Unit 7 Test Review. quantity of heat needed to raise the temperature of 1 g of water by 1 C calorie.
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Transcript of Unit 7 Test Review. quantity of heat needed to raise the temperature of 1 g of water by 1 C calorie.
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