Chemical Reactions #3

A change in color is a sign that what is taking place?

• chemical reaction

• chemical absorption

• molecular model

• word equation

The changes that are visible during a chemical reaction are signs that what is being rearranged in the reactants?

• electrons

• atoms

• products

• nuclei

A chemical reaction that transfers energy from the reactants to the surroundings is referred to as

• exothermic

• endothermic

• paleothetic

• exergonic

What type of reaction has the reactant broken down into other substances?

• synthesis

• decomposition

• combustion

• single replacement

What is the mole ratio in the following equation? $4Fe\ +\ 3O_2\ \rightarrow\ 2Fe_2O_3$  

• 2:3:4

• 3:4:2

• 1:2;4

• 4:3:2

What type of reaction is energy transferred from the surroundings to the reactants

• exothermic

• polyatomic

• endothermic

• polygenic

In a chemical reaction atoms are

• rearranged

• created

• destroyed

• dissolved

In a combustion reaction, what must always be a reactant?

• water

• hydrogen

• oxygen

• sodium

What type of reaction involves the transfer of electrons?

• free radical

• redox

• combustion

• synthesis

Which of the following is NEVER used to balance an equation?

• coefficients

• subscripts

• atoms

• electrons