Unit 7

Test Review

quantity of heat needed to raise the temperature of 1 g of water by 1 C 

• calorie

SI unit of energy

• Joule

quantity of heat needed to change the temperature of 1 g of a substance by 1 oC 

 

• Specific heat

heat content of a system at constant pressure

• enthalpy

device used to measure the heat absorbed or released during a chemical or physical process

• calorimeter

the enthalpy change for a chemical reaction exactly as it is written

heat of reaction

the change in enthalpy that accompanies the formation of a compound from its elements

heat of formation

Hess's law of heat summation

states that if you add two or more thermochemical equations to give a final equation, you can also add the heats of reaction to give the final heat of reaction

the energy required to melt a solid at its melting point 

• heat of fusion

the enthalpy change caused by dissolving a substance 

• heat of solution

Describe the heat changes when piece of metal is heated, then submerged in cool water.

The temperature of the water will increase and the temperature of the metal will decrease.

What would the flask in which an endothermic reaction were occurring feel like?

• Cool to the touch

How is the transfer of heat measured?

• temperature changes

Who has greater bond energy in an exothermic reaction, the reactants or products?

• reactants

A process that absorbs heat is

• endothermic

How many kilocalories are in 3000 calories?

• 3 kilocalories (or Calories)

What does H stand for?

• the heat of reaction for a chemical reaction

How do we determine the enthalpy change for a reaction in an aqueous solution (what tool do we need?)

• Use a calorimeter

The amount of heat released by the complete burning of 1 mole of a substance is the ____.

• Heat of combustion

endothermic or exothermic?

• endothermic

When a solid changes to a liquid, why doesn’t the temperature change during the melting process?

• The heat energy is being used to change the phase

Why does water have such a high specific heat?

• Hydrogen bonds

Compare the energy released in the formation of a compound to the energy required to decompose that compound

• The energy changes are the same

products are at a higher energy level than are the reactantsendothermic or exothermic?

• endothermic

What is exchanged between the system and the surroundings in a closed system

• Energy only

What is exchanged between the system and the surroundings in an open system

• Energy and mass

What is exchanged between the system and the surroundings in an isolated system

• nothing

• Know how to do specific heat problems

• Know how do calculate enthalpy changes