Question 1

An unknown metal alloy,mass = 26.3 g,has a temperature increase of 8.31 °C after a heat transfer of 94.0 J.Calculate the specific heat capacity of the alloy.

Accepted Answer

A) 0.813 J g-1 °C-1 
B) 0.517 J g-1 °C-1 
C) 0.349 J g-1 °C-1 
D) 0.288 J g-1 °C-1 
E) 0.430 J g-1 °C-1 
A) 0.813 J g-1 °C-1 
B) 0.517 J g-1 °C-1 
C) 0.349 J g-1 °C-1 
D) 0.288 J g-1 °C-1 
E) 0.430 J g-1 °C-1

Question 2

Which of the following processes is exothermic?

Accepted Answer

A) the formation of dew in the morning 
B) the melting of ice 
C) the chemical reaction in a "cold pack" often used to treat injuries 
D) the vaporization of water 
E) None of the above is exothermic. 
A) the formation of dew in the morning 
B) the melting of ice 
C) the chemical reaction in a "cold pack" often used to treat injuries 
D) the vaporization of water 
E) None of the above is exothermic.

Question 3

At constant pressure,the combustion of 20.0 g of C2H6(g)releases 1036 kJ of heat.What is ?H for the reaction given below? 
2C2H6(g)+ 7O2(g)? 4CO2(g)+ 6H2O(l)

Accepted Answer

A) -173 kJ $\mathrm { mol } ^ { - 1 }$ 
B) -779 kJ $\mathrm { mol } ^ { - 1 }$ 
C) -1560 kJ $\mathrm { mol } ^ { - 1 }$ 
D) -3120 kJ $\mathrm { mol } ^ { - 1 }$ 
A) -173 kJ $\mathrm { mol } ^ { - 1 }$ 
B) -779 kJ $\mathrm { mol } ^ { - 1 }$ 
C) -1560 kJ $\mathrm { mol } ^ { - 1 }$ 
D) -3120 kJ $\mathrm { mol } ^ { - 1 }$

Question 4

An 8.21 g sample of glycerol (C3H8O3,molar mass = 92.0938 g $\mathrm { mol } ^ { - 1 }$ )was combusted in a bomb calorimeter with a heat capacity of 10.61 kJ ${ } ^ { \circ } \mathrm { C } ^ { - 1 }$ .If the temperature increased from 22.1 °C to 36.0 °C,determine $D _ { \mathrm { r } }$ U for the combustion of glycerol.

Accepted Answer

A) -4.38 × 103 kJ mol-1 
B) 3.65 × 103 kJ mol-1 
C) 2.18 × 103 kJ mol-1 
D) -2.18 × 103 kJ mol-1 
E) -1.65 × 103 kJ mol-1 
A) -4.38 × 103 kJ mol-1 
B) 3.65 × 103 kJ mol-1 
C) 2.18 × 103 kJ mol-1 
D) -2.18 × 103 kJ mol-1 
E) -1.65 × 103 kJ mol-1

Question 5

The standard state of sulfur is ________.

Accepted Answer

The answer of The standard state of sulfur is ________....

Question 6

Use the DfH°° and DrH°information provided to calculate DfH° for IF: $$\begin{array} { l c c } 
& \mathrm { D } _ { \mathrm { f } } H ^ { \circ } \left( \mathrm { kJ } \mathrm { mol } ^ { - 1 } \right) & \mathrm { IF } 7 ( g ) + \mathrm { I } _ { 2 } ( g ) \rightarrow \mathrm { IF } _ { 5 } ( g ) + 2 \operatorname { IF } ( g ) \quad \mathrm { D } _ { \mathrm { r } } H ^ { \circ } = - 89 \mathrm {~kJ} \
\operatorname { IF } _ { 7 } ( g ) & - 941 \
\operatorname { IF } _ { 5 } ( g ) & - 840
\end{array}$$

Accepted Answer

A) 101 kJ mol-1 
B) -146 kJ mol-1 
C) -190.kJ mol-1 
D) -95 kJ mol-1 
E) 24 kJ mol-1 
A) 101 kJ mol-1 
B) -146 kJ mol-1 
C) -190.kJ mol-1 
D) -95 kJ mol-1 
E) 24 kJ mol-1

