentioning about these two metals
first they're carbonates when heated
decompose to form a metal oxide and
carbon dioxide
both the metals form water soluble
chlorides that are found as hydrates
you
let's now talk about some important
compounds of sodium
sodium carbonate sodium chloride sodium
hydroxide and sodium hydrogen carbonate
sodium carbonate commonly known as
washing soda is a white crystalline
solid as shown in the photographs it is
typically found as a hydrate with ten
water molecules of crystallization
called sodium carbonate decahydrate when
heated nine of the water molecules of
crystallization are typically removed
forming the monohydrate salt
sodium carbonate is soluble in water
forming a colorless clear solution
about 373 Kelvin it forms an anhydrous
salt cold soda ash
most sodium carbonate is produced by the
Solway process which was developed in
the mid-1800s by Belgian chemist Ernest
Solvay
this process which has several steps
takes advantage of the low solubility of
sodium hydrogen carbonate in water
let's go through the steps of the sabe
process
in the first step ammonium carbonate is
synthesized from ammonia water and
carbon dioxide as shown the reaction
then the ammonium carbonate formed in
the first step is reacted with water and
carbon dioxide to form ammonium hydrogen
carbonate as shown in the reaction given
next the ammonium hydrogen carbonate is
combined with sodium chlorite and a
sodium hydrogen carbonate precipitate is
isolated
upon heating the sodium hydrogen
carbonate decomposes to form water
carbon dioxide and sodium carbonate
finally
ammonia is recovered by reacting the
ammonium chloride formed in step three
of the process
caption chlorite is the only by-product
of this entire process
here's a practice problem for you to
consider
why can't we use the Solvay process to
prepare potassium carbonate
answer potassium hydrogen carbonate is
too soluble it doesn't precipitate out
of the solution when ammonium hydrogen
carbonate reacts with potassium chloride
sodium carbonate has a variety of
household and industrial uses
it is used in water softening as well as
in laundry and cleaning
it is used in the manufacture of glass
and in the production of soap borax and
caustic soda otherwise known as sodium
hydroxide
certain carbonate is also necessary in
the paint paper and textile industries
additionally it is used in a variety of
analytical techniques in the chemical
laboratory
you
sodium chlorite is another important
compound of sodium
see water is an important source of
sodium chlorite
when sea water is evaporated it leaves
behind crude sodium chlorite
which contains several impurities
including calcium sulfate
chloride and magnesium chloride
sodium chloride is commonly used as
table salt and in the preparation of
other compounds that contain sodium
such as sodium hydroxide sodium
carbonate and sodium peroxide
like other ionic crystals sodium
chloride has a high melting point
of 1081 Kelvin
the photograph here shows a halite
Christian which is a naturally occurring
form of sodium chloride
as the green line in the solubility
diagram shows the solubility of sodium
chloride is nearly independent of
temperature
about 36 grams of sodium chloride can
dissolve in 100 grams of water between 0
and 100 degrees Celsius
another important compound that contains
sodium is sodium hydroxide
in its pure form it is a white solid
often sold in pellet form as shown in
the photograph
it is very caustic so don't touch it
sodium hydroxide melts at 591 Kelvin
it is delicious n't
it means that samples of sodium
hydroxide left in the open will absorb
water from the air and is on
you
sodium hydroxide is very soluble in
water the preparation of a solution of
sodium hydroxide is very exothermic
when preparing concentrated sodium
hydroxide solutions
it is necessary to place the container
in a nice spot
the solutions themselves are very basic
due to the presence of hydroxide ions
sodium hydroxide solutions will react
with carbon dioxide to form sodium
carbonate
sodium hydroxide is used for a variety
of purposes
it is used in the manufacture of soap
paper
and various textiles
it is used for refining petroleum
as a laboratory reagent and in the
preparation of fats and oils
sodium hydroxide can be prepared by the
electrolysis of brine solutions
that is sodium chloride solutions in the
Kastner killer cell
a schematic diagram of this electrolytic
cell is shown here
recall that the cathode is where
reduction occurs in an electrochemical
cell
in the Kastner killer cell mercury
functions as the cathode
in the reduction half-reaction sodium
ions combined with an electron to form a
sodium mercury amalgam
oxidation occurs at the anode in an
electrochemical cell
in the costner killer cell
a rod of graphite a form of carbon is
used as the anode in the oxidation
half-reaction chloride ions form
chlorine gas and release electrons
a sodium mercury amalgam that forms at
the cathode then reacts with water
releasing sodium hydroxide mercury metal
and hydrogen gas
you
