Elements, compounds, mixtures

Question 1

Elements

Answer 1

A substance that has the same type of particle

Question 2

Compound

Answer 2

A substance that has elements that are chemically bonded to a different element

Question 3

Mixture

Answer 3

A mixture is made from different substances that are not chemically bonded

Question 4

Rules for naming compounds (3)

Answer 4

1. The element that comes first in the formula comes first.
2. If there are only two elements in the compound then the compound’s name ends in –ide
3. If the compound contains three elements one of which is oxygen then the compound name will end in –ate or –ite.

Question 5

Chemical formulae (CO2)

Answer 5

The chemical formula of carbon dioxide is CO2, we come to know that one carbon atom and two oxygen atoms are chemically bonded together to form one molecule of the compound, carbon dioxide

Question 6

What are the gases that are consisted in the air (and %)

Answer 6

• Nitrogen (78%)
• Oxygen (21%)
• Carbon Dioxide (0.04%)
• Other gases that are mostly argon (0.96)

Question 7

Hazards of acids

Answer 7

• Acids are corrosive. They can attack metals and destroy skin if spilled.

Question 8

Hazards of alkali

Answer 8

• It may be harmful if inhaled, ingested, or absorbed through the skin.
• Adding too much baking soda in a cake (alkali) can make it taste like soap