gcse revision

Question 1

what is an isotope?

Answer 1

An isotope is an atom of the same element with the same number of protons but a different number of neutrons

Question 2

What is a covalent bond?

Answer 2

A covalent bond is the attraction between one pair of electrons and the nuclei of each atom.

Question 3

What is metallic bonding?

Answer 3

Metallic bonding is the strong electrostatic attraction between the negatively charged metal ions and the positively charged delocalised electrons.

Question 4

What is ionic bonding?

Answer 4

the electrostatic attraction between oppositely charged ions.

Question 5

what’s an ion?

Answer 5

an ion is an atom which has lost or gained electrons. loss is positive, gain is negative.

Question 6

what is a subatomic particle?

Answer 6

a particle smaller then an atom, protons neutrons and electrons

Question 7

what’s the link between the group number and the number of electrons on the outer shell?

Answer 7

The group number and the number of electrons on the outer shell are the same.

Question 8

What is the mass number and how do you work it out?

Answer 8

the number of protons plus the number of neutrons. to work out the mass number take the atomic number away from the mass number

Question 9

atomic number

Answer 9

the atomic number is the same as the amount of protons and electrons

Question 10

what is the iconic formula for aluminium chloride?

Answer 10

AlCl3 because aluminium has a 3+ charge and chlorine has a 1- charge. switch the numbers around

Question 11

what is the rhyme to remember the reactivity series?

Answer 11

Please Send Lions Cats Monkeys And Zebras Into Lovely Hot Countries, Sincerely General Penguin

Question 12

What is the reactivity series?

Answer 12

Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Lead Hydrogen Copper Silver Gold Platinum

Question 13

what is a hydrocarbon?

Answer 13

a CHEMICAL COMPOUND containing HYDROGEN and CARBON only

Question 14

What is the molecular formula of methane?

Answer 14

CH4 - 4 hydrogen atoms and 1 carbon atom

Question 15

What’s an isomer?

Answer 15

a COMPOUND with the SAME MOLECULAR FORMULA but a DIFFERENT DISPLAYED FORMULA

Question 16

How many hydrogen and carbon atoms does butane have?

Answer 16

C4H10 - 4 carbon atoms 10 hydrogen atoms

Question 17

why do we break down crude oil?

Answer 17

Because on its own it isn’t useful so you break it down into different more useful fractions using fractional distillation

Question 18

what are some properties of long chained hydrocarbons?

Answer 18

high viscosity (hard to be poured)
high melting and boiling point 
low flammability 
dark in colour 
low volatility (doesn’t turn into gas easily)

Question 19

what are some properties of short chained hydrocarbons?

Answer 19

low viscosity (can be poured easily) 
low melting and boiling points 
high flammability 
high volatility (turns into a gas easily) 
light/colourless

Question 20

what is crude oil?

Answer 20

a type of FOSSIL FUEL

made of lots of DIFFERENT HYDROCARBONS

Question 21

what is the general formula of an alkane?

Answer 21

CnH2n+2

Question 22

what is the general formula of alkenes?

Answer 22

CnH2n

Question 23

what does complete combustion produce?

Answer 23

complete combustion produces CAEBON DIOXIDE and WATER

Question 24

What does incomplete combustion produce?

Answer 24

Incomplete combustion produced CARBON MONOXIDE and WATER or CARBON and WATER

Question 25

What does viscous mean?

Answer 25

To have a thick or sticky consistency, hard to pour

Question 26

whats a polymer?

Answer 26

polymers are large molecules nade up of small repeating units (monomers)

Question 27

What if the general formula for alcohol?

Answer 27

CnH2n+1+OH

Question 28

What is the homologous series?

Answer 28

A homologous series is a family of hydrocarbons with similar chemical properties who share the same general formula.

Question 29

How do you test for ammonia gas?

Answer 29

turns damp litmus paper red to blue

Question 30

What is the test for copper || ?(flame test)

Answer 30

Turns flame blue green

Question 31

What is the test for copper ||?

Answer 31

Add sodium hydroxide and it makes a blue precipitate

Question 32

What is the test for lithium ions? Flame

Answer 32

Turns flame red

Question 33

What is the test for sodium? Flame

Answer 33

Turns the flame yellow

Question 34

What’s the test for potassium ions? flame

Answer 34

Turns the flame lilac

Question 35

what is the test for calcium ions? flame

Answer 35

the flame goes orange red

Question 36

what is the test for iron ||| ions?

Answer 36

sodium hydroxide brown precipitate

Question 37

what is the test for iron|| irons?

Answer 37

sodium hydroxide, goes moss green

Question 38

What’s the test for ammonium ions?

Answer 38

sodium hydroxide, ammonia gas produced, test gas with red litmus paper, turns blue

Question 39

How do you test for carbonates?

Answer 39

Add hydrochloric acid, fizzes, test the gas with lime water to prove its carbon dioxide

Question 40

How do you test for sulfates?

Answer 40

Add dilute hydrochloric acid, add barium chloride solution, white precipitate produced

Question 41

How do you test for chlorides?

Answer 41

Add dilute nitric acid and silver nitrate solution and a white precipitate is formed

Question 42

How do you test for bromide?

Answer 42

Add dilute nitric acid and silver nitrate solution and a cream precipitate is formed

Question 43

How do you test for iodides?

Answer 43

Add dilute nitric acid and silver nitrate solution and a yellow precipitate is formed

Question 44

How do you test for chlorine gas?

Answer 44

it bleaches damp litmus paper

Question 45

what is an exothermic reaction?

Answer 45

A reaction that releases thermal energy to the surroundings (hot)

Question 46

what is an endothermic reaction?

Answer 46

A reaction that takes in thermal energy from the surroundings (cold)

Question 47

What is activation energy?

Answer 47

Activation energy is the minimum amount of energy the reactant particles require in order to collide with each other and react

Question 48

What is the general formula for alkanes?

Answer 48

CnH2n+2

Question 49

What is the general formula for alkenes?

Answer 49

CnH2n

Question 50

What hydrocarbons have double bonds?

Answer 50

Alkenes (unsaturated)