Chemical Reactions Review

Mass is never lost or gained in chemical reactions. This is called .....?

• Balancing reactions

• Conservation of matter

• Conservation of mass

A chemical change is different than a physical change because in a chemical change

• chemicals are used

• molecules do not physically touch

• a new substance is formed and in a physical no new substance is formed

• the change can be seen but in a physical change it cannot

Tags

NGSS.MS-PS1-2

Which of the following 2 are chemical reactions?

• sugar dissolving in water

• water turning into steam

• burning wood

• mixing baking soda and vinegar

• tearing paper

Tags

NGSS.MS-PS1-2

Why are chemical equations always balanced? Select ALL that apply.

• Matter cannot be created.

• Matter cannot be destroyed.

• Matter can only be rearranged/conserved.

• Matter doesn't matter.

Tags

NGSS.MS-PS1-5

In a chemical reaction, if the reactants are heated, the reaction usually happens

• slower

• faster

• at the same rate

• in a smaller volume

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Some chemical reactions require a substance called a catalyst. The purpose of a catalyst is

• to warm up the reaction

• to speed up the reaction

• to create more reactants

• to stop the reaction

Tags

NGSS.MS-PS1-2

What does it mean for a reaction to be endothermic? Choose 2 of the following.

• When two substances react, the temperature of the mixture decreases.

• When two substances react, the temperature of the mixture increases.

• There is less energy going into the reactant to break the bond than there is energy leaving the product.

• There is more energy going into the reactant to break the bond than there is energy leaving the product.

• The amount of energy entering and leaving is the same.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

What does it mean for a reaction to be exothermic? Choose 2 of the following.

• When two substances react, the temperature of the mixture decreases.

• When two substances react, the temperature of the mixture increases.

• There is less energy going into the reactant to break the bond than there is energy leaving the product.

• There is more energy going into the reactant to break the bond than there is energy leaving the product.

• The amount of energy entering and leaving is the same.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Is this chemical equation balanced? Why or why not? Choose the BEST answer.

• Yes, the amount of atoms for each element are equal on both the reactant and product side.

• No, the carbons are not the same number on both the reactant and product side.

• No, neither the carbons or hydrogens are the same amount on both the reactant and product side.

• No, none of the elements (carbon, hydrogen, or oxygen) are the same amount on both the reactant and product side.

Tags

NGSS.MS-PS1-5

Which of the following is a common sign that a chemical change has occurred?

• A chemical has turned a different color, bubbled, and/or changed temperature.

• A chemical has changed to a different state of matter, such as a liquid to a solid.

• A chemical has changed size.

• A chemical has become a different shape.

Tags

NGSS.MS-PS1-2