Review - Chemical Reactions

What is the general formula for a combustion reaction?

• Fuel + O2 → CO2 + H2O

• A + B → AB

• AB + CD → AD + CB

• AB → A + B

What type of reaction is the burning of wood?

• Synthesis

• Decomposition

• Exothermic

• Endothermic

Tags

NGSS.MS-PS1-4

NGSS.MS-PS1-5

What type of reaction absorbs energy from the environment?

• Exothermic

• Endothermic

• Combustion

• Synthesis

Tags

NGSS.MS-PS1-4

What is a sign of an exothermic reaction?

• Absorption of heat

• Release of heat or light

• Formation of a gas

• Color change

What happens to reactants during a chemical reaction?

• They disappear

• They transform into products

• They remain unchanged

• They become elements

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is NOT a sign of a chemical reaction?

• A) Change in temperature

• B) Formation of bubbles

Tags

NGSS.MS-PS1-2

What is formed when a solid settles out of a liquid solution during a reaction?

• Precipitate

• Gas

• Product

• Catalyst

Tags

NGSS.MS-PS1-2

What do coefficients in a chemical equation indicate?

• A) The temperature of the reaction

• B) The number of molecules involved

• C) The state of the reactants

• D) The type of reaction

Tags

NGSS.MS-PS1-1

What do coefficients do in a chemical equation?

• A) They increase the number of molecules

• B) They increase the number of atoms in a reaction

• C) They have the same effect as subscripts

• D) They are multiplied by the number of subscripts in the molecules to increase the number of atoms in a molecule.

Tags

NGSS.MS-PS1-1

What do subscripts in a chemical formula describe?

• A) The type of reaction

• B) The number of atoms of an element

• C) The state of the compound

• D) The energy changes