making soda or sodium hydrogen carbonate
is another important compound that
contains sodium
when eat it it decomposes freezing
bubbles of carbon dioxide
it is used in baking to make the cakes
and pastries rights
one way to prepare sodium hydrogen
carbonate is through the reaction of
carbon dioxide with the solution of
sodium carbonate as shown here
sodium hydrogen carbonate is also formed
with the Solvay process
baking soda is used for a variety of
purposes
it is used in baking
as course
it can be used as mild skin antiseptic
as household cleaner
as an ingredient in mouthwash and
toothpaste and as treatment for
indigestion due to acidity
that is as an antacid
it is also used in certain types of fire
extinguishers
both sodium and potassium have important
biological drones they are present in
relatively large amounts in the human
body
in an average adults made
the body mass of 170 kg about 90 grams
of sodium and 170 grams of potassium are
present
compare this with the other essential
nutrients only about five grams of iron
and 0.06 gram of copper
this reflects the important roles both
sodium and potassium ion play in the
human body
you
sodium ions are found primarily in blood
plasma and the lymph fluid surrounding
the cells sodium ions play important
roles in nerve signal transmission
regulating the flow of water into the
cells
and the transport of sugars and amino
acids into the sense
by contrast potassium ions are the most
abundant cations inside the cells
potassium ions play important roles in
activating enzymes as well as the
oxidation of glucose to produce ATP
along with sodium ions potassium ions
are required for sending nerve signals
through the body
interesting Nouveau the concentration of
potassium ions is about 30 times higher
inside the cell than outside
the concentration of sodium ions outside
the cell is about 10 times higher than
inside the cell
there are sodium ion channels and
potassium ion channels in the cell
membranes
when these become activated sodium ions
rush into the cell and potassium ions
flow into the cell
the movement of sodium and potassium
ions against their concentration
gradients causes the polarity of the
membrane to charge momentarily
as this moves down the new Vaughn
the nerve signal travels through the
body
the sodium potassium pump a
transmembrane protein in cell membranes
uses active transport to move sodium and
potassium ions across cell membranes
against the concentration gradients
in doing so the sodium potassium pump
breaks down ATP molecules
this process alone accounts for about
one-third of the ATP used in animal
cells
the alkali earth metals which include
beryllium magnesium calcium strontium
barium and radium are found in group 2
of the periodic table they all have two
valence electrons the alkali earth
metals are not found as pure elements in
nature only in compounds these elements
with the exception of beryllium are
known as alkaline earth metals
these are so called because they're
oxides and hydroxides are alkaline in
nature and these metal oxides
are found in the Earth's crust
the most abundant elements in group 2
are calcium and magnesium
they are the fifth and sixth most
abundant elements in the Earth's crust
the other group two metals are
significantly rarer in nature oxide
compounds of group two elements are
found in the Earth's crust
the alkali earth metals have similar
properties because of their related
electron configurations since they all
have two valence electrons
they form cations with a charge of plus
two shown here are the electron
configurations of four alkali earth
metals notice how they all end as s2
showing those two valence electrons the
similarities in the electron
configurations have even more apparent
when written in noble gas notation the
ol end as NS 2 where n is the highest
occupied electron energy level because
of their two valence electrons all the
group 2 metals form cations with plus 2
charges by losing the two outermost
electrons they form cations that are
isoelectronic with the nearest noble gas
let's go on and review the periodic
trends as they relate to the alkali
earth metals in general
atomic radius decreases from left to
right in a period
in groups moving from left to right
outermost electrons enter into the same
electronic shell therefore size does not
increase more over outermost shell is
held more tightly by the increasing
nuclear charge
does we see that an alkaline earth metal
has a smaller atomic radius than the
group one metal in the same period
as shown in the graphic atomic radius
increases down the column
because the electrons enter into new
electronic shell and inner shells act as
screens for outer electrons
therefore outermost shell is held less
tightly by the nuclear challenge
this pattern rules for the group 2
metals as well
let's consider the ionic science trends
cations are smaller than their parent
atoms due to increased nuclear charge
as mentioned earlier the group 2 metals
typically form ions with a +2 charge as
shown in the graphic the group 2 cations
