Definitions

Question 1

Exothermic

Answer 1

Chemical reaction that gives out heat energy.

Question 2

Endothermic

Answer 2

Chemical energy that draws in heat energy.

Question 3

Diffusion rate

Answer 3

Process of which particles mix by colliding randomly with each other and bouncing off in various directions.

Question 4

Sublimation

include an example

Answer 4

In which a gas goes straight to a solid and vice versa. It doesn’t go through a liquid state

E.G.
CO2

Question 5

Melting point

Answer 5

The temperature of which a solid becomes a liquid.

Question 6

Boiling point

Answer 6

The temperature of which a substance boils.

Question 7

Isotope

Answer 7

Atoms of the same element that have a different number of neutrons.

Question 8

Element

Answer 8

A substance that can’t be split into anything simpler in a chemical reaction.

Question 9

Valency

Answer 9

Number of electrons on the outer shell of an atom.

Question 10

Molecule

Answer 10

Two or more atoms help together by covalent bonds.

Question 11

Ion

Answer 11

Particle with an uneven number of protons and electrons. (They have a charge)

Question 12

Compound

Answer 12

A substance in which 2 or more elements are chemically combined.

Question 13

Aqueous

Answer 13

A solution in which H2O is the solvent.

Question 14

Combining power/valency

Answer 14

The number that tells you how many electrons an atom gains/loses in order to form a compound.

Question 15

Empiricle formula

E.G
Ethene?

Answer 15

This is the simplest fixed ratio if atoms present in the compound.

Ethene = CH2

Question 16

Molecular formula

E.G
Ethene?

Answer 16

This is the actual formula of the compound.

Ethene = C2H4

Question 17

Catalyst

Answer 17

A substance that speeds up a chemical reaction without being used up in the process itself.

Question 18

Activation energy

Answer 18

The minimum amount of energy needed for a reaction to occur.