Elements, compounds and mixtures

Question 1

What are the three states of matter

Answer 1

Solid, liquid and gas

Question 2

What are the physical properties of solids

Answer 2

• high density
• cannot be compressed
• fixed shape
• cannot diffuse
• doesn’t exert any pressure

Question 3

What are the physical properties of a liquid

Answer 3

• fairly high density
• cannot be compressed
• takes up shape of the bottom of the container
• can diffuse
• can exert some pressure

Question 4

Physical properties of gases

Answer 4

• low density
• can be compressed
• no fixed volume or shape
• can diffuse
• exert a lot of pressure

Question 5

How do you get from a solid to a liquid and what is the name of the process

Answer 5

Melting - heat up the solid

Question 6

How do you get from a liquid to a solid and what is the name of the process

Answer 6

freezing - cooling down the liquid

Question 7

How do you get from a liquid to a gas and what is the name of the process

Answer 7

evaporation/boiling - heat up the liquid

Question 8

How do you get from a gas to a liquid and what is the name of the process

Answer 8

Condensing - cool down the gas

Question 9

How do you get from a solid to a gas and what is the name of the process

Answer 9

Sublimation - heat up the solid

Question 10

How do you get from a gas to a solid and what is the name of the process

Answer 10

sublimation - cooling down the gas

Question 11

Explain the reasoning behind the bromine diffusion experiment

Answer 11

the bromine diffuses up against gravity and filled the containers evenly. The bromine particles moved via collisions with each other

Question 12

What is a solvent

Answer 12

The liquid that does the dissolving

Question 13

What is a solute

Answer 13

The solid that dissolves

Question 14

What is a solution

Answer 14

A mixture that is made when a solute dissolves into a solvent

Question 15

What is a saturated solution

Answer 15

A saturated solution can dissolve no more solute in that amount of solvent AT THAT TEMPERATURE

Question 16

What does the term solubility in the units g per 100 g of solvent mean

Answer 16

The solubility of a solute in H2O at a given temperature is the maximum amount of it that it will dissolve in 100g of H2O at that temperature

Question 17

element definition

Answer 17

A substance that contains one type of atom only. it cannot be broken down into anything simpler

Question 18

compound definition

Answer 18

A substance that contains 2 or more different atoms CHEMICALLY BONDED

Question 19

Mixture definition

Answer 19

a substance that contains 2 or more different atoms NOT chemically bonded

Question 20

Atom definition

Answer 20

The smallest part of an element that can exist on its own and has the characteristics of that element

Question 21

What does filtration separate

Answer 21

Separating an insoluble solid from a liquid

Question 22

What does evaporation/cyrstallisation separate

Answer 22

separating a soluble solute from a solution

Question 23

What does simple distillation separate

Answer 23

Separates a solvent from its solution

Question 24

What does fractional distillation separate

Answer 24

separates different liquids from a mixture of liquids

Question 25

What does a separating funnel separate

Answer 25

Separates 2 immiscible liquids (e.g. water and oil)

Question 26

What does chromatography separate

Answer 26

Separates mixture of soluble solids/ separates a mixture of dyes

Question 27

What is the method for the chromatography experiment

Answer 27

1. Draw a pencil line on chromatography paper 2. Small spot of sample on pencil line; allow to dry 3. Place chromatography paper in a beaker containing solvent to a height lower then the pencil line 4. Place a lid on beaker 5. Allow solvent to run up the paper until near the top 6. measure the distance travelled by the solvent and the spots 7. find Rf values

Question 28

How do you calculate the Rf value

Answer 28

Distance travelled by substance (the dye) / distance travelled by solvent

Question 29

Explain why dyes travel different distances up the chromatography paper

Answer 29

If the dye has a strong affinity for the mobile phase (the solvent) the dye will move far up the paper, but if the dye has a strong affinity for the stationary phase the dye will move slower. If the dye doesn't move it means it is insoluble in that solvent

Question 30

What are the relative masses of protons, neutrons and electrons

Answer 30

Protons - 1 Neutrons - 1 Electron - 1/1840

Question 31

What are the relative charges of protons electrons and neutrons

Answer 31

Proton = +1 Electron = -1 Neutron = 0

Question 32

What is the atomic number

Answer 32

number of protons in the nucleus

Question 33

What is the atomic mass

Answer 33

number of protons and neutrons in the nucleus

Question 34

Isotope definition

Answer 34

Atoms of the same element with the same number of protons and electrons but different number of neutrons

Question 35

Why are isotopes chemically identical

Answer 35

They have the same number of electrons

Question 36

How is the periodic table ordered

Answer 36

atomic number

Question 37

How and why does does reactivity change going down the periodic table in Group 1

Answer 37

Reactivity increases. - when group 1 want to lose an electron - as you go down group 1 the outer electron is further away and more shieled from the positive nucleus - this makes it easier to lose the outer electron making it more reactive

Question 38

What are the similarities between group 1 metals when they reaction with water

Answer 38

They all: - Fizz/ effervesce - float - move on the surface - get smaller/ disappear

Question 39

What happens when the alkali metals Li, Na and K react with oxyegn

Answer 39

Li - burns with crimson/ red flame to form a white solid Na - burns with a yellow flame to form a white solid K - burns with a lilac flame to form a white solid

Question 40

What are the trends going down group 1

Answer 40

- Bigger atoms - more reactive - more dense - lower m.p and b.p - Softer to cut

Question 41

Covalent bonding definition

Answer 41

The strong electrostatic attraction between the nuclei and shared electron pairs

Question 42

Ionic bonding definition

Answer 42

The strong electrostatic attraction between oppositely charged ions

Question 43

What is formed when a group 1 metal reacts with water

Answer 43

metalhydroxide + hydrogen