Thermochemistry Problems

What would be the effect on the particles if more heat is supplied to the system?

• They would slow down
• They would stop moving
• They would speed up
• There would be no effect

A sample of iron receives 50.J of heat energy that raises the temperature of the iron 25.0°C. If iron has a specific heat of  0.10 J/g°C, what is the mass of the iron sample?

• 25 g
• 30 g
• 20 g
• 50 g

The specific heat is the amount of energy needed to raise the temperature one degree Celsius of 1 gram of a substance.

• True
• False

Water has a specific heat of 4184 J/KgºC.  Wood has a specific heat of 1760 J/KgºC.  What material needs more energy to raise the temperature 1ºC

• Wood
• Water
• Both are the same

A high specific heat means...

• It heats up quickly with energy added
• It requires more energy to change temperature

Calculate the heat absorbed by 105.0 grams of water when it is heated to cook spaghetti. The initial temperature of the water is 20.0°C, and the final temperature of the water is 99.0°C. The specific heat of water is 4.18 J/g•°C.

• 8778 J/g°C
• 0.0005 J/g°C
• 34673 J/g°C
• 43451.1 J/g°C

The temperature of an unknown piece of metal with a mass of 30.00 g changes from 25.0 °C to 35.0 °C when the metal absorbs 350.0 J of energy. What is the specific heat of the metal?

• 1.17 J/g°C
• -1.17 J/g°C
• 0.857 J/g°C
• -0.857 J/g°C

Cold Pack on Person

• Heat is transferred from the cold pack to the person.

• Heat is transferred from the person to the cold pack

• The cold pack is getting colder. The person is getting warmer.

The specific heat of copper is 0.385 J/g·°C. Which equation set up below would you use to calculate the amount of heat needed to raise the temperature of 0.75 g of copper from 7°C to 29°C?

• Q = 0.385 J/g·°C x (22°C)

• Q = 0.75 g x 0.385 J/g·°C x (7°C – 29°C)

• Q = 0.75 g x 0.385 J/g·°C x (29°C – 7°C)

• Q = 0.75 g x 0.385 J/g·°C x (29°C + 7°C)

Heat always moves from an object of __________ temperature to an object of _________ temperature.

• moderate, high
• higher, lower
• lower, higher
• zero, high