Question 7

Using the following equation for the combustion of octane,calculate the amount of grams of carbon dioxide formed from 100.0 g of octane.The molar mass of octane is 114.33 g mol-1.The molar mass of carbon dioxide is 44.0095 g mol-1. 2C8H18 + 25O2 → 16CO2 + 18H2O 
DrH° = -11018 kJ

Accepted Answer

A) 800.1 g 
B) 307.9 g 
C) 260.1 g 
D) 792.3 g 
A) 800.1 g 
B) 307.9 g 
C) 260.1 g 
D) 792.3 g

Question 8

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g-1 °C-1)at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.

Accepted Answer

A) -53 J 
B) 53 J 
C) 82 J 
D) -82 J 
E) 93 J 
A) -53 J 
B) 53 J 
C) 82 J 
D) -82 J 
E) 93 J

Question 9

Determine the final temperature of a gold nugget (mass = 376 g)that starts at 398 K and loses 4.85 kJ of heat to a snowbank when it is lost.The specific heat capacity of gold is 0.128 J g-1 °C-1.

Accepted Answer

A) 133 K 
B) 398 K 
C) 187 K 
D) 297 K 
E) 377 K 
A) 133 K 
B) 398 K 
C) 187 K 
D) 297 K 
E) 377 K

Question 10

Use the standard reaction enthalpies given below to determine DrH° for the following reaction: P4(g)+ 10Cl2(g)? 4PCl5(s) 
DrH°0= ?
Given:
PCl5(s)? PCl3(g)+ Cl2(g) $D _ { \mathrm { r } }$ H°= +157 kJ
P4(g)+ 6Cl2(g)? 4PCl3(g) $D _ { \mathrm { r } }$ H° = -1207 kJ

Accepted Answer

A) -1835 kJ mol-1 
B) -1364 kJ mol-1 
C) -1050 kJ mol-1 
D) -1786 kJ mol-1 
E) -2100 kJ mol-1 
A) -1835 kJ mol-1 
B) -1364 kJ mol-1 
C) -1050 kJ mol-1 
D) -1786 kJ mol-1 
E) -2100 kJ mol-1

Question 11

How much energy is evolved during the formation of 98.7 g of Fe according to the reaction below? Fe2O3(s)+ 2Al(s)→ Al2O3(s)+ 2Fe(s) 
DrH° = -852 kJ

Accepted Answer

A) 753 kJ 
B) 1.51 × 103 kJ 
C) 4.20 × 103 kJ 
D) 482 kJ 
E) 241 kJ 
A) 753 kJ 
B) 1.51 × 103 kJ 
C) 4.20 × 103 kJ 
D) 482 kJ 
E) 241 kJ

Question 12

Using the following thermochemical equation,determine the amount of heat produced per kg of CO2 formed during the combustion of benzene (C6H6). 2C6H6(l)+ 15O2(g)→ 12CO2(g)+ 6H2O(g) 
DrH° = -6278 kJ

Accepted Answer

A) 1.43 × 105 kJ (kg CO2)-1 
B) 2.30 × 104 kJ (kg CO2)-1 
C) 4.34 × 104 kJ (kg CO2)-1 
D) 1.19 × 104 kJ (kg CO2)-1 
E) 8.40 × 105 kJ (kg CO2)-1 
A) 1.43 × 105 kJ (kg CO2)-1 
B) 2.30 × 104 kJ (kg CO2)-1 
C) 4.34 × 104 kJ (kg CO2)-1 
D) 1.19 × 104 kJ (kg CO2)-1 
E) 8.40 × 105 kJ (kg CO2)-1

Question 13

Choose the reaction that illustrates DfH° for Ca(NO3)2.

