Thermochemistry Introduction

The release of chemical potential energy produces all of the following except:

• heat

• work

• motion

• cooling

Chemicals in gasoline contain a large amount of potential energy because:

• there are many compounds present in gasoline

• gasoline components carry out several reactions

• gasoline is very volatile

• there are many chemical bonds present

A unit of heat is the ________

• joule/sec

• joule/kg

• joule

• joule · gram/sec

In an exothermic process, the surrounding loses heat.

• True

• False

Do the reactants in an exothermic reaction have higher or lower energy than the products?

• Higher

• Lower

A slower particle has lower energy than an identical, faster particle.

• True

• False

Thermal energy always moves:

• From a high temperature object to a lower temperature object.

• From a lower temperature object to a higher temperature object.

• From an object with lower kinetic energy to an object with higher kinetic energy.

• From an object of higher mass to an object of lower mass.

Using your knowledge of stoichiometry, refer to the following question:

2N₂ + 3H₂ --> 2NH₃ + 46 kJ

How much energy would be produced if only 1 mol of nitrogen was reacted?

• 92 kJ

• 0.143kJ

• 23kJ

• 15kJ

The diagram shows what happens when zinc reacts with hydrochloric acid. Which of these best describes the energy transformation that occurs during this reaction?

• Thermal energy - kinetic energy

• Kinetic energy -potential energy

• Chemical energy - thermal energy

• Potential energy - chemical energy

What is the relationship between the total amount of energy at location A & E (without friction)?

• A has more total energy than E

• E has more total energy than A

• You cannot tell how much total energy they have

• A and E have the same amount of total energy