Chemistry

Question 1

Structure of an atom

Answer 1

An atom has a central nucleus. This is surrounded by electrons arranged in shells.

Question 2

Electron

Answer 2

Negative charge and very small

Question 3

Proton

Answer 3

Positive charge and same size as neutron

Question 4

Neutron

Answer 4

Neural charge and same size as proton

Question 5

Where is the majority of mass of an atom located?

Answer 5

Nucleus

Question 6

Atomic Number

Answer 6

The number of protons (smaller number)

Question 7

Mass number

Answer 7

The number of protons and neutrons (bigger number)

Question 8

Isotope

Answer 8

Same number of protons and electrons but different number of neutrons

Question 9

Concept of relative atomic mass

Answer 9

Weighted mean of masses of the atoms of isotopes.

Question 10

Calculating Ar

Answer 10

Total mass of atoms/Total percentage

Question 11

Where are periods?

Answer 11

Horizontal rows

Question 12

Where are groups?

Answer 12

Vertical columns

Question 13

How are elements ordered?

Answer 13

In order of increasing atomic number

Question 14

Group 1

Answer 14

Alkali metals

Question 15

Group 2

Answer 15

Alkaline earth metals

Question 16

Group 16

Answer 16

Common non-metals

Question 17

Group 17

Answer 17

Halogens

Question 18

Group 18

Answer 18

Noble gases

Question 19

Transition metal properties

Answer 19

Conduct electricity in solid and liquid states

Shiny when freshly cut

Question 20

Transition metals compared to group 1 metals

Answer 20

Higher melting points
Higher density
Greater strength
Greater hardness

Question 21

Electron configuration

Answer 21

Atomic number (protons)

Question 22

What happens down a metal group?

Answer 22

Reactivity increases

Question 23

What happens down a non-metal group?

Answer 23

Reactivity decreases

Question 24

What do elements in the same group have in common?

Answer 24

Similar chemical properties

Question 25

Can the nuclei be created or destroyed?

Answer 25

No

Question 26

State symbol (S)

Answer 26

Solid

Question 27

State symbol (L)

Answer 27

Liquid

Question 28

State symbol (G)

Answer 28

Gas

Question 29

State symbol (AQ)

Answer 29

Aqueous solution

Question 30

What is an equilibrium?

Answer 30

A situation where forward and back reactions happen at the same rate, and the concentration of substances stay the same.

Question 31

Factors that affect equilibrium

Answer 31

Concentration of reactants/products Temperature Overall pressure

Question 32

How do you use Ar to work out Mr? Use CO2 as an example

Answer 32

Example CO2: Ar of C = 12 | Ar of O = 16 12+16+16 = 44 Mr of CO2 = 44

Question 33

What is Avogadro’s number?

Answer 33

The number of particles in one mole of a substance

Question 34

What value is Avogadro’s constant?

Answer 34

6.02 x 10^23

Question 35

What is one mole of a substance?

Answer 35

Ar or Mr in grams

Question 36

How to work out percentage composition?

Answer 36

Total Ar of element/Mr of compound | x100

Question 37

What is empirical formula?

Answer 37

Simplest integer ratio of atoms

Question 38

Conditions for ideal gas

Answer 38

One mole of gas occupies a set volume at a given temperature or pressure. (24dm^3)

Question 39

What is concentration measured in?

Answer 39

mol dm ^-3 or g dm^-3

Question 40

Saturated Solution

Answer 40

A solution that contains the maximum amount of solute taht is capable of being dissolved.

Question 41

Titration calulations

Answer 41

Watch youtube video

Question 42

Percentage yield

Answer 42

``` Actual yield(g)/Predicted yield(g) X100 ```

Question 43

Oxidation

Answer 43

Gain of oxygen

Question 44

Reduction

Answer 44

Removal of oxygen

Question 45

Oxidation in terms of electron

Answer 45

Gain of electrons

Question 46

Reduction in terms of electron

Answer 46

Removal of electrons

Question 47

How to identify oxidation only?

Answer 47

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Question 48

How to identify reduction only?

Answer 48

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Question 49

How to identify a redox (both oxidation and reduction) ?

Answer 49

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Question 50

How to identify a non-oxidation/reduction?

Answer 50

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Question 51

Oxidising agent

Answer 51

Normally non-metal or positive ion

Question 52

Reducing agent

Answer 52

Normally metal or negative ion

Question 53

Element

Answer 53

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

Question 54

Compound

Answer 54

A substance made up of 2 or more elements chemically bonded

Question 55

Mixture

Answer 55

Consists of 2 or more substances, not chemically bonded

Question 56

What do atoms often react to form?

Answer 56

Compounds that have an election configuration of a noble gas (group 18)

Question 57

Ionic bonding

Answer 57

Metals and non-metals reacting leading to electrons going from metals to non-metals.

Question 58

Anion

Answer 58

Gains electrons and becomes negatively charged

Question 59

Cation

Answer 59

Loses electrons and becomes positively charged

Question 60

NH4+

Answer 60

Ammonium

Question 61

Ca2+

Answer 61

Calcium

Question 62

Na+

Answer 62

Sodium

Question 63

Pb2+

Answer 63

Lead

Question 64

OH-

Answer 64

Hydroxide

Question 65

NO3-

Answer 65

Nitrate

Question 66

CO3^2-

Answer 66

Carbonate

Question 67

SO4^2-

Answer 67

Sulfate

Question 68

What do roman numerals after an element suggest?

Answer 68

When an element has more than 1 oxidation state, the roman numerals denote which is present e.g. iron (lll)

Question 69

Physical properties of Ionic compounds

Answer 69

High boiling and melting points Solid at room temp Cannot conduct electricity in solid state Can conduct in molten or in solution state Strong electrostatic forces Hard and brittle

Question 70

Covalent bonding

Answer 70

Bonding between 2 non-metals (sharing of electrons)

Question 71

Covalent molecules can be...

Answer 71

Small molecules or giant structures

Question 72

Small covalent molecules

Answer 72

Water (H20) Ammonia (NH3) Methane (CH4)

Question 73

Giant covalent structures

Answer 73

Diamond (C) Graphite (C) Silicon dioxide (SiO2)

Question 74

Physical properties of small covalent molecules

Answer 74

Low melting and boiling points Does not conduct electricity (Strong covalent bonds, weak intermolecular forces)

Question 75

Physical properties of giant covalent properties

Answer 75

Very high melting points | Variable electricity conductivity (Diamond doesn't, graphite does and silicon is midway)

Question 76

Metallic bonding

Answer 76

The strong electrostatic force of attraction between metal ions

Question 77

What do solid metals exist as?

Answer 77

Solid metals exist as a giant structure of positively charged ions surrounded by delocalised electrons.

Question 78

Physical properties of metals

Answer 78

``` Shiny High melting and boiling points Good conductor of heat and electricity High density Malleable and ductile ```

Question 79

Where are intermolecular forces and how do you overcome them?

Answer 79

They exist between molecules and must be overcome in melting and boiling.

Question 80

Physical and chemical properties of alkali metals (group 1)

Answer 80

Physical - soft (can be cut with a knife) and low melting points Chemical -