Question

When 1.020 g of ethanol (C2H6O, 46.07 g/mol) was burned in a bomb calorimeter containing 2400. g of water, the temperature of the water rose from 22.46 to 25.52ºC. The specific heat of water is 4.18 J/g-°C. What is the enthalpy of combustion of 1 mol of ethanol? What is the heat capacity of the calorimeter?

Answer #1

Given

Mass of ethanol = 1.020 g

Molar mass = 46 g/mol

No. of moles = Mass of ethanol / Molar mass = 1.020 g / 46 g/mol = 0.0222 moles

Mass of water = 2400 g

Molar mass of water = 18 g/mol

No. of moles of water = 2400 g / 18 g/mol = 133.33 moles

Specific heat of water Cp = 4.18 J/g.C

Intial Temperature = 22.46 C

FInal temperature T2 = 25.52 C

heat released from ethanol = heat absorbed by water = (m*Cp*(T2-T1)) of water

heat released from ethanol = 2400 g * 4.18 J/g.C ( 25.52 - 22.46) C = 30697.92 J

0.0222 moles of ethanol released 30697.92 J

so Enthalpy of combustion of 1 mole of ethanol = 30697.92 J / 0.0222 moles = 1382.79 KJ//mol Answer

A 12.8 g sample of ethanol (C2H5OH) is
burned in a bomb calorimeter with a heat capacity of 5.65
kJ/°C. The temperature of the calorimeter and the contents
increases from 25°C to 35°C. What is the heat of
combustion per mole of ethanol? The molar mass of ethanol is 46.07
g/mol.
C2H5OH (l) + 3 O2 (g) -----> 2 CO2 (g) + 3
H2O (g) ΔE = ?

A 1.000 g sample of octane (C8H18) is burned in a bomb
calorimeter containing 1200 grams of water at an initial
temperature of 25.00ºC. After the reaction, the final temperature
of the water is 33.20ºC. The heat capacity of the calorimeter (also
known as the “calorimeter constant”) is 837 J/ºC. The specific heat
of water is 4.184 J/g ºC. Calculate the heat of combustion of
octane in kJ/mol.

A 2.50 mol sample of benzene (C6H6, 78.11 g/mol) was burned in a
bomb calorimeter with a heat capacity of 800 J/°C. The calorimeter
contained 100g of water (4.18J/g°C) and the temperature increased
by 4°C. What is the molar enthalpy of combustion for this
compound?

. A 0.500 g sample of naphthalene (C10H8) is burned in a bomb
calorimeter containing 650 grams of water at an initial temperature
of 20.00 oC. After the reaction, the final temperature of the water
is 26.4ºC. The heat capacity of the calorimeter is 420 J/oC. Using
these data, calculate the heat of combustion of naphthalene in
kJ/mol.

When 86.6 g of a compound was burned in a bomb calorimeter that
contained 0.184 kg of water the temperature rise of the water in
the calorimeter was 57.0C. If the heat of combustion of the
compound is 1,396 kJ/mol, what is the molar mass of the compound?
Specific heat of water is 4.184 J/gC. Answer to 0 decimal places
and enter the units.

A 0.553-g sample of diphenyl
phthalate
(C20H14O4) is
burned in a bomb calorimeter and the temperature increases from
24.40 °C to 27.57 °C. The
calorimeter contains 1.08×103 g of
water and the bomb has a heat capacity of 877
J/°C. The heat capacity of water is 4.184 J
g-1°C-1. Based on this experiment, calculate
ΔE for the combustion reaction per mole of diphenyl
phthalate burned.
______ kJ/mol

A 0.373-g sample of naphthalene (C10H8) is burned in a bomb
calorimeter and the temperature increases from 24.90 °C to 27.80
°C. The calorimeter contains 1.05E3 g of water and the bomb has a
heat capacity of 836 J/°C. Based on this experiment, calculate ΔE
for the combustion reaction per mole of naphthalene burned
(kJ/mol).

A 0.287-g sample of bianthracene (C28H18) is burned in a bomb
calorimeter and the temperature increases from 25.30 °C to 27.50
°C. The calorimeter contains 1.03E3 g of water and the bomb has a
heat capacity of 856 J/°C. Based on this experiment, calculate ΔE
for the combustion reaction per mole of bianthracene burned
(kJ/mol).

Part A
When 2.275 g of anthracene, C14H10, is
combusted in a bomb calorimeter that has a water jacket containing
500.0 g of water, the temperature of the water increases by
43.15°C. Assuming that the specific heat of water is 4.18 J/(g •
°C), and that the heat absorption by the calorimeter is negligible,
estimate the enthalpy of combustion per mole of anthracene.
Part B
The specific heat capacity of methane gas is 2.20 J/g• K. How
many joules of...

6g of ethanol C2H5OH is burned completely at 298.15K in a bomb
calorimeter, and the heat produced is 180.39kJ
a) calculate the enthalpy of combustion for ethanol under these
conditions
(in kJ/mol)
b) using the result from part a), calculate the heat of
formation for ethanol (in kJ/mol)

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