Fundimental Ideas In Chemistry

Question 1

Name three types state of matter and describe

Answer 1

Solid- Fixed particles, Cannot be compressed, vibrate
Liquid- Touching, Slide across eachother, cannot be compressed, no fixed shape
Gas- Move freely, Compressed easily, spread out

Question 2

Why does a pure substance have sharp melting and boiling point and mixture not?

Answer 2

Single substance has sharp melting point
Mixture of substance does not, e,g chocolate melts at 30° and 32° (broad melting point)

Question 3

What is melting?

Answer 3

When particles in a solid gain heat energy and vibrate more vigorously. Solid changes state and becomes liquid.

Question 4

What is condensation?

Answer 4

When particles in a gas lose heat energy and move slower. A gas changes state and becomes liquid.

Question 5

What is freezing?

Answer 5

When particles in a liquid lose heat energy, move less quickly. A liquid changes state and becomes solid.

Question 6

What is the relative charge and mass of an electron

Answer 6

Relative charge is -1
Relalive mass is small (0.0008)

Question 7

What is the relative charge and mass of protons?

Answer 7

Relative charge is +1
Relative mass is 1

Question 8

What is the relative charge and mass of nuetrons?

Answer 8

Nuetrons relative charge is 0
Nuetrons relative mass is 0

Question 9

What is the mass number?

Answer 9

Number on the top
Protons + nuetrons

Question 10

What is the atomic number?

Answer 10

Number on the bottem
Protons and electrons

Question 11

What is a group?

Answer 11

Column, numbers on the top of periodic table
1-7 with 0 on end

Question 12

What is a period?

Answer 12

Row,go across periodic table- 7 periods incuding hydrogen and helium

Question 13

What is the 2,8,8 structure?

Answer 13

First ring of electrons only have max 2, the rest have max 8

Question 14

What is an element?

Answer 14

A substance made of 1 type of atom that cannot be broken down into any other substance

Question 15

What is a compound?

Answer 15

A pure substance that is made from one or more elements chemically bonded togther, making it very difficult to separate them

Question 16

Name some simple compounds

Answer 16

Carbon dioxide- CO2- 1 carbon, 2 oxygen
Methane- CH4- 1 carbon, hydrogen
Sulphur dioxide- SO2- 1 sulphur, 2 oxygen
Water- H2O-2 hydrogen, 1 oxygen

Question 17

Define the term mole

Answer 17

Amount of a substance in the relative atomic or formula mass of a substance in grams

Question 18

What is avogarodros number

Answer 18

6.022X 10^23

Question 19

What is the mole equation?

Answer 19

Moles= mass (g) divided formula mass

Question 20

What is the relative formula mass equation

Answer 20

Mass number X number of atoms
E.g H2O= 1X2=2
16X1=16
16+2=18

Question 21

What is percentage by equation

Answer 21

% by mass = (Atomic number total) divide (formula mass) X100