Accepted Answer

A) Ca(s)+ N2(g)+ 3O2(g)→ Ca(NO3)2(s) 
B) Ca2+(aq)+ 2NO3-(aq)→ Ca(NO3)2(aq) 
C) Ca(s)+ 2N(g)+ 6O(g)→ Ca(NO3)2(s) 
D) Ca(NO3)2(aq)→ Ca2+(aq)+ 2NO3-(aq) 
E) Ca(NO3)2(s)→ Ca(s)+ N2(g)+ 3O2(g) 
A) Ca(s)+ N2(g)+ 3O2(g)→ Ca(NO3)2(s) 
B) Ca2+(aq)+ 2NO3-(aq)→ Ca(NO3)2(aq) 
C) Ca(s)+ 2N(g)+ 6O(g)→ Ca(NO3)2(s) 
D) Ca(NO3)2(aq)→ Ca2+(aq)+ 2NO3-(aq) 
E) Ca(NO3)2(s)→ Ca(s)+ N2(g)+ 3O2(g)

Question 14

A 12.8 g sample of ethanol (C2H5OH)is burned in a bomb calorimeter with a heat capacity of 5.65 kJ ${ } ^ { \circ } \mathrm { C } ^ { - 1 }$ .Using the information below,determine the final temperature of the calorimeter if the initial temperature is 25.0°C.The molar mass of ethanol is 46.07 g $\mathrm { mol } ^ { - 1 }$ . C2H5OH(l)+ 3O2(g)? 2CO2(g)+ 3H2O(g) $D _ { \mathrm { r } }$ U = -1235 kJ $\mathrm { mol } ^ { - 1 }$

Accepted Answer

A) 53.4 °C 
B) 28.1 °C 
C) 111 °C 
D) 85.7 °C 
E) 74.2 °C 
A) 53.4 °C 
B) 28.1 °C 
C) 111 °C 
D) 85.7 °C 
E) 74.2 °C

Question 15

Use the standard reaction enthalpies given below to determine DrH° for the following reaction: 4SO3(g)→ 4S(s)+ 6O2(g) DrH°= ?
Given:
SO2(g)→ S(s)+ O2(g) DrH°= +296.8 kJ
2SO2(g)+ O2(g)→ 2SO3(g) DrH°= -197.8 kJ

Accepted Answer

A) -494.6 kJ mol-1 
B) -692.4 kJ mol-1 
C) -791.4 kJ mol-1 
D) 1583 kJ mol-1 
E) -293.0 kJ mol-1 
A) -494.6 kJ mol-1 
B) -692.4 kJ mol-1 
C) -791.4 kJ mol-1 
D) 1583 kJ mol-1 
E) -293.0 kJ mol-1

Question 16

Using the following equation for the combustion of octane,calculate the amount of moles of carbon dioxide formed from 100.0 g of octane.The molar mass of octane is 114.33 g $\mathrm { mol } ^ { - 1 }$ .The molar mass of carbon dioxide is 44.0095 g $\mathrm { mol } ^ { - 1 }$ . 2C8H18 + 25O2 ? 16CO2 + 18H2O 
DrH° = -11018 kJ

Accepted Answer

A) 18.18 moles 
B) 6.997 moles 
C) 14.00 moles 
D) 8.000 moles 
E) 10.93 moles 
A) 18.18 moles 
B) 6.997 moles 
C) 14.00 moles 
D) 8.000 moles 
E) 10.93 moles

Question 17

How much heat is absorbed/released when 40.00 g of NH3(g)reacts in the presence of excess $\mathrm { O } _ { 2 }$ (g)to produce NO(g)and H2O(l)according to the following chemical equation? 
4NH3(g)+ 5O2(g)? 4NO(g)+ 6H2O(l) $\Delta _ { \mathrm { r } }$ H° = 1168 kJ

Accepted Answer

A) 685.8 kJ of heat are absorbed. 
B) 685.8 kJ of heat are released. 
C) 2743 kJ of heat are absorbed. 
D) 2743 kJ of heat are released. 
A) 685.8 kJ of heat are absorbed. 
B) 685.8 kJ of heat are released. 
C) 2743 kJ of heat are absorbed. 
D) 2743 kJ of heat are released.

Question 18

What volume of benzene (C6H6,d = 0.88 g mL-1,molar mass = 78.11 g mol-1)is required to produce 1.5 × 103 kJ of heat according to the following reaction? 2C6H6(l)+ 15O2(g)→ 12CO2(g)+ 6H2O(g) 
DrH° = -6278 kJ

Accepted Answer

A) 75 mL 
B) 37 mL 
C) 21 mL 
D) 19 mL 
E) 42 mL 
A) 75 mL 
B) 37 mL 
C) 21 mL 
D) 19 mL 
E) 42 mL

Question 19

Identify an energy source that is non-renewable.

