Thermochemistry 2

Benzoic acid, C₇H₆O₂, is a standard used in determining the heat capacity of a calorimeter. ΔH° of combustion of benzoic acid is 3.22 x10₃ kJ/mol. 0.5 g of benzoic acid was burned in a calorimeter containing 1000.0 g of water. The change in temperature of the calorimeter was 3^oC. Calculate the heat capacity of the calorimeter in J/K.

• 450 J/K

• 210 J/K

• 4025 J/K

• 2307 J/K

Tags

NGSS.HS-PS3-4

• -1429 kJ

• -733 kJ

• 733 kJ

• -1143 kJ

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

• −150kJ

• −75kJ

• 70kJ

• 10kJ

Tags

NGSS.HS-PS1-4

 $Reaction$   $S\left(s\right)+O_2\left(g\right)\rightarrow SO_2\left(g\right)\ \ \ \Delta H=-296\ kJ$ 
Given the following equation, which of the following statement(s) is (are) true?
I.The reaction is exothermic 
II.When 0.500 mol sulfur is reacted, 148 kJ of energy is released 
III.When 32.0 g of sulfur is burned, 2.96 x 105 J of energy is released

• All are true    

• None is true

• I and II are true

• I and III are true

• Only II is true

Tags

NGSS.HS-PS1-4

• A

• B

• C

• D

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-4

The heat capacity of a bomb calorimeter was determined by burning 6.79 g of methane (heat of combustion = −802 kJ/mol) in the bomb. The temperature changed by 10.8^oC.

a. What is the heat capacity of the bomb?

b. A 12.6-g sample of acetylene, C₂H₂, produced a temperature increase of 16.9^oC in the same calorimeter. What is the heat of combustion of acetylene (kJ/mol)?

Tags

NGSS.HS-PS1-4

A 5.037 g piece of iron heated to 100.^oC is placed in a coffee cup calorimeter that initially contains 27.3 g of water at 21.2^oC. If the final temperature is 22.7^oC, what is the specific heat capacity of the iron (J/g^oC)?

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Remember to give the calculation process involved. (example: number the equation as equation 1, equation 2, equation 3 as order in the question.

equation 1 = equation 2 - 2 x equation 3 is the calculation process )

Tags

NGSS.HS-PS1-4

Enthalpy is a state function, which means the enthalpy only depends on the substance and the conditions.

• Ture

• False

For the same substance, the quantity of ΔH_fusion is exactly the same as ΔH_condensation with different signs.

• Ture

• False