Chemical reactions

Chemical reactions change substances into different substances by

• breaking and forming chemical bonds

• strengthening electrical charges of substances.

When hydrogen and oxygen combine to form water, water is

• a product

• a reactant

What is the process that changes one set of substances into another set of substances?

• activation energy

• chemical reactions

• hydrogen bonding

A candle burning because the wick is flammable.

• physical property

• chemical property

Q. 

The powder is blue.

• Physical Property

• Chemical Property

 

When the two substances combined, a reaction happened causing bubbling and fizzing.

• chemical property

• physical property

 

Water boils at 100 degrees Celsius.

• Physical property

• Chemical Property

How many hydrogen atoms are there in a water molecule? 

• 0

• 2

• 3

• 4

You have a large glass of water and you stir salt into it until all the salt completely dissolves.

• Chemical Reaction

• Physical Change

Which one shows that a chemical reaction has occurred?

• dissolving

• formation of a gas

• melting

• bending