Unit 1.1 - The Nature Of Substances And Chemical Reactions

Question 1

What is the mass number/Atomic mass/Ar

Answer 1

Mass of Protons + neutrons of an atom

Question 2

What are elements

Answer 2

Substances that cannot be broken down into simpler substances. They are substances made up of only one type of atom

Question 3

How to calculate atomic number

Answer 3

Number of protons/electrons

Question 4

How to calculate the Number of Neutrons

Answer 4

Mass number - atomic number

Question 5

What are isotopes

Answer 5

Isotopes are atoms of the same element with the same number of protons but a different number of neutrons

Question 6

What are compounds

Answer 6

Compounds are substances made of two or more different types of atoms that are chemically joined. Compounds Are difficult to separate

Question 7

True/false.
Compounds have the same properties to the elements that made it

Answer 7

False-the properties of compounds can be completely different to the elements that made it

Question 8

How to work out Ar /relative atomic mass
Example: chlorine
75% - 35 Cl
25% - 37 Cl

Answer 8

(75x35) + (25x37)
————————-
100

Question 9

How to work out formulae
Aluminium oxide

Answer 9

Al3+. O2-
Al2O3

Question 10

What does Mr stand for

Answer 10

Relative molecular mass

Question 11

How to work out Mr
H2O

Answer 11

2x1 + 1x16 = Mr of 18

Question 12

How to work out percentage composition by mass
Example: what percentage of NH3 is N

Answer 12

Mr(NH3)=17
1x14
—— x 100 = 82%
17

Question 13

What is a mixture

Answer 13

Adam/molecules in mixtures I’m not chemically joined therefore can be easily separated. Mixtures can be in any proportions and they do not lose their original properties.

Question 14

What physical processes can separate mixtures

Answer 14

Filtration, evaporation, chromatography, distillation

Question 15

Give a use for each method of separating a mixture
Evaporation, filtration, chromatography, distillation 

Answer 15

Evaporation = changes liquid into gas
Filtration = filtrate liquid from substance
Distillation = changes liquid into gas and collects gas
Chromatography = separates dyes

Question 16

What happens to atoms in a chemical reaction

Answer 16

Atoms are rearranged but none are created or destroyed, Therefore the mass of the reactants would be the same as the mass of the products

Question 17

Cheat for writing equations

Answer 17

Signs
know
workout
balance

Question 18

How to write equations
Example:
Magnesium + oxygen => Magnesium oxide

Answer 18

S. + =>
K. Mg + O2 =>
W. Mg + O2 => MgO
B. 2Mg + O2 => 2MgO

Question 19

Cheat for diatomic substances

Answer 19

Have no fear of ice cold beer
Hydrogen
Nitrogen
Fluoride
Oxygen
Iodine
Chlorine
Bromium

Question 20

Useful acid formulaes

Answer 20

Sulphuric acid-H2SO4
Nitric acid - HNO3
Hydrochloric acid HCl

Question 21

Four types of chemical reactions

Answer 21

Exothermic, endothermic, neutralisation, reversible

Question 22

Properties of types of chemical reactions
Exothermic, endothermic, neutralisation, reversible

Answer 22

Exothermic-gives of heat
Endothermic a-takes in heat (Cold on Surface)
Neutralisation-where acids and bases react to form neutral products
Reversible-can be reversed dependant on conditions

Question 23

Mass, atomic mass, moles triangle

Answer 23

Mass

Ar. Moles

Question 24

How to work out empirical formulae
Example : 0.62 g phosphorus combined with 0.48 g of oxygen

Answer 24

Elements P. O
Mass. 0.62. 0.48
Ar. 31. 16
Moles. 0.02. 0.03
Ratio. 2. 3
Formula. P2. O3

P2O3

Question 25

How to work out reacting masses Example: 2Mg + 02 => 2MgO

Answer 25

Elements. Mg. MgO Mass. 6. ? => 10 Ar. 24. 40 Moles. 0.25. X1>. 0.25 Ratio. 2. X1> 2

Question 26

What is the valency of an element

Answer 26

How many electrons are lost/gained when an atom turns into an ion

Question 27

What is an ion

Answer 27

An atom with an electrical charge

Question 28

What happens to turn an atom into an ion

Answer 28

An electron is lost/gained

Question 29

Two uses of gas chromatography

Answer 29

Find exact amount & see forged to banknotes

Question 30

Advantage of gas chromatography over paper chromatography

Answer 30

Tells the exact amount

Question 31

Explain why the process of chromatography is able to separate dyes

Answer 31

All the chemicals have different solubilities

Question 32

Equation for Rf

Answer 32

Distance from baseline to compound spot ———————————————————— = Rf Distance from baseline to solvent front

Question 33

Equation to work out the percentage yield

Answer 33

Theoretical mass ————————- x 100 = %yield Actual mass

Question 34

Reacting masses ratio

Answer 34

Always 1:1

Question 35

What is a period on the periodic table

Answer 35

Row

Question 36

What is a group on the periodic table

Answer 36

Column

Question 37

If an element is in group 2 what does it tell you about that element

Answer 37

It has two electrons in the outer orbit/shell

Question 38

If an element is in period two what does it tell you about that element

Answer 38

It has two electron orbits/shells in total

Question 39

How many electrons fit on its first orbit /shell

Answer 39

2

Question 40

How many electrons fit on every orbit/shell except the first

Answer 40

8

Question 41

If an element is in group 8/zero what does it tell you about that element

Answer 41

It has a full outer orbit/shell

Question 42

How to get number of electrons

Answer 42

Atomic number

Question 43

To get a number of protons

Answer 43

Atomic number

Question 44