Question 1

Identify a substance that is in a non-standard state.

Accepted Answer

A)  O2
B)  Ca
C)  H
D)  Zn
E)  Ne C

Question 2

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water.The measured temperature decreased from 23.8 °C to 22.7 °C.Identify the unknown salt.The specific heat of water is 4.184 J g-1 °C-1,and assume the density of the solution is 1.00 g mL-1.

Accepted Answer

A)  NaF,  DrD _ { \mathrm { r } }Dr​  H = 0.91 kJ mol-1
B)  NaBr,  DrD _ { \mathrm { r } }Dr​  H = -0.60 kJ mol-1
C)  NaNO3,  DrD _ { \mathrm { r } }Dr​  H = 20.50 kJ mol-1
D)  LiNO3,  DrD _ { \mathrm { r } }Dr​  H = -2.51 kJ mol-1
E)  LiBr?2H2O,  DrD _ { \mathrm { r } }Dr​  H = -23.26 kJ mol-1  A

Question 3

Use the information provided to determine $\Delta$r H° for the following reaction: $$\begin{array} { l l l l } 
 { \mathrm { D } _ { \mathrm { f } } H ^ { \circ } \left( \mathrm { kJ } \mathrm { mol } ^ { - 1 } \right) } & \mathrm { CH } _ { 4 } ( g ) + 3 \mathrm { Cl } _ { 2 } ( g ) \rightarrow \mathrm { CHCl } _ { 3 } ( l ) + 3 \mathrm { HCl } ( g ) & \Delta _ { \mathrm { r } } H ^ { \circ } = ? \
\mathrm { CH } _ { 4 } ( g )  & - 75 \
\mathrm { CHCl } _ { 3 } ( l )  - 134 & & \
\mathrm { HCl } ( g )  - 92 &
\end{array}$$

Accepted Answer

A)  -151 kJ mol-1
B)  -335 kJ mol-1
C)  +662 kJ mol-1
D)  +117 kJ mol-1
E)  -217 kJ mol-1  B

Question 4

Identify what a bomb calorimeter measures.

Accepted Answer

A)  measures ΔH for aqueous solutions
B)  measures ΔU for combustion reactions
C)  measures ΔH for oxidation solutions
D)  measures ΔT for hydrolysis solutions
E)  measures ΔU for reduction reactions

Question 5

Energy that is associated with the position or composition of an object is called

Accepted Answer

A)  kinetic energy.
B)  thermal energy.
C)  potential energy.
D)  chemical energy.

Question 6

Identify a substance that is not in its standard state.

Accepted Answer

A)  CO(s) 
B)  Ba(s) 
C)  H2(g) 
D)  O2(g) 
E)  Ni(s)

Question 7

A 5.00 g sample of liquid water at 25.0 °C is heated by the addition of 145 J of energy.The final temperature of the water is ________ °C.The specific heat capacity of liquid water is $4.184 \mathrm {~J} \mathrm {~g} ^ { - 1 } \mathrm {~K} ^ { - 1 }$

Accepted Answer

A)  25.9
B)  146
C)  6.93
D)  -18.1
E)  31.9

Question 8

A piece of gold with a mass of 21.0 g was heated to 100.0 °C and placed inside a coffee cup calorimeter.The temperature of the water inside the calorimeter increased from 23.8 °C to 25.5 °C.The specific heat capacity of water is 4.184 J g-1 °C-1 and the specific heat capacity of gold is 0.129 J g-1 °C-1.Calculate the mass of water contained inside the calorimeter.

Accepted Answer

A)  28.4 g
B)  16.0 g
C)  21.0 g
D)  39.5 g
E)  32.9 g

Question 9

According to the following thermochemical equation,what mass of H2O (in g)must form to produce 975 kJ of energy? SiO2(s)+ 4HF(g)→ SiF4(g)+ 2H2O(l) 
DrH° = -184 kJ

Accepted Answer

A)  68.0 g
B)  102 g
C)  54.1 g
D)  191 g
E)  95.5 g

Question 10

A chemist wishes to calibrate a bomb calorimeter,so he combusts 7.529 g of D-galactose,ΔcombustionU = -15.48 kJ g-1,which causes a temperature change from 26.38 °C to 34.60 °C.What should the chemist report for the value of Ccal?

Accepted Answer

A)  24.34 kJ °C-1
B)  8.009 kJ °C-1
C)  14.18 kJ °C-1
D)  16.67 kJ °C-1
E)  9.170 kJ °C-1

Question 11

Calculate the mass of NH4ClO4,molar mass = 117.49 g mol-1,required to create a temperature change of -1.0 °C in a coffee cup calorimeter containing 115 mL of water.The enthalpy of solution for NH4ClO4 is 33.47 kJ mol-1.The specific heat of water is 4.184 J g-1 °C-1,and assume the density of the solution is 1.00 g mL-1.