Accepted Answer

A) solar 
B) hydroelectric 
C) coal 
D) wind 
E) sun 
A) solar 
B) hydroelectric 
C) coal 
D) wind 
E) sun

Question 20

A bomb calorimeter with a heat capacity of 13.9 kJ °C-1 has an initial temperature of 21.9 °C.If 5.00 g of propanal (C3H6O,molar mass = 58.0791 g mol-1,DrU = -1822.7 kJ mol-1 for combustion)is combusted,calculate the final temperature of the calorimeter.

Accepted Answer

A) 26.1 °C 
B) 16.7 °C 
C) 33.2 °C 
D) 43.1 °C 
E) 34.0 °C 
A) 26.1 °C 
B) 16.7 °C 
C) 33.2 °C 
D) 43.1 °C 
E) 34.0 °C

Exam 6: Thermochemistry

An unknown metal alloy,mass = 26.3 g,has a temperature increase of 8.31 °C after a heat transfer of 94.0 J.Calculate the specific heat capacity of the alloy.

Which of the following processes is exothermic?

At constant pressure,the combustion of 20.0 g of C2H6(g)releases 1036 kJ of heat.What is ?H for the reaction given below? 2C2H6(g)+ 7O2(g)? 4CO2(g)+ 6H2O(l)

The standard state of sulfur is ________.

Use the DfH°° and DrH°information provided to calculate DfH° for IF: 7(g)+(g)\rightarrow(g)+2 IF (g)=-89 (g) -941 (g) -840

Using the following equation for the combustion of octane,calculate the amount of grams of carbon dioxide formed from 100.0 g of octane.The molar mass of octane is 114.33 g mol-1.The molar mass of carbon dioxide is 44.0095 g mol-1. 2C8H18 + 25O2 → 16CO2 + 18H2O DrH° = -11018 kJ

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g-1 °C-1)at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.

Determine the final temperature of a gold nugget (mass = 376 g)that starts at 398 K and loses 4.85 kJ of heat to a snowbank when it is lost.The specific heat capacity of gold is 0.128 J g-1 °C-1.

Use the standard reaction enthalpies given below to determine DrH° for the following reaction: P4(g)+ 10Cl2(g)? 4PCl5(s) DrH°0= ? Given: PCl5(s)? PCl3(g)+ Cl2(g) DrD _ { \mathrm { r } }Dr​ H°= +157 kJ P4(g)+ 6Cl2(g)? 4PCl3(g) DrD _ { \mathrm { r } }Dr​ H° = -1207 kJ

How much energy is evolved during the formation of 98.7 g of Fe according to the reaction below? Fe2O3(s)+ 2Al(s)→ Al2O3(s)+ 2Fe(s) DrH° = -852 kJ

Using the following thermochemical equation,determine the amount of heat produced per kg of CO2 formed during the combustion of benzene (C6H6). 2C6H6(l)+ 15O2(g)→ 12CO2(g)+ 6H2O(g) DrH° = -6278 kJ

Choose the reaction that illustrates DfH° for Ca(NO3)2.

Use the standard reaction enthalpies given below to determine DrH° for the following reaction: 4SO3(g)→ 4S(s)+ 6O2(g) DrH°= ? Given: SO2(g)→ S(s)+ O2(g) DrH°= +296.8 kJ 2SO2(g)+ O2(g)→ 2SO3(g) DrH°= -197.8 kJ

How much heat is absorbed/released when 40.00 g of NH3(g)reacts in the presence of excess O2\mathrm { O } _ { 2 }O2​ (g)to produce NO(g)and H2O(l)according to the following chemical equation? 4NH3(g)+ 5O2(g)? 4NO(g)+ 6H2O(l) Δr\Delta _ { \mathrm { r } }Δr​ H° = 1168 kJ

What volume of benzene (C6H6,d = 0.88 g mL-1,molar mass = 78.11 g mol-1)is required to produce 1.5 × 103 kJ of heat according to the following reaction? 2C6H6(l)+ 15O2(g)→ 12CO2(g)+ 6H2O(g) DrH° = -6278 kJ

Identify an energy source that is non-renewable.