that form are significantly smaller than
the neutral metal atoms
recall that ionization energy is the
energy required to remove an electron
from a neutral isolated atom a typical
equation representing this change is
shown
in general ionization energy increases
from left to right across a period the
outermost electrons are held more
tightly as the nuclear charge increases
in accordance with this trend the
alkaline earth metals have high of first
ionization energies than the alkali
metals
the second ionization energy is the
energy required to remove the second
electron once the first electron has
been removed as indicated in the
equation here
generally second ionization energies are
higher than first ionization energies
one interesting fact you should know the
second ionization energies for the croup
two metals that is alkaline earth metals
are lower than the second ionization
energies for the group one metals that
is alkali metals
this is because losing one electron
through group one metal gives it a noble
gas like electron configuration
and losing another electron from these
cations becomes significantly less
favorable
the alkali earth metals have relatively
low ionization energies
however reflecting their high tendency
to lose electrons ionization energies
for the group two metals decrease down a
column so we can describe the alkali
earth metals as electro positive and
they become more electropositive down
the column
you
hydration and tau P is defined as the
amount of energy released when one mole
of anion is dissolved in a large
quantity of water as ionic size
increases hydration enthalpy decreases
therefore we observe a decrease in
hydration enthalpy from beryllium
through barium the group to metal ions
have larger hydration and thampi's than
the corresponding group one metal ions
many souls of the group 2 metals are
found as extensively hydrated salts for
example magnesium chloride and calcium
chloride both exist as EXA hydrates
neither potassium chloride no sodium
chloride is found as a hydrate however
let's discuss the physical properties of
the group 2 metals the alkali earth
metals are silvery white lustrous or
shiny solids
although beryllium and magnesium may
have a grayish cast to them they are
relatively soft metals though harder
than the alkali metals like all metals
they are good conductors of heat and
electricity the group 2 metals have
higher boiling points than the Group 1
metals due to their smaller atomic radii
similarly the group 2 metals have higher
melting points than the group 1 metals
in the same period although the trend is
not systematic
fling tests are a simple qualitative way
to test for the presence of metals by
holding a sample of the metal salt in
the flame and observing the change in
the kana the heat of the flame excites
the electrons to a higher energy level
and then the electrons emit light as
they return to the ground state calcium
salts produce a characteristic brick-red
flame strontium songs can be recognized
by the crimson flame that results
strontium salts are used to make
fireworks that emit red light míriam
gives an apple green color to the flame
why don't magnesium and beryllium
produce colored flames the electrons are
held tightly by the nuclei in these
elements and so the flames do not excite
them to higher energy levels magnesium
in fact will ignite in the flame and
react with oxygen giving off an intense
white light now we should discuss
various chemical properties of the
alkaline earth metals in general the
alkaline earth metals are less reactive
than the alkali metals the group two
metals form a variety of different types
of compounds
our focus is on the oxides
hydroxides
halides
cabinets
sulfates and nitrates
we'll discuss each of these in turn
magnesium and beryllium to not react
with water because both the metals form
an oxide layer on their surfaces
calcium strontium and barium all react
with water at normal temperature to form
hydroxides
action of calcium with water is shown
here
you
these hydroxides have low solubility in
water and are less basic than the group
1 metal hydroxides in general for the
group 2 metal hydroxides as the atomic
number of the metal increases the
solubility thermal stability and basic
character all increase beryllium
hydroxide
unlike the other group two metal
hydroxides is amphoteric
it can act as both an asset and as a
base
in the first reaction
beryllium hydroxide acts as a lewis acid
by accepting electron pairs from
hydroxide ions
in the second reaction
meridiem hydroxide acts as a base with
hydrochloric acid
why to the bloop two metal hydroxides
become more soluble down the group
recall that metal cations increase in
radius down the column
as inter nuclear distance increases
lattice energy decreases
less energy is required to separate the
ions
the hydration enthalpy
however
decreases less dramatically
the net result is that the souls are
more soluble in water
[Music]
William and magnesium do not react with
oxygen at normal temperature due to the
formation of an oxide film on their
