EOY Flashcards

1
Q

Advantages of nanoparticles in suncream?

A

better coverage

more protection from the sun’s UV rays

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2
Q

Disadvantages of nanoparticles in suncream?

A

may cause potential cell damage to the body

could have harmful effects on the environment

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3
Q

Order of sizes

A

dm, cm , mm , um (micrometre), nm

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4
Q

Pure substance

A

a single element or single compound

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5
Q

What is the test for chlorine gas?

A

a damp litmus paper turns white

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6
Q

oxides of nitrogen cause

A

acid rain

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7
Q

particulate matter causes

A

global dimming

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8
Q

what is the relative mass of an electron?

A

very small

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9
Q

what is the relative mass of a proton and neutron?

A

1

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10
Q

Why are instrumental methods used to measure gas?

A

accurate

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11
Q

Compounds formed from only non-metals consist of particles called?

A

molecules

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12
Q

Compounds formed when non-metals react with metals consist of particles called?

A

ions

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13
Q

The relative formula mass of a substance, in grams, is one … of the substance

A

mole

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14
Q

Why did Mendeleev leave gaps?

A

for undiscovered elements

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15
Q

State two similarities between hydrogen and atoms in group 1?

A

they have 1 electron in their outer shell

forms ions with a 1+ charge

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16
Q

Describe how knowledge of the numbers of protons and electrons in atoms allow chemists to place elements in their correct order and correct group.

A

number of electrons = number of protons
chemical properties depend on the outer electrons
number of shells gives the period

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17
Q

There are no transition elements between the Group 2 element magnesium and the Group 3 element aluminium.
Give a reason why, in terms of electronic structure.

A

2nd shell can only have a maximum of 8 electrons

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18
Q

Suggest what predictions Mendeleev was able to make about these undiscovered elements.

A

predicted their properties

predicted that they were metals

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19
Q

Why is lithium less reactive than potassium, in terms of electronic structure?

A

outer shells are closer to the nucleus

stronger force of attraction between the outermost electron and the nucleus, less easily lost in reaction

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20
Q

State why transition metal oxides are added to pottery glazes

A

For colour

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21
Q

State two properties which coinage metals should have

A

hard - so they don’t get scratched

unreactive - so they don’t corrode

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22
Q

Explain 2 differences in the reactions of potassium and lithium with water

A

potassium
produces a lilac flame
melts and forms a ball

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23
Q

Give 3 properties of why alkali metals should be grouped together

A

they form ions with 1+ charge
they are very reactive
they react with water to form alkaline solutions

24
Q

How did Mendeleev improve John Newland’s periodic table and why?

A

he left gaps for undiscovered elements

so that the elements would fit into their proper groups

25
Q

alcohol + …. —> carbon dioxide + water

A

oxygen

26
Q

What is the functional group in an alcohol molecule?

A

OH-

27
Q

How do alkene molecules form a molecule of plastic?

A

double bond breaks

and the alkenes join together

28
Q

Not all molecules are compounds but …

A

all compounds are molecules

29
Q

Suggest 2 of the main costs of making a plastic from crude oil

A

energy is required

cost of crude oil

30
Q

Suggest two problems caused by the disposal of plastics in landfill sites

A

landfill sites are filling up

not biodegradable

31
Q

Plastics made from plants would be more environmentally friendly than plastics made from
crude oil, why?

A

Biodegradable

renewable resources

32
Q

Suggest a problem caused by plastics going to landfill sites.

A

there is not enough space in landfill sites

33
Q

How are resources saved by recycling more plastics

A

less crude oil is used

34
Q

Suggest why recycling, products made from C2H4 and C3H6 is difficult

A

two different polymers

35
Q

Why might repeats be conducted?

A

to improve accuracy
to calculate an average
to identify anomalous results

36
Q

Suggest why the student warmed the liquid hydrocarbon using warm water and not a
Bunsen flame.

A

it is flammable

37
Q

Crude oil is a …. of different substances

A

mixture

38
Q

Why should sulfur be removed from petrol?

A

sulfur produces sulfur dioxide

which cause acid rain

39
Q

What is metallic bonding?

A

is the electrostatic attraction between metal ions and a sea of ‘delocalised’ electrons

40
Q

Suggest how the use of a suspension of limestone decreases one of the environmental
impacts that the waste gases would cause

A

Sulfur dioxide and oxides of nitrogen both cause acid rain. They can be neutralised by calcium carbonate.

41
Q

Difference between a smart polymer and a regular polymer

A

a smart polymer can return to its original shape when conditions change

42
Q

Why is incomplete combustion of methane dangerous?

A

carbon monoxide is made

which combines with the haemoglobin and prevents oxygen from being carried in the blood

43
Q

Explain why, in terms of the energy involved in bond breaking and bond making, the combustion of methane is exothermic.

A

energy is required to break bonds
energy is released when bonds are made
more energy is released than energy taken in

44
Q

Why can graphine rub off?

A

layers have weak intermolecular forces

so they can slide over each other

45
Q

A nanodiamond contains a few … atoms

A

hundred

46
Q

What is made from chlorine?

A

bleach

47
Q

carbon particles cause

A

global dimming

48
Q

How is carbon dioxide removed from the atmosphere?

A

plants / trees absorb carbon dioxide

coal ‘locks up’ carbon dioxide

49
Q

How to measure volume of gas produced?

A

The reaction mixture is connected to a gas syringe where gas is collected

50
Q

rate of reaction =

A

volume of gas produced / time taken

51
Q

Rate if resction is measured in

A

cm3/s

52
Q

How to measure change in mass?

A

Reaction is placed on a mass balance

As reaction proceeds, mass of the flask decreases as gas is given off

53
Q

Rate of reaction for gas is

A

g/s

54
Q

Explain how metals can conduct electricity (4 marks)

A

Metals are giant lattices
that are made up of positive ions
with delocalised electrons
so electrons can move through the metal

55
Q

Describe how the structure of an alloy is different from the structure of a pure metal.

A

An alloy has different sizes of atoms

Alloys have distorted layers

56
Q

Why is nitinol used in dental braces?

A

can return to its original shape

57
Q

Explain why chlorine (Cl2) is a gas at room temperature, but sodium chloride (NaCl) is a solid at room temperature.

A
Chlorine
- covalent bonds between atoms
- forming simple molecules 
- so there is weak attraction between molecules
- therefore has a low boiling point
Sodium Chloride
- ionic bonds
- therefore strong bonds in all directions
- between oppositely charged atoms
- forming a giant lattice 
- so high boiling point