PS-3rd 9wk exam

What is NOT evidence of a chemical reaction?

• Change in size

• Change in temperature

• Change in color

• A change in smell

A mole is a unit of

• weight
• Quality

• Quantity

• volume

How many moles of hydrogen are there in this reaction? N₂ + 3H₂ —> 2NH₃

• 2

• 3

• 1

• 0

A key feature of a single-replacement reaction is that:

• products and reactants both have a compound and element

• The reaction results in the formation of a new compound.
• The reaction does not involve any element replacement.
• Two elements replace each other in a compound.

What type of reaction requires oxygen?

• Fermentation
• Photosynthesis
• Combustion
• Decomposition

Catalysts increase reaction rates by

• lowering the activation energy
• slowing down the reaction
• increasing the activation energy
• decreasing the concentration of reactants

An example of a chemical change is boiling water.

• False
• True
• Freezing water
• Mixing salt and water

Substances produced as a result of a chemical reaction are called reactants

• True

• False

• Sometimes

Reactions with a SINGLE product are:

• Redox reactions
• Synthesis reactions

• Double replacement reactions

• Decomposition reactions

Gasoline burning in a car engine is an example of an exothermic reaction.

• Maybe
• False
• Partially true
• True