surface
when burned in oxygen the group two
metals form metal oxides
for example burning calcium in the
presence of oxygen forms calcium oxide
magnesium and beryllium when ignited
will react vigorously in air releasing a
bright light both the oxide and the
nitride will form when reacting in air
as shown here in the reactions for
magnesium calcium strontium and barium
also react in air to form oxides and
nitrides
beryllium oxide is essentially covalent
in character
it is an amphoteric oxide meaning it can
act both as an asset and as a base
the other group two metal oxides are
essentially ionic substances
and the basic nature of websites
increases from magnesium to barium
with the exception of beryllium oxide
the group two metal oxides are basic and
hydrates this means that they reacts
with water to form metal hydroxides
all the group two metals can react with
halogens forming allied compounds these
reactions usually occur at high
temperatures for example calcium
fluoride forms when calcium metal reacts
with fluorine gas a sample of fluorite a
naturally occurring mineral of calcium
fluoride is shown in the photograph the
best synthetic route for preparing
beryllium fluoride is to heat ammonium
beryllium fluoride and tennety composes
as shown in the equation here
you
the rhenium chloride can be formed by
reacting beryllium oxide with chlorine
gas in the presence of carbon carbon
monoxide is a byproduct of this reaction
the highlight salts of the alkaline
earth metals are essentially ionic in
character
with the exception of the highlights of
beryllium
the beryllium halides are primarily
covalent
and thus
are soluble in organic solvents
in the solid state
Marine Ian chloride has a chain
structure
however
in the vapor seas
beryllium chloride forms a dimmer
these dimmers dissociate into monomers
at very high temperatures
the highlights of the group two elements
are often found as hydrates
but these sounds are complexed with
fewer water molecules down the column
does
magnesium fluoride is an octa hydrate
whereas Miriam chloride is found as a
dihydrate salt
these salts can be dehydrated upon
heating
leaving anhydrous songs
should be noted and beryllium and
magnesium salts will undergo hydrolysis
upon heating though
in general
the fluorides tend to be less soluble
than the chlorides
because of the higher lattice energies
associated with the fluoride salts
all of the group two metals with the
exception of pavilion react with
hydrogen to form metal hydrides the
reaction involving the formation of
calcium hydride is given here beryllium
hydride can be produced by reacting
beryllium chloride with lithium aluminum
hydride the group two metals react with
acids in a single replacement reaction
releasing hydrogen gas as a product
as a family the alkaline earth metals
have large negative reduction potentials
this feature reflects the strong
tendency of the metals to lose electrons
otherwise known as oxidation since
oxidation cannot occur without reduction
they can be considered good reducing
agents beryllium has a lower reduction
potential than the other group two
metals because it's cation is smaller
and has a larger atomization energy in
liquid ammonia
the group 2 metals dissolve to form
solutions with a deep blue-black color
ammoniated salt
of the general formula shown here
can be recovered from these solutions
you
the carbonates of the group 2 metals but
insoluble
they can be prepared by reacting soluble
carbonate salts such as Group one or
ammonium cabinets with soluble salts of
the group 2 metals one such reaction is
shown here a photograph of the mineral
calcite a naturally occurring form of
calcium carbonate is shown here the
group 2 metal carbonates decompose upon
heating to form the oxide and carbon
dioxide
a shill for cash in Kabul eat here
the White Cliffs of Dover consist
primarily of Cashin carbonate
the toll instability of calcium
carbonate increases as the metal cation
increases in size
pavilion carbonate is unstable and must
be kept in a carbon dioxide atmosphere
the sulfate salts of the group two
metals are white solids that are heat
stable
beryllium sulfate and magnesium sulfate
are water-soluble
but the solubility of this class of
compounds decreases down the column
this is because beryllium and magnesium
ions have higher hydration and talipes
than the other metals in the group
the group two metal nitrates can be
prepared by dissolving the carbonates in
dilute nitric acid
this class of compounds repeats the
pattern of the decreasing tendency to
form hydrates down the column
for example
magnesium nitrate is found as exha
hydrate
but Baden nitrate is anhydrous
when he did
all the group to metal nitrates
decompose to form oxides
as shown in the equation for the
decomposition of calcium nitrate
the alkali earth metals are used for a
variety of purposes
we'll wrap up this module with an
overview of the uses of these metals
pavilion is used in many industries
it is used to prepare several alloys
copper beryllium alloy is used to
