Chemical Reactions

Which of the following is NOT a chemical property?

• state of matter

• photosensitivity

• combustability

• flammability

_______ is a characteristic of a material that can be observed without actually changing the identity of the substance.

• a chemical property

• a physical property

• Activation Energy

• decomposition

Which of the following would NOT necessarily be considered evidence of a chemical change?

• one or more substances change state (liquid to gas, etc)

• a mixture bubbles and foams without a heat source

• a mixture forms a precipitate

• a mixture becomes hot without a heat source

Tags

NGSS.MS-PS1-2

According to _______, matter is neither destroyed nor created during a chemical reaction.  This is why we have to balance equations.

• the Law of Conservation of Mass

• Newton’s Law

• the Law of Chemical Reactions

• the Law of Conservation of Energy

Tags

NGSS.MS-PS1-5

In a chemical reaction, (aq) written after a compound means that:

• the compound is flammable.

• the compound is dissolved in water.

• the compound will melt.

• the compound is unstable.

The smallest amount of energy needed for a chemical reaction to begin is called its _______.

• activation energy

• excess reactant

• endothermicity

• limiting reactant

How many reactants are shown in the following chemical equation?

2H₃PO₄  +  3CaCO₃  -->  Ca₃(PO₄)₂  +  3H₂O  +  3CO₂

• 3

• 7

• 2

• 5

Tags

NGSS.MS-PS1-1

Changing the subscript in a chemical formula changes _______.

• nothing

• the identify of the substance so that it becomes a different compound

• the electrical charge on the atoms of that substance

• the amount of that substance

What CAN a chemical equation tell you?

• The conditions necessary, such as sunlight.

• The ratio of the substances involved in the reaction.

• If the reaction will occur.

• How fast the reaction will occur.

Tags

NGSS.MS-PS1-5

A solid compound that forms and settles out of a solution during a double displacement reaction is called _______.

• an aqueduct

• a catalyst

• a precipitate

• a reactant