Reactions Unit 5 Review

What type of reaction is this?

2H2 + O2 -> 2H2O

• Decomposition

• Double Replacement

• Combustion

• Synthesis

What type of reaction is this?

NiCl2 -> Ni + Cl2

• Synthesis

• Decomposition

• Acid Base

• Single Replacement

When balancing chemical equations, these #s can be changed...

• subscripts

• coefficients

• subscripts and coefficients

• you cannot change any numbers

When the following chemical reaction is balanced, what coefficient is placed before Fe? _Fe + 3O2-> 2Fe2O3

• 2

• 3

• 4

• 5

What type of reaction is this?

BaCl2 + KIO3 -> BaIO + KCl

• Single Replacement

• Acid Base

• Combustion

• Double Replacement

A chemical reaction in which heat energy is released is ____.

• a formula

• exothermic

• flammable

• endothermic

Which of the following could represent a decomposition reaction?

• element + compound = element + compound

• element + element = compound

• compound = element + element

• compound + compound = compound + compound

When methane (CH₄) burns, the main products are

• carbon dioxide

• water

• heat

• carbon dioxide, water, heat

A substance that is insoluble in water and comes out of solution indicating a chemical reaction has occurred. 

• precipitate

• catalyst

• endothermic

• formula

According to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants?

• The mass of products is sometimes greater.

• there is no relationship

• the masses are always equal

• the mass of the reactants is greater