Must Know Chemistry Terms

Question 1

Solution(Homogenous)

Answer 1

Also known as a homogenous mixture, has a uniform composition through out meaning, that they different atoms that make up the mixture can not be seen with the naked eye. Instead we only see the same colour of the mixture.

Question 2

Heterogenous Mixture

Answer 2

A mixture in which the composition is not uniform.

Question 3

Qualitative physical properties

Answer 3

Properties that enable you to observe with your senses (colour, lustre, texture, Odour etc) and don’t have a numerical value.

Question 4

Quantitative physical properties

Answer 4

Properties that you can measure/ give a numerical value too (Mass, Volume, Temperature, and density).

Question 5

Physical change

Answer 5

A change that affects the physical appearance but not the composition + changes can be reversed(Example, cutting, melting, breaking glass, boiling water).

Question 6

Chemical change

Answer 6

Changes that affect the composition of matter, and can’t be reversed(Cooking, Burning, Rusting, Rotting).

Question 7

Chemical change clues

Answer 7

1. Change in colour
2. Formation of gas(bubbles)
3. Change in light and heat
4. Formation of precipitate(Solid) in solution
5. Can’t be reversed

Question 8

Octet

Answer 8

Atoms tend to gain or lose electrons, in order to achieve a stable octet(8 valence electrons in the outer most shell of the atom).

Question 9

Ion

Answer 9

An atom or molecule that has lost or gain one or more of its valence electrons, giving it a negative or positive charge.

Question 10

Molecule

Answer 10

Is two or more atoms chemically bonded together.

Question 11

Pure substances

Answer 11

Are substances that are only made up of one kind of particle, has a fixed structure and can’t be separated into 2+ substances by chemical means.