Question

Part A A calorimeter contains 21.0 mL of water at 11.0 ∘C . When 1.60 g of X (a substance with a molar mass of 72.0 g/mol ) is added, it dissolves via the reaction X(s)+H2O(l)→X(aq) and the temperature of the solution increases to 26.0 ∘C . Calculate the enthalpy change, ΔH, for this reaction per mole of X. Assume that the specific heat of the resulting solution is equal to that of water [4.18 J/(g⋅∘C)], that density of water is 1.00 g/mL, and that no heat is lost to the calorimeter itself, nor to the surroundings. Express the change in enthalpy in kilojoules per mole to three significant figures. part b Consider the reaction C12H22O11(s)+12O2(g)→12CO2(g)+11H2O(l) in which 10.0 g of sucrose, C12H22O11, was burned in a bomb calorimeter with a heat capacity of 7.50 kJ/∘C. The temperature increase inside the calorimeter was found to be 22.0 ∘C. Calculate the change in internal energy, ΔE, for this reaction per mole of sucrose. Express the change in internal energy in kilojoules per mole to three significant figures.

Answer #1

**PART A**

**mass of the mixture = v*d+mass of X**

**= 21.0*1+1.6 = 22.6 g**

**s = specific heat of mixture = 4.184 j/g.c**

**DT = 26-11 = 15c**

**heat released(q) = m*s*DT**

** = 22.6*4.184*15**

** = 1.418 kj**

**no of mol of X = w/mwt = 1.6/72 = 0.022 mol**

**DHrxn = -q/n**

** =
-1.418/0.022**

** = -64.4
kj/mol**

**part B**

**heat released during combustion reaction(q) =
C*DT**

** = 7.5*22**

** = 165 kj**

**No of mol of sucrose burned = w/mwt = 10/342.3 = 0.0292
mol**

**DUrxn = -q/n = -165/0.0292 = -5650.7 kj/mol**

**
answer: -5.65*10^3 kj/mol**

Part A
A calorimeter contains 35.0 mL of water at 11.0 ∘C . When 1.30 g
of X (a substance with a molar mass of 46.0 g/mol ) is added, it
dissolves via the reaction
X(s)+H2O(l)→X(aq)
and the temperature of the solution increases to 29.0 ∘C .
Calculate the enthalpy change, ΔH, for this reaction
per mole of X.
Assume that the specific heat of the resulting solution is equal
to that of water [4.18 J/(g⋅∘C)], that density of water...

Consider the reaction
C12H22O11(s)+12O2(g)→12CO2(g)+11H2O(l)
in which 10.0 g of sucrose, C12H22O11, was burned in a bomb
calorimeter with a heat capacity of 7.50 kJ/∘C. The temperature
increase inside the calorimeter was found to be 22.0 ∘C. Calculate
the change in internal energy, ΔE, for this reaction per
mole of sucrose.
Express the change in internal energy in kilojoules per mole to
three significant figures.
Hints
ΔE =
kJ/mol

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When 1.20 g of X (a substance with a molar mass of 73.0 g/mol ) is
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When 1.80 g of X (a substance with a molar mass of 72.0 g/mol ) is
added, it dissolves via the reaction
X(s)+H2O(l)→X(aq)
and the temperature of the solution increases to 27.0 ∘C .
Calculate the enthalpy change, ΔH, for this reaction
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Assume that the specific heat of the resulting solution is equal
to that of water [4.18 J/(g⋅∘C)], that density of water...

A calorimeter contains 30.0 mL of water at 11.5 ∘C . When 2.10 g
of X (a substance with a molar mass of 42.0 g/mol ) is added, it
dissolves via the reaction
X(s)+H2O(l)→X(aq)
and the temperature of the solution increases to 30.0 ∘C .
Calculate the enthalpy change, ΔH, for this reaction
per mole of X.
Assume that the specific heat of the resulting solution is equal
to that of water [4.18 J/(g⋅∘C)], that density of water is 1.00...

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of X (a substance with a molar mass of 46.0 g/mol ) is added, it
dissolves via the reaction
X(s)+H2O(l)→X(aq)
and the temperature of the solution increases to 28.0 ∘C .
Calculate the enthalpy change, ΔH, for this reaction
per mole of X.
Assume that the specific heat of the resulting solution is equal
to that of water [4.18 J/(g⋅∘C)], that density of water is 1.00...

The combustion of 1.961 g of sucrose, C12H22O11(s), in a bomb
calorimeter with a heat capacity of 4.00 kJ/°C results in an
increase in the temperature of the calorimeter and its contents
from 22.92 °C to 31.00 °C. Calculate the enthalpy of combustion,
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Δ?c= kJ/mol
What is the internal energy change, Δ?, for the combustion of
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Δ?= kJ

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Find ΔErxn for the reaction in kJ/mol hexane. The heat
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A calorimeter is an insulated device in which a chemical
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Express the energy in kilojoules per mole to three
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