C2 Flashcards

1
Q

What is the mass number in an atom

A

the total number of protons and neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the atomic number of an atom

A

The number of protons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do you find the number of neutrins in an atom

A

subtrace the atomic number from the mass number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How can you tell the atomic number frkm the mass number

A

the atomic number is never bigger than the mass number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are compountd formed

A

When atoms of two or more elements are chemically combined together

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

is it easy to seperare the atoms that have formed a compound

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are isotopes

A

different atomic forms of the same element, which have the same number of protons but a different number of neutrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens in ionic bonding

A

In ionic bonding, atoms lose or gain to form charges particles called ions which are then strongly attracted to one another because of the attraction of opposite charges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

when would a shell want to get rid of one or more electrons

A

when the electrons are less than half of the number of electrons it needs to have a full outer shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an ion

A

an atom with a full outer shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what lattice strusture do ionic compounds have and why are they strong

A

giant ionic lattices, they are strong because they have very strong forces electrostatic forces of attraction between oppositely charged ions, in all directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What similar properties do ionic compounds share?

A

they all have high melting points and hkgh boiling points due to the strong attraction between the ions. It takes a large ammount of energy to overcome this attraction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What happens when ionic compounds melt

A

they are free to move and theyll carry electric current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens when ions dissolve

A

the ions seperate and are all free to move in the solution, so theyll carry electric current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do ions and noble gases share

A

they bith have the same electronic structure with a full outer shell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which atom groups are most likely to form ions and why

A

group 1,2,6&7 , 1&2 because they are metals and lost electrons to form positive ions and group 6&7 elements are non-metals. They gain electrons to form negative ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are ionic compounds made up of

A

ionic compounds are made up of a positively charged part and a negatively charged part

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the overall charge of any compound

A

0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what structures do ionic compounds have

A

giant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what happens to the ions when an ionic compound melts

A

they are free to move, this allows them to carry electrical charge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is needed to overcome the ionic bonds to melt solids

A

a lot of energy

22
Q

why do ionic solids have high melting points

A

because alot of energy is needed to break the ionic bonds

23
Q

why can ionic substances conduct electricity when disolved in water or when molten

A

because the electrons are free to move

24
Q

what kind of bonds hold together the atoms in a molecule

A

strong covalent bonds

25
Q

why dont molecules carry electricity

A

because they have no overall charge

26
Q

why doesnt petrol conduct electricity

A

because it has no overall charge

27
Q

why are substances with large molecules more likely to be liquids at room temperature

A

the forces between molecules, called intermolecular forces, are weak, they overcome when a molecular substance melts or boils, so the substances with smaller molecules will have a low melting point

28
Q

why do giant covalent structures have high melting points?

A

because every atom is joined to several other atoms by strons covalent bonds, so it would take an enourmous ammount of energy to break them

29
Q

give 2 sililarities of graphite and diamond

A

they are both forms of carbon

they both have covalent bonds

30
Q

give 2 differences of diamond and graphite

A

diamond has covalent bonds between laters, graphite doesnt

diamond is transparent, graphite is not

31
Q

what are fullerines

A

large molecules formed from large hexagonal rings of carbon atoms, the rings join together to form cage like shapes with different numbers of carbon atoms, some of which are nano sized,

scientists are finding many uses for fullerines eg catalysts, drug delivery into the body and reinforcing metals

32
Q

why can metals be made into wires

A

because they are made in layers, this means the atoms can slide over oneanother, they can move into a new position without breaking

33
Q

give 2 reasons why alloys can be more useful than pure metals

A

they are harder than pure metals because the different sizes in atoms distort the layers, this means that they are harder than pure metals. Shape memory alloys can have their shape changes and they will bend back into their original shape

34
Q

why do LD and HD poly(ethene) have different properties

A

because they are made using different catalysts and different reactions

35
Q

What are the main differencrs in structures in thermosoftening and thermosetting polymers

A

Thermosoftening polymers are made up of individual polymer chains that are tangled together. Thermosetting polymers do not melt of soften when you soften them then you heat them

36
Q

what allows thermosoftening polymers to be remoulded

A

in thermosoftening polymers the forces between the polymer chains are weak. When they are heated, these weak intermolecular forces are broken and the polymer becomes soft. When the polymer cools down, the intermolecular forces bring the polymer molecules back together so the polymer hardens again

37
Q

what is a nanoparticle

A

particles that are a few nanometers in size

38
Q

how big is a nanometer

A

one billionth of a meter or 10 to the -9

39
Q

what is needed before nanoparticles are sold for use eg in deodrants

A

further research for safety

40
Q

why do we only count the protons and neutrons to calculate the mass of an atom

A

because the mass is almost entirely made up of protons and neutrons and electrons make very little difference

41
Q

what are isotopes

A

they are atoms of the same element with a different number of neutrons

42
Q

what is a mole

A

the relative atomic mass of atoms in the element

43
Q

how is the reletive atomic mass of a substance found

A

by adding all the relative atomic masses of the atoms in the formula

44
Q

how can we calculate the percentage of any of the elements in a compound

A

divide the reletive atomoc mass of the elelemt by the reletive formula mass of the compound and times it by 100 to convert it as a percentage

45
Q

what is the empiracle formula

A

the simplest ratio of atoms or ions in a compound, it is the formula used for ionic compounds

46
Q

how do you calculate the empiracle formula of a compound from its percentage composition

A

devide the mass of each element in 100 g of the compound by its A(r) to give the ration of atoms. Then convert this to the simplest whole number ratio

47
Q

what does the yield of a chemical reaction tell us

A

how much product is made compared to the maximum ammound that could be made

48
Q

why is it important to maximuse yield

A

to conserve earths resources and reduce pollution

49
Q

what is a reversable reaction

A

a reaction where the products of the reaction can react to make the original reactions

50
Q

what do we use paper chromatography to do

A

detect and identify artificial colours

51
Q

how do we identify food additives

A

chemical analysis