Accepted Answer

A)  1.7 g
B)  3.2 g
C)  2.8 g
D)  4.0 g
E)  0.83 g

Question 12

A 21.8 g sample of ethanol (C2H5OH)is burned in a bomb calorimeter according to the following reaction.If the temperature rises from 25.0 °C to 62.3 °C,determine the heat capacity of the calorimeter.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 mol-1

Accepted Answer

A)  4.99 kJ °C-1
B)  5.65 kJ °C-1
C)  63.7 kJ °C-1
D)  33.1 kJ °C-1
E)  15.7 kJ °C-1

Question 13

A piece of uranium with a mass of 12.1 g and an initial temperature of 60.2 °C was placed inside a coffee cup calorimeter.The temperature of the water inside the calorimeter increased from 22.8 °C to 23.9 °C.The specific heat capacity of water is 4.184 J g-1 °C-1 and the specific heat capacity of uranium is 0.116 J g-1 °C-1.Calculate the mass of water contained inside the calorimeter.

Accepted Answer

A)  1.2 g
B)  26 g
C)  8.4 g
D)  17 g
E)  11 g

Question 14

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g $\mathrm { mol } ^ { - 1 }$ . Fe3O4(s)? 3Fe(s)+ 2O2(g) 
DrH° = +1118 kJ

Accepted Answer

A)  1.10 × 106 kJ
B)  2.38 × 102 kJ
C)  2.66 × 105 kJ
D)  1.12 × 103 kJ
E)  3.44 × 104 kJ

Question 15

Which of the following (with specific heat capacity provided)would show the smallest temperature change upon gaining 200.0 J of heat?

Accepted Answer

A)  50.0 g Al,CAl = 0.903 J g-1 °C-1
B)  50.0 g Cu,CCu = 0.385 J g-1 °C-1
C)  25.0 g granite,Cgranite = 0.79 J g-1 °C-1
D)  25.0 g Au,CAu = 0.128 J g-1 °C-1
E)  25.0 g Ag,CAg = 0.235 J g-1 °C-1

Question 16

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g-1 °C-1)initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

Accepted Answer

A)  34.1 °C
B)  17.6 °C
C)  -34.1 °C
D)  -17.6 °C
E)  -8.70 °C

Question 17

Which of the following processes is endothermic?

Accepted Answer

A)  the freezing of water
B)  the combustion of propane
C)  a hot cup of coffee (system) cools on a countertop
D)  the chemical reaction in a "hot pack" often used to treat sore muscles
E)  the vaporization of rubbing alcohol

Question 18

A 50.0 g sample of liquid water at 25.0 °C is mixed with 19.0 g of water at 87.0 °C.The final temperature of the water is ________°C.

Accepted Answer

A)  93.6
B)  13.0
C)  62.0
D)  36.1
E)  42.1

Question 19

Choose the reaction that illustrates DfH° for NaHCO3.

Accepted Answer

A)  Na(s) + H2(g) + C(s) + O2(g) → NaHCO3 (s) 
B)  Na+(aq) + HCO3 -1 (aq) → NaHCO3 (s) 
C)  Na+(aq) + H2O (l) + CO2 (g) → NaHCO3(s) 
D)  Na(s) + 1/2 H2(g) + C(s) + 3/2 O2(g) → NaHCO3 (s) 
E)  Na(s) + 2 H(g) + C(s) + 3 O(g) → NaHCO3(s)

Question 20

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g-1 °C-1)that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

Accepted Answer

A)  3.15 °C
B)  0.941 °C
C)  -13.5 °C
D)  8.49 °C
E)  5.23 °C

Exam 6: Thermochemistry

Identify a substance that is in a non-standard state.

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water.The measured temperature decreased from 23.8 °C to 22.7 °C.Identify the unknown salt.The specific heat of water is 4.184 J g^-1 °C^-1,and assume the density of the solution is 1.00 g mL^-1.

Identify what a bomb calorimeter measures.

Energy that is associated with the position or composition of an object is called

Identify a substance that is not in its standard state.

A 5.00 g sample of liquid water at 25.0 °C is heated by the addition of 145 J of energy.The final temperature of the water is ________ °C.The specific heat capacity of liquid water is $4.184 \mathrm {~J} \mathrm {~g} ^ { - 1 } \mathrm {~K} ^ { - 1 }$

According to the following thermochemical equation,what mass of H₂O (in g) must form to produce 975 kJ of energy? SiO₂(s) + 4HF(g) → SiF₄(g) + 2H₂O(l) D_rH°= -184 kJ

A chemist wishes to calibrate a bomb calorimeter,so he combusts 7.529 g of D-galactose,Δ_combustionU = -15.48 kJ g^-1,which causes a temperature change from 26.38 °C to 34.60 °C.What should the chemist report for the value of C_cal?

