Unit 8 Exam_Thermochemistry

How does a calorie compare to a joule?

• A calorie is smaller than a joule.

• A calorie is larger than a joule.

• A calorie is equal to a joule.

• The relationship cannot be determined.

What would likely happen if you were to touch the flask in which an endothermic reaction were occurring?

• The flask would probably feel cooler than before the reaction started

• The flask would probably feel warmer than before the reaction started.

• The flask would feel the same as before the reaction started.

• none of the above

In an exothermic reaction, the energy stored in the chemical bonds of the reactants is ____.

• equal to the energy stored in the bonds of the products

• greater than the energy stored in the bonds of the products

• less than the energy stored in the bonds of the products

• less than the heat released

A process that absorbs heat is a(n) ____.

• endothermic process

• exothermic process

• polythermic process

• ectothermic process

The quantity of heat required to change the temperature of 1 g of a substance by 1C is defined as ____.

• a joule

• specific heat

• a calorie

• density

On what principle does calorimetry depend?

• Hess's law

• law of conservation of energy

• law of enthalpy

• law of multiple proportions

A 4.0 g sample of iron was heated from 0ºC to 20.ºC. It absorbed 35.2 J of energy as heat. What is the specific heat of this piece of iron?

• 2816 J/(g·ºC)

• 2.27 J/(g·ºC)

• 2.27 J/g

• 0.44 J/(g·ºC)

How much energy does a copper sample absorb as energy in the form of heat if its specific heat is 0.384 J/(g·ºC), its mass is 8.00 g, and it is heated from 10.0ºC to 40.0ºC?

• 0.0016 J/(g·ºC)

• 0.0016 J

• 92.2 J

• 92.2 J/(g·ºC)

Find the specific heat of a material if a 6.0 g sample absorbs 50,0 J when it is heated from 30ºC to 50ºC.

• 0.60 J

• 0.60 J/(g·ºC)

• 0.42 J

• 0.42 J/(g·ºC)

How much energy is absorbed as heat by 20.0 g of gold when it is heated from 25ºC to 35ºC? The specific heat of gold is 0.13 J/g·ºC.

• 26 J

• 26 J/(g·ºC)

• 0.0006 J

• 0.0006 J/(g·ºC)