Properties of Chemical Reactions

Front

Which is a statement of the law of conservation of mass?

Back

The total mass before a chemical reaction is the same as the total mass after the reaction.

Front

When a substance undergoes a chemical change, its identity does not change.

Back

False

Front

Which of the following is an example of a chemical change? bending a pop can, evaporating of milk, melting wax, burning paper

Back

burning paper

Front

An example of a chemical change is ____.

Back

frying a hamburger

Front

Which of the following is an example of a chemical reaction?

• lighting a match
• dissolving salt into water
• freezing water
• breaking a glass

Back

lighting a match

Front

A change in color is evidence of a __ change.

Back

chemical

Front

Which statement best describes the two demonstrations?

Back

Demonstration 1 showed a chemical change because a new gaseous substance was formed, and demonstration 2 showed a physical change because liquid water became water vapor.

Front

How many atoms of carbon, hydrogen, and oxygen make up the products for the combustion reaction between one molecule of methane (CH₄) and two molecules of oxygen (O₂)?

Back

1 carbon, 4 hydrogen, and 4 oxygen