Thermochem Practice Test

Heat transfer moves...

• from cold areas toward hot areas

• downward

• from hot areas toward cooler areas

• none of these

Coffee cup calorimeters measure changes in

• pressure

• volume

• temperature

• all of these

Heating and cooling systems work best when using liquids that have __ specific heat.

• high

• medium

• low

• answers may vary

What is likely to be true about the ∆H for a reaction that cools from liquid to solid?

• ∆H > 0

• ∆H < 0

• ∆H = 0

• none of these

Forward and reverse reactions generally include the same ΔH (expressed in kJ or J)​ ​ (a)  

• True
• False

A chemical reaction is carried out in a closed container. = 150 kJ.

The energy "liberated" from the air or the walls of the container =

• 75 kJ

• 150 kJ

• -75 kJ

• -150 kJ

The term __ refers to measures of energy transferred from one object to another

• pressure

• mass

• thermometer

• heat

In a calorimeter, 10 g of ice melts at 0^oC. The enthalpy of fusion of the ice is 334 J/g.

How much heat was absorbed?

• 0.34 kJ

• 3.34 kJ

• 33.4 kJ

• 334 kJ

You have a series of four chemical reactions (1→2→3→4).

How do you calculate the ΔH3 if you know the other ΔH values?

ΔH3 = ΔH4 -

• (ΔH1 + ΔH2)

• (ΔH1 x ΔH2)

• (ΔH1 / ΔH2)

• (ΔH1 - ΔH2)

Consider these generic equations:

2X + 3Y→2Z, ΔH=?

2X + 2Y→2Z, ΔH=−600kJ

2Z + Y→2Z, ΔH=−200kJ  

What is the missing ΔH?

• 300 kJ

• -300 kJ

• 800 kJ

• -800 kJ