C1 + C2 A

Question 1

Law of Conservation of Mass

Answer 1

Total mass of products = total mass of reactants

Question 2

How can the law of Conservation of Mass be broken?

Answer 2

In reactions involving gases, this law can appear to be broken when the reactions are carried out in open containers, like test tubes and conical flasks

Question 3

Solution

Answer 3

A mixture of a liquid(solvent) and one/more dissolved solids(solutes)

Question 4

Solvent

Answer 4

A liquid that dissolves certain solutes to make a solution

Question 5

Solute

Answer 5

A solid that can be dissolved in solvent to make a solution

Question 6

Soluble

Answer 6

Can be dissolved in a given solvent

Question 7

Insoluble

Answer 7

Cannot be dissolved in a given solution

Question 8

What separation technique is used for mixtures with liquids and insoluble solids?

Answer 8

Filtration

Question 9

How does filtration occur?

Answer 9

1) A mixture is poured into the filter funnel, which has folded filter paper, and is designed to let liquids pass through, but stop solids passing through

Question 10

What filtration technique separates a solvent from a solution?

Answer 10

Distillation

Question 11

Processes of distillation

Answer 11

1) The solution is poured into a round-bottomed flask, connected to a condenser in a closed system to prevent the loss of gases.
2) The solution is heated - the liquid solvent boils into a gas.
3) The gas cools and condenses in the condenser back into a liquid(distillate) collected, but the solid solute remains as residue on the inside of the round-bottomed flask.

Question 12

What collection technique would be used when the solute doesn’t break down at high temperatures?

Answer 12

Evaporation - separates the solute from a solution

Question 13

How does evaporation occur?

Answer 13

1) The solution is poured into an evaporating basin and heated.
2) The liquid solvent boils off, leaving the solid solute as residue in the evaporating basin

Question 14

What techniques separate a solute from a solution?

Answer 14

Evaporate
Crystallisation

Question 15

What collection technique is used when the solute will thermally decompose at high temperatures?

Answer 15

Crystallisation

Question 16

What happens in crystallisation?

Answer 16

The solution is gently heated in an evaporating basin, meaning liquid solvent evaporates and crystals form, which then are left to cool, so crystals of the solute form in the residual solution. Once cool, remaining solution is removed by filtration and the crystals are dried.

Question 17

What technique can be used to separate a mixture of two or more liquids with different boiling points?

Answer 17

Fractional distillation

Question 18

What technique is used to separate mixtures according to the solubility of the components?

Answer 18

Chromatography

Question 19

What does Dalton suggest about the history of the atom?

Answer 19

Atoms are tiny, hard spheres that can’t be divided or split
Also that each chemical element had its own atoms that differed from others in their mass

Question 20

What did JJ Thompson suggest about the history of the atom!

Answer 20

He suggested in an atom, there are tiny negatively charged electrons embedded in a cloud of positive charge, with atoms carrying no overall charge.

Question 21

What did Rutherford suggest about the history of the atom?

Answer 21

Electrons are orbiting around a mucleus, with dense positively charged protons

Question 22

What did Niels Bohr suggest about the atomic model?

Answer 22

Electrons orbit the nucleus at set distances, in certain fixed energy levels/shells

Question 23

What did James Chadwick suggest about the atomic model?

Answer 23

That the nucleus also contains the sub-atomic particle neutron - with no charge and the same mass of a proton, because this explained the missing mass noticed in atoms at the time.

Question 24

What’s the charge of the nucleus?

Answer 24

An overall positive charge, since it contains protons with a positive charge, but neutrons with no charge

Question 25

Atomic number

Answer 25

The number of protons in each atom of an element

Question 25

Where is the mass of an atom concentrated?

Answer 25

In the nucleus, protons and neutrons have the same relative mass(1), electrons are very light

Question 26

How are the elements in the periodic table arranged?

Answer 26

In order of their atomic number

Question 27

Ion

Answer 27

A charged atom/group of atoms

Question 28

Isotopes

Answer 28

Atoms of the same element with different numbers of neutrons

Question 29

What is the impact of extra neutrons on isotopes?

Answer 29

Extra neutrons make the nucleus unstable, so an isotope may he radioactive
Samples of different isotopes of an element have different physical properties(e.g. different density and level of radioactivity, but they have the same chemical properties as their atoms have the same number of protons + electrons).

Question 30

What is the lowest energy level shown by shells of electrons?

Answer 30

The lowest energy level is shown by the shell nearest to the nucleus and the electrons in an atom occupy the lowest available energy level, the highest energy level is shown by the outermost shell in an atom.

Question 31

What determines the way a particular element reacts?

Answer 31

The number of electrons in the outermost shell of an element’s atoms determine the way in which the element reacts and the overall chemical properties of an element

Question 32

Which liquid will be collected first in fractional distillation?

Answer 32

The liquid witn the lowest boiling point

Question 33

Paper chromatography

Answer 33

1) Draw a line near the bottom of a sheet of filter paper with a pencil(pencil marks are insoluble and won’t dissolve in the solvent).
2) Add a spot of the ink to the line and place the sheet in a beaker of dolvent e.g. water.
3) Ensure the ink isn’t touching the solvent - you don’t want to dissolve it.
4) Place a lid on top of the container to stop the solvent evaporating.
5) The solvent seeps up the paper, carrying the in, with it.
6) Each different dye in the ink will move up the paper at a different rate, s9 the dyes will separate out.
7) If any of the dyes in the ink are insoluble, they’ll stay on the baseline.
8) When the solvent’s nearly reached the top of the paper, take the paper out of the beaker and leave it to dry.
9) The end result is a pattern of spots called a chromatogram.