CHEM 2: E-Learning (1/28/2019)

A material is cooled from 100ºC to 40ºC.

What is the temperature change?

• 60ºC

• 40ºC

• -60ºC

• -40ºC

The specific heat of a metal is 0.21 J/g°C.

Calculate the heat when a 10 g piece of this metal is taken out of the oven and cools from 100°C to 50°C?

• 105 J

• 10.5 J

• -105 J

• -10.5 J

In an exothermic process, the surroundings are are gaining energy.

• True

• False

In an endothermic reaction the system is releasing energy.

• True
• False

A sample of iron receives 50.0 J of heat energy that raises the temperature of the iron 25.0°C.

If iron has a specific heat of 0.100 J/g°C, what is the mass of the iron sample?

• 25.0 g

• 30.0 g

• 20.0 g

• 50.0 g

372 J of heat is applied to a 1200 g steel pan with a specific heat of 0.23 J/g^oC.

How much does the temperature increase?

• 11,000 ^oC

• 1.6 ^oC

• 1.3 ^oC

Convert 6 cal into joules

• 1.43 J

• 6000 J

• 25.1 J

• 0.006 J

If 238 J of heat is absorbed by a sample of metal with a mass of 40.7 g, and it raises the temperature from 20.0°C to 32.4°C, what is the specific heat capacity of the metal?

• 2.34 J/g°C

• 0.472 J/g°C

• 6.13 J/g°C

• 0.163 J/g°C

A pot of 2400 g of water at a temperature of 25^oC is heated on a stove until the water boils (100^oC). The specific heat of water is 4.18 J/(g^oC).

Calculate the heat needed to heat the water in the pot to boiling.

• 133.76 J

• 43,062.2 J

• 752,400 J

• 1,003,200 J

If a piece of copper is heated from 23⁰C to 52⁰C, what is the value of ΔT?

• 29^oC

• -29^oC

• 75^oC

• none of these