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe₃O₄? The molar mass of Fe₃O₄is 231.55 g $\mathrm { mol } ^ { - 1 }$ . Fe₃O₄(s) ? 3Fe(s) + 2O₂(g) D_rH°= +1118 kJ

Which of the following (with specific heat capacity provided) would show the smallest temperature change upon gaining 200.0 J of heat?

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

Which of the following processes is endothermic?

A 50.0 g sample of liquid water at 25.0 °C is mixed with 19.0 g of water at 87.0 °C.The final temperature of the water is ________°C.

Choose the reaction that illustrates _DfH° for NaHCO₃.

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g^-1 °C^-¹) that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

Exam 6: Thermochemistry

Identify a substance that is in a non-standard state.

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water.The measured temperature decreased from 23.8 °C to 22.7 °C.Identify the unknown salt.The specific heat of water is 4.184 J g-1 °C-1,and assume the density of the solution is 1.00 g mL-1.

Identify what a bomb calorimeter measures.

Energy that is associated with the position or composition of an object is called

Identify a substance that is not in its standard state.

A 5.00 g sample of liquid water at 25.0 °C is heated by the addition of 145 J of energy.The final temperature of the water is ________ °C.The specific heat capacity of liquid water is 4.184 J g−1 K−14.184 \mathrm {~J} \mathrm {~g} ^ { - 1 } \mathrm {~K} ^ { - 1 }4.184 J g−1 K−1

According to the following thermochemical equation,what mass of H2O (in g) must form to produce 975 kJ of energy? SiO2(s) + 4HF(g) → SiF4(g) + 2H2O(l) DrH° = -184 kJ

A chemist wishes to calibrate a bomb calorimeter,so he combusts 7.529 g of D-galactose,ΔcombustionU = -15.48 kJ g-1,which causes a temperature change from 26.38 °C to 34.60 °C.What should the chemist report for the value of Ccal?

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe3O4? The molar mass of Fe3O4 is 231.55 g mol−1\mathrm { mol } ^ { - 1 }mol−1 . Fe3O4(s) ? 3Fe(s) + 2O2(g) DrH° = +1118 kJ

Which of the following (with specific heat capacity provided) would show the smallest temperature change upon gaining 200.0 J of heat?

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g-1 °C-1) initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

Which of the following processes is endothermic?

A 50.0 g sample of liquid water at 25.0 °C is mixed with 19.0 g of water at 87.0 °C.The final temperature of the water is ________°C.

Choose the reaction that illustrates DfH° for NaHCO3.

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g-1 °C-1) that absorb 17472 J of heat while warming up to room temperature,23.1 °C.

10.618 g of an unknown salt is dissolved in a coffee cup calorimeter that contains 50.0 mL of water.The measured temperature decreased from 23.8 °C to 22.7 °C.Identify the unknown salt.The specific heat of water is 4.184 J g^-1 °C^-1,and assume the density of the solution is 1.00 g mL^-1.

A 5.00 g sample of liquid water at 25.0 °C is heated by the addition of 145 J of energy.The final temperature of the water is ________ °C.The specific heat capacity of liquid water is $4.184 \mathrm {~J} \mathrm {~g} ^ { - 1 } \mathrm {~K} ^ { - 1 }$

According to the following thermochemical equation,what mass of H₂O (in g) must form to produce 975 kJ of energy? SiO₂(s) + 4HF(g) → SiF₄(g) + 2H₂O(l) D_rH°= -184 kJ

A chemist wishes to calibrate a bomb calorimeter,so he combusts 7.529 g of D-galactose,Δ_combustionU = -15.48 kJ g^-1,which causes a temperature change from 26.38 °C to 34.60 °C.What should the chemist report for the value of C_cal?

According to the following reaction,how much energy is required to decompose 55.0 kg of Fe₃O₄? The molar mass of Fe₃O₄is 231.55 g $\mathrm { mol } ^ { - 1 }$ . Fe₃O₄(s) ? 3Fe(s) + 2O₂(g) D_rH°= +1118 kJ

Calculate the final temperature of 68.4 g of molecular hydrogen (specific heat capacity = 14.304 J g^-1 °C^-1) initially at 8.24 °C that releases 25.3 kJ of energy into the surroundings.

Choose the reaction that illustrates _DfH° for NaHCO₃.

Calculate the initial temperature of 448 g of grapes (specific heat capacity = 1.76 J g^-1 °C^-¹) that absorb 17472 J of heat while warming up to room temperature,23.1 °C.