manufacture high-strength Springs
metallic beryllium is used for the
windows of x-ray tubes
inhalation of beryllium dust
Veta
all its compounds can cause buried
losses
a serious form of mental poisoning
magnesium is also used to prepare a
noise
a magnesium aluminium alloy is used in
the construction of airplanes
ignition metal is used in flash powders
and flash bulbs for cameras
milk of magnesia
a suspension of magnesium hydroxide
is used as an antacid
magnesium carbonate is used as an
ingredient in toothpaste
calcium is used in the extraction of
metals from oxides
when they are too difficult to reduce
with carbon
Kancil along with barium
has been used to remove air from vacuum
tubes
the radioactive salts of radium are used
in the treatment of cancer
the certain respects
marillion does not behave like the other
group two metals
in particular
the compounds of beryllium have a
significant degree of covalent character
and are easily hydrolyzed
this is due to the exceptionally small
atomic and ionic radii observed for
barium
as well as its high ionization energy
and electronegativity compared to the
other group two metals
Miriam can achieve a maximum
coordination number of four
this is because there are a maximum of
four orbitals in the Williams outermost
energy level namely
the 2s and 2p orbitals
the other group two metals can utilize
the d-orbitals to have a coordination
number of six
the rhenium oxide and barium hydroxide
our amphoteric substances meaning the
big night is both acids and bases
for example
the first reaction shows pavilion
hydroxide acting as a base
neutralizing sulfuric acid
the second reaction shows barium
hydroxide acting as an acid to form the
complex ion better late
in several ways beryllium behaves more
like aluminium than the other group two
elements
it's what being familiar with the
details of this diagonal relationship
first the barium ion and aluminum ion
have similar charge to radius ratios as
shown here
neither beryllium no aluminium reacts
readily with acids
due to the oxide film then both the
metals exhibit on their surface
now hydroxides of both the metals
dissolve in solutions of excess
hydroxide to form complex ions
in the vapor phase
both beryllium chloride and aluminium
chloride form chloride bridged
structures
both the chlorides are soluble in
organic solvents
reflecting that essentially covalent
character
both the chlorides has strong lewis
acids
acting as electron pair acceptor in
chemical reactions
as shown in the reaction given here
both chlorides are used as catalysts in
the friedel-crafts reaction shown here
both beryllium ions and aluminium ions
form complex ions
next
we will consider some important
compounds of calcium
joshan bauxite
Yasim hydroxide
classroom sulfate calcium carbonate and
cement
gentle walk site which has the chemical
formula c a.o
is commonly known as quicklime
Yasim oxide is a white
amorphous solid with a melting point of
two thousand eight hundred and seventy
Kelvin
to prepare calcium oxide on an
industrial scale
limestone
Oh caco3 is heated in a row tricking at
1072 1270 kelvin
at these conditions
calcium carbonate decomposes to form
calcium oxide and carbon dioxide
the carbon dioxide is removed
continuously to drive the equilibrium to
the products
you
quicklime absorbs carbon dioxide and
moisture from the air
as shown in these reactions
when carbon dioxide is absorbed calcium
carbonate is the product
slacking of lime
shown in the second reaction
refers to the process in which when a
limited amount of water is added to a
lump of lime
it breaks up and results in the
formation of a suspension of sleep slime
along with the liberation of heat
this reaction also shows that calcium
oxide is a basic anhydride
since its reaction with water forms
calcium hydroxide which is alkaline
Jochem oxide is a basic oxide
and does can combine with acidic oxides
at high temperature
for example reactions with silicon
dioxide and phosphorus pentoxide are
given here
Joshu bauxite has a number of industrial
uses
it is necessary for the manufacture of
cement and is the cheapest form of
alkali
it is used to produce sodium carbonate
from sodium hydroxide
also known as caustic soda
it is used in the purification of sugar
and to the manufacture of ladies dyes
calcium hydroxide another important
compound of calcium
is commonly known as slaked lime
it is a white
amorphous powder that can be prepared by
adding water to calcium oxide
Ghanshyam hydroxide is only sparingly
soluble in water
aqueous solutions of calcium hydroxide
is commonly called lime water
milk of lime is the common name for
suspension of calcium hydroxide in water
9 water provides a simple test for the
presence of carbon dioxide
limewater turns milky when carbon
dioxide is passed into it
a precipitate of calcium carbonate forms
in this reaction
as shown here
if more carbon dioxide is passed into
the above solution
the precipitate dissolves and forms
calcium hydrogen carbonate
milk of lime
a suspension of calcium hydroxide in
water
reacts with chlorine gas to form calcium