A bomb calorimeter with a heat capacity of 13.9 kJ °C-1 has an initial temperature of 21.9 °C.If 5.00 g of propanal (C3H6O,molar mass = 58.0791 g mol-1,DrU = -1822.7 kJ mol-1 for combustion)is combusted,calculate the final temperature of the calorimeter.

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Filters

At constant pressure,the combustion of 20.0 g of C₂H₆(g)releases 1036 kJ of heat.What is ?H for the reaction given below? 2C₂H₆(g)+ 7O₂(g)? 4CO₂(g)+ 6H₂O(l)

Use the _DfH°° and _DrH°information provided to calculate _DfH° for IF: 7(g)+(g)\rightarrow(g)+2 IF (g)=-89 (g) -941 (g) -840

Using the following equation for the combustion of octane,calculate the amount of grams of carbon dioxide formed from 100.0 g of octane.The molar mass of octane is 114.33 g mol^-1.The molar mass of carbon dioxide is 44.0095 g mol^-1. 2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O D_rH°= -11018 kJ

Calculate the heat transfer,in J,when 5.00 g of chromium (specific heat capacity = 0.449 J g^-1 °C^-1)at 0.00 °C is placed in 50.0 mL of water.The final temperature of the water is 23.8 °C.The chromium is defined as the system in this scenario.

Determine the final temperature of a gold nugget (mass = 376 g)that starts at 398 K and loses 4.85 kJ of heat to a snowbank when it is lost.The specific heat capacity of gold is 0.128 J g^-1 °C^-1.

Use the standard reaction enthalpies given below to determine _DrH° for the following reaction: P₄(g)+ 10Cl₂(g)? 4PCl₅(s) _DrH°0= ? Given: PCl₅(s)? PCl₃(g)+ Cl₂(g) $D _ { \mathrm { r } }$ H°= +157 kJ P₄(g)+ 6Cl₂(g)? 4PCl₃(g) $D _ { \mathrm { r } }$ H° = -1207 kJ

How much energy is evolved during the formation of 98.7 g of Fe according to the reaction below? Fe₂O₃(s)+ 2Al(s)→ Al₂O₃(s)+ 2Fe(s) D_rH°= -852 kJ

Using the following thermochemical equation,determine the amount of heat produced per kg of CO₂ formed during the combustion of benzene (C₆H₆). 2C₆H₆(l)+ 15O₂(g)→ 12CO₂(g)+ 6H₂O(g) D_rH°= -6278 kJ

Choose the reaction that illustrates _DfH° for Ca(NO₃)₂.

Use the standard reaction enthalpies given below to determine _DrH° for the following reaction: 4SO₃(g)→ 4S(s)+ 6O₂(g) _DrH°= ? Given: SO₂(g)→ S(s)+ O₂(g) _DrH°= +296.8 kJ 2SO₂(g)+ O₂(g)→ 2SO₃(g) _DrH°= -197.8 kJ

How much heat is absorbed/released when 40.00 g of NH₃(g)reacts in the presence of excess $\mathrm { O } _ { 2 }$ (g)to produce NO(g)and H₂O(l)according to the following chemical equation? 4NH₃(g)+ 5O₂(g)? 4NO(g)+ 6H₂O(l) $\Delta _ { \mathrm { r } }$ H° = 1168 kJ

What volume of benzene (C₆H₆,d = 0.88 g mL^-1,molar mass = 78.11 g mol^-1)is required to produce 1.5 × 10³ kJ of heat according to the following reaction? 2C₆H₆(l)+ 15O₂(g)→ 12CO₂(g)+ 6H₂O(g) D_rH°= -6278 kJ

A bomb calorimeter with a heat capacity of 13.9 kJ °C^-1 has an initial temperature of 21.9 °C.If 5.00 g of propanal (C₃H₆O,molar mass = 58.0791 g mol^-1,D_rU = -1822.7 kJ mol^-1 for combustion)is combusted,calculate the final temperature of the calorimeter.