Introduction Chemistry

Chemistry is defined as the study of

• modern history

• physical phenomena

• matter and its changes

• motion and forces

Elements can be broken down into simpler substances by ordinary chemical means.

• false

• ture

• sometimes

The air is a _________. 

• element

• mixture

• atom

• compound

Which is an example of a chemical change ?

• glass breaking

• water freezing

• water evaporating

• paper burning

Which of the following is not a compound?

• HCl

• NaCl

• He

• HF

Which is the atomic symbol of hydrogen

• H

• O

• N

• S

Which is the atomic symbol of lithium

• L

• Li

• K

• Cl

What elements are contained in carbon dioxide

• C、H

• C、N

• C、O

• N、O

Which is the atomic symbol of beryllium

• Ba

• B

• Be

• Br

Which is the atomic symbol of helium

• H

• He

• Ne

• Al