Unit 10 Thermochemistry

A common material to use for a calorimeter is _.

• styrofoam

• metal

• glass

• plastic

For the formula:
 Q= m c ∆T
The  units for specific heat are:

• g /J C
• °C/g J
• kJ/g
• J/g°C

If two objects have different temperatures when they come in contact, heat will flow from the warmer object to the cooler one UNTIL ____________

• one reaches a temperature of zero

• they both have an equal temperature

• one runs out of energy

Calculation: If the specific heat of water is 4.18 J/g∙°C, how much heat is required to increase the temperature of 1,200 g of water from 23 °C to 39 °C?

• -80,256 J

• 80.256 J

• 80,256 J

• -80.256 J

Calculation: What is the specific heat of an unknown substance if 100.0 g of it at 200.0 °C reaches an equilibrium temperature of 27.1 °C when it comes in contact with a calorimeter of water.  The water weighs 75. g and had an initial temperature of 20.00 °C?  (Specific heat of water is 4.18 J/g°C) 

• 0.111 J/g°C
• 1.29 J/g°C
• 0.129 J/g°C
• 22225.85 J

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

• 25g
• 30g
• 20g
• 50g

A reaction is performed in a beaker with a temperature probe recording the temperature changes of the reaction.  If the temperature began at 15.0 degrees Celsius and ended at 27.5 degrees Celsius. Is the reaction endothermic or exothermic?

• Exothermic
• Endothermic

In an exothermic process, the surroundings are gaining energy.

• True
• False

What does "ΔT" mean?

• A change in health

• A change in heat

• A change in height

• A change in temperature

Specific heat of water is 4.18 J/g°C. Specific heat of wood is 1.760 J/g°C What material needs more energy to raise the temperature by 1 degree Celsius?

• Water

• Wood

• Both are same