hypochlorite
the main component of bleaching powder
hypochlorite ion is a good oxidizing
agent
you
calcium hydroxide is an important
industrial chemical
it is used in the preparation of motor
and to make whitewash
it is necessary for making glass as well
as for the tanning of leather
this was just discussed
it is used in the preparation of
bleaching powder
it is also used in the purification of
sugar
Jochem carbonate occurs naturally in
several phones
including limestone
Jacque and marble
in its pure state it is a white fluffy
powder that is nearly insoluble in water
upon heating
it decomposes to form calcium oxide and
carbon dioxide
calcium carbonate can be formed in two
ways
the first process involves passing
carbon dioxide through sleet line as
shown here
alternatively
sodium carbonate reacts with calcium
chloride to form calcium carbonate and
sodium chloride
this is shown here
- in carbonate is used for a variety of
purposes
it is well known as a building material
it is necessary in the manufacture of
quicklime
it is used industrially as a flux in
extracting metals from ores and in the
manufacture of high-quality beta
it is also used as an antacid
carbonate is an ingredient in toothpaste
and chewing gum
and is used as a filler in cosmetics
plaster-of-paris is a Hemi hydrate of
calcium sulfate
plaster-of-paris is formed when gypsum
or calcium sulfate dihydrate
is heated to 393 Kelvin
the decomposition reaction is shown here
it's gypsum is heated above 393 Kelvin
anhydrous calcium sulfate
or dead burnt plaster
we'll be the product
you
when water is added to plaster of Paris
it's arms a plastic
malleable mass that hardens in 5 to 15
minutes
plaster-of-paris is used in the building
industry
in medicine
it is also used to prepare costs to set
bone fractures
it has applications in dentistry too
the signs
plaster of Paris is used for ornamental
work
such as the ceiling medallion shown here
as well as statutes
saluté
or Portland cement as it is often called
is another important compound of culture
the raw materials for making cement are
limestone and clay
the composition of cement is not fixed
Portland cement typically contains 50 to
60% of calcium oxide and 20 to 25%
silicon dioxide as its main components
Cement also contains five to ten percent
aluminium oxide
due to 3% magnesium oxide
one to two percent int oxide
and one to two percent sulfur trioxide
you
in good quality cement
the ratio of silica
all silicon dioxide to alumina
or aluminum oxide
is between 2.5 and 4
the ratio of lime or calcium oxide to
the total oxides of silicon
aluminium and iron should be as close to
two as possible
cement clinker is formed when clay and
line are strongly heated
we fuse together to form cement clinker
shown in the photograph
to form cement due to 3% gypsum by mass
is added to the cement clinker
this mixture is then ground to make
cement
ingredients that make up the bulk of
Portland cement include die calcium
silicate
making up 26%
try calcium silicate
contributing 51%
and tricalcium aluminate
contributing 11%
you
Cement sets when it is mixed with water
to form a hard masse
the molecules of the components get
rearranged and hydrated
the presence of gypsum slows down the
setting process so that it gets very
hard
Cement is used to make concrete and
reinforced concrete
it is used in plastering
as when
it is best known for its use in the
construction of bridges
dams and buildings of all sorts
both magnesium and calcium play importer
tools and biological systems
an adult human body contains 25 grams of
magnesium and 1,200 grams of calcium
compare this with only five grams of
iron and 0.06 gram of copper
let's go into these important functions
in more detail
phosphoryl transfer enzymes
which use ATP in phosphate transfer
use a magnesium ion as a cofactor for
enzyme function
an illustration of one such enzyme is
shown here
with the magnesium ion shown in green
beautiful is the main pigment in plants
that absorbs light for photosynthesis
the porphyrin ring in chlorophyll
contains magnesium
bones and teeth contain about 99% of the
consumed in the human body
born which is alive
the complex structure
is continuously being solubilized and
redeposited in the body
approximately 100 milligrams of calcium
are dissolved in 1 liter of plasma
this concentration is regulated by the
action of two hormones
calcitonin and parathyroid hormone
calcium ions play an essential role in
muscle contraction
the diagram of the sliding filament
theory of muscle contraction is shown
here
consume ions also play an important role
in blood coagulation
Jochem ions are essential for the
transmission of signals between nerve
cells
calcium ions are important for cell
signaling and for various physiological
processes
can't shoot channels regulate the
transportation of calcium ions across
cell membranes
[Music]
[Applause]
[Music]
you

where is the s-block in the periodic

Toggle Transcript

How to pronounce potassium hydrogen carbonate in English?

Related

Subscribe to our Newslatter