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How to pronounce bomb calorimeter in English?

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in this video we're going to talk about
how to solve this bomb calorimeter
problem
but before we go into it
i want to highlight the difference
between the coffee cup calorimeter
and the bomb calorimeter
so in the coffee cup calorimeter
we're basically going to use a cup
ideally made up of styrofoam because
styrofoam is a good thermal insulator
so we're going to have some water in the
cup
and we need a thermometer to measure the
temperature of
the water sample
and then we're going to dissolve
something
into the solution
so maybe like calcium chloride
and calcium chloride when dissolved in
water releases energy
and so the water molecules absorb that
energy
and
the temperature of the water
is measured
and based on the change in temperature
you can calculate how much energy was
absorbed by the solution and so you can
calculate the enthalpy change of calcium
chloride so this is
the coffee cup calorimeter
and it needs to be sealed
now what you need to understand is that
the coffee cup calorimeter
measures the energy change
at constant pressure
because you have gas particles in the
air
the pressure is going to be 1 atm at sea
level
now in the bomb calorimeter
the energy
is calculated at constant volume
so why is this important to know
this is important to know because
enthalpy
is the energy
that is transferred
only when measured at constant pressure
so if you wish to calculate the enthalpy
of something you want to use the coffee
cup calorimeter
because the enthalpy change is equal to
the heat absorbed or released when
measured at constant pressure
now in a bomb calorimeter
the energy is measured at constant
volume so you don't want to use that to
calculate enthalpy
that's why this question says calculate
the energy of combustion not the
enthalpy of combustion
now in the bottom calorimeter you're
going to have water as well
but you're going to have a separate
chamber known as a combustion chamber
let's put it on this side
and basically it's just
a container that doesn't expand it's a
rigid container
and so the volume of that container is
held constant
now you're going to have some ignition
wires
that
extend
from the combustion chamber
to outside of the bomb calorimeter
and the purpose of the ignition wires is
to
basically
ignite the sample
once this sample is ignited
it's going to release thermal energy
into the surrounding environment
and so water
is going to absorb that thermal energy
and so you need a thermometer to measure
the temperature change of the water
and also you might have like a
some type of steering device to keep
the fluid flowing to transfer energy
throughout
the entire
solution
so that's the picture of the bomb
calorimeter
it's similar to the coffee cup
calorimeter but you just have a
combustion chamber
and just keep in mind that the energy
changes
are measured at constant
volume
so that's important to know
so now let's focus on the problem at
hand
3.36 grams of ethanol
is burned in a bomb calorimeter with a
heat capacity of 2.3 kilojoules per
celsius
the temperature of the calorimeter
increases from 12.1 to 55.5 celsius
calculate the energy of combustion per
mole
so how can we do this
the energy released by the reaction
is equal to the energy absorbed by
the water sample
now how can we calculate this q
because we're not given a specific heat
capacity of water
we know what it is that was 4.184 joules
per gram per celsius but we don't know
the mass
of water
in the sample
so we need to calculate the q that's
absorbed by
the calorimeter as a whole because we're
given the heat capacity of the
calorimeter
now you need to be careful
if you wish to calculate q and you're
given the specific heat capacity
you need to use this equation m c delta
t
but if you're given the heat capacity
it's simply c delta t
and the units basically tell you that
notice that for the heat capacity the
units
are kilojoules per celsius
so if we multiply kilojoules per celsius
by the temperature change in celsius
it's going to give us
the energy in kilojoules which we're
going to divide it by moles later
but when you're dealing with specific
heat capacity
c is going to have units joules per gram
per celsius
and so you need to multiply
c by m so that the unit grams will
cancel
and once you multiply by delta t
celsius will cancel giving you joules
or this could be kilojoules too as well
so now let's go ahead and calculate
the heat energy that's absorbed by the
calorimeter
so that's going to be the heat capacity
multiplied by the change in temperature
the heat capacity is 2.3 kilojoules per
celsius
and the change in temperature
it's final minus initial
so that's going to be
55.5 minus 12.1
so that's a change in temperature of
43.4 degrees celsius
so we multiply 2.3 by 43.4
that gives us
99.82
kilojoules
and because the temperature of the
calorimeter increased
we could say that the process is
endothermic for the calorimeter heat was
absorbed by the calorimeter which means
that heat had to be released by the
reaction
so q of the reaction is equal to
negative q of the calorimeter the
calorimeter is the surroundings the
reaction is the system
so if the surroundings
is undergoing an endothermic process
the system has to be undergoing an
exothermic process
so q of the reaction is negative
99.82 kilojoules
now we need the energy
of combustion per mole
so we have the grams of ethanol we need
to convert that to moles
but let's calculate the molar mass first
so in ethanol we have two carbon atoms
a total of six hydrogen atoms
five plus one is six
and then
just a single
oxygen atom
so the atomic mass of carbon is 12.01
and the atomic mass of hydrogen is 1.008
and oxygen is 16.
so type that in exactly the way you see
it in your calculator
so you should get a molar mass of 46.068
grams per mole
so let's start with
3.36 grams of ethanol
and let's convert its moles
so to calculate the number of moles you
just simply have to take the mass
and divide it by the molar mass so it's
3.36 divided by 46.068
and so this is going to be
0.0729 moles
so now to calculate the energy of
combustion
per mole
we need to take the energy in kilojoules
and divide it by the number of moles
so it's going to be negative
99.82 kilojoules
by
0.0729 moles
so it's going to be about if you round
it to three sig figs it's negative 1370
kilojoules per mole
so that's the energy of combustion
per mole
for the substance ethanol
you

in this video we're going to talk about

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bomb calorimeter::noun | Spocien Dictionary

bomb calorimeter

noun

/bɑm_,kælə'rɪmɪtər/

strong sealed vessel for measuring heat of combustion

Type	Words
Synonyms	bomb
Type of	calorimeter

Examples of bomb calorimeter

bomb calorimeter

Another example of a closed system is a bomb calorimeter, a type of constant-volume calorimeter used in measuring the heat of combustion of a particular reaction.

From the en.wikipedia.org

The internal energy change of a process is equal to the heat change if it is measured under conditions of constant volume, as in a closed rigid container such as a bomb calorimeter.

From the en.wikipedia.org

How to pronounce bomb calorimeter in English?

bomb calorimeter::noun | Spocien Dictionary

abandonment

Related words

Examples of bomb calorimeter

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