Chemistry

Question 1

What are the rules of electronic configuration?

Answer 1

1.) The first electron shell holds 2 electrons
2.) The second shell holds 8 electrons
3.) The third shell also holds 8 electrons

Question 2

What method is used to extract very reactive metals (such as potassium, sodium and aluminium) from ores?

Answer 2

Electrolysis.

Question 3

What two metals are found pure in the ground?

Answer 3

Silver and gold.

Question 4

What method is used to extract zinc, iron and copper from ores?

Answer 4

Displacement reaction with carbon.

Question 5

What is the test for oxygen?

Answer 5

Oxygen relights a glowing splint.

Question 6

What is the test for hydrogen?

Answer 6

Hydrogen makes a squeaky pop with a lighted splint.

Question 7

What is the test for chlorine?

Answer 7

Chlorine bleaches damp blue citrus paper.

Question 8

What is the test for carbon dioxide?

Answer 8

Take a test tube of limewater, if carbon dioxide is present then limewater will cahange colour from clear/colourless to cloudy/milky.

Question 9

Define an atom.

Answer 9

the smallest stable part of an element.

Question 10

Define an element.

Answer 10

something made up of one type of atom.

Question 11

Define a compound.

Answer 11

More than one element chemically bonded together.

Question 12

Define a mixture.

Answer 12

More than one element combined but not chemically bonded together.

Question 13

What methods can be used to separate mixtures?

Answer 13

Filtration
Distillation
Chromatography
Fractional Distillation

Question 14

What are the names for the following acids?
HCl
HNO3
H2SO4
H3PO4

Answer 14

HCl - Hydrochloric Acid
HNO3 - Nitric Acid
H2SO4 - Sulphuric Acid
H2CO3 - Carbonic Acid
H3PO4 - Phosphoric Acid

Question 15

Complete the sentences:
Group 1 elements form ___
Group 2 elements form ____
Group 3 elements form ____
Group 5 elements form ____
Group 6 elements form ____
Group 7 elements form ____

Answer 15

1 + ions
2+ ions
3 + ions
3 - ions
2 - ions
1 - ions

Question 16

What are the formulae for the following ions:
hydroxide
nitrate
carbonate
sulphate
phosphate
ammonium

Answer 16

HO -
NO3 -
CO3 2-
SO4 2-
PO4 3-
NH4 +

Question 17

Why are atoms always neutrally charged?

Answer 17

Atoms will always be neutral as the amount of positively charged protons and negatively charged electrons are always equal.

Question 18

Complete this equation:
number of neutrons =

Answer 18

mass no. - atomic number

Question 19

mass number =

Answer 19

no. protons + no. neutrons

Question 20

no. protons =

Answer 20

atomic number

Question 21

What was John Dalton’s theory about particles?

Answer 21

He suggested the there was tiny particles called atoms which were like tiny spheres that could not be divided.

Question 22

what did J J Thomson discover and what was his model of the atom called?

Answer 22

discovered the electron
suggested the plum pudding model.

Question 23

how did Rutherford test the plum pudding model and what happened?

Answer 23

by firing alpha particles at thin gold foil
some hit the nucleus and deflected back

Question 24

what did Rutherford’s experiment show?

Answer 24

The mass of an atoms is concentrated in the nucleus
The nucleus repelled the alpha particles showing the nucleus must be of a positive charge.

Question 25

what did Neils Bohr suggest?

Answer 25

suggested that the electrons must orbiting the nucleus at set distances

Question 26

what did Neils Bohr discover?

Answer 26

the proton.

Question 27

what did Chadwick discover/

Answer 27

the neutrally charged particle, the neutron.

Question 28

what are isotopes?

Answer 28

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

Question 29

relative atomic mass (Ar) =

Answer 29

total mass of all atoms / total number of atoms

Question 30

what does the law of conservation state?

Answer 30

the total mass of reactants equals total mass of product (matter cannot be created or destroyed).

Question 31

what is oxidation?

Answer 31

when metals become tarnished via reacting with oxygen from the air to form metal oxides.

Question 32

how do we obtain a metal from a metal oxide?

Answer 32

to obtain the metal, we must carry out the reverse process and remove the oxygen. this process is called reduction.

Question 33

when metals react, they ...

Answer 33

give away electrons.

Question 34

what happens in a displacement reactions?

Answer 34

a more reactive metal will displace a less reactive metal

Question 35

why does gold not need to be extracted from ores?

Answer 35

due to its low reactivity, it is already pure.

Question 36

what is an ore?

Answer 36

an ore is a rock containing metal oxides.

Question 37

what is the difference between a pure metal and an alloy?

Answer 37

a pure metal made up of one type of metal atom alloy made up of at least one metal and one non metal atom.

Question 38

why are alloys harder than pure metals?

Answer 38

the non-metal atoms prevent other atoms from shifting.

Question 39

what is phytomining?

Answer 39

plant certain plants on low- grade copper ores that absorb metal compounds from soil.

Question 40

what is smelting?

Answer 40

copper ore is obtained from the ground and heated in a furnace.

Question 41

what is bioleaching?

Answer 41

some bacteria can obtain their nutrients from copper compounds found in copper ores.

Question 42

what is corrosion?

Answer 42

the wearing away of any metal via reaction with oxygen and water forming metal oxides.

Question 43

what is rusting?

Answer 43

the corrosion of iron ONLY

Question 44

how can you prevent rusting?

Answer 44

by coating it in paint oil/grease plastic a less reactive metal a more reactive metal

Question 45

what is crude oil?

Answer 45

a mixture of hydrocarbons with different chain lengths.

Question 46

define saturated in terms of alkanes

Answer 46

only contain single carbon-carbon bonds

Question 47

define unsaturated in terms of alkanes

Answer 47

must be at least one carbon-carbon bond.

Question 48

define a hydrocarbon

Answer 48

a molecule made up of only carbon and hydrogen atoms.

Question 49

define the homologous series

Answer 49

families of compounds with the same general formula.

Question 50

alkanes are...

Answer 50

a homologous series of saturated hydrocarbons with the general formula C n H 2n+2 where n is the number of carbons.

Question 51

what is the molecular formula of methane

Answer 51

CH4

Question 52

C2H6 =

Answer 52

ethane

Question 53

C3H8 =

Answer 53

propane

Question 54

C4H10 =

Answer 54

butane

Question 55

describe the process of fractional distillation of crude oil.

Answer 55

crude oil is heated until it is vaporised. it is then fed into the fractionating column the fractionating column is built on a heat gradient, being hottest at the bottom and coolest at the top. Smaller molecules have lower boiling points and therefore they rise through the column until they condense and are collected at their boiling points. the crude oil is a mixture of hydrocarbons and therefore these mixtures will condense at different boiling points, producing separate fuels.