Module 2 - Foundations in Chemistry - Exam Questions Flashcards

1
Q

Define relative isotopic mass (2)

A

Mass of the isotope compared to 1/12th of the mass of a carbon 12

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

Define isotopes (1)

A

Atoms with 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
3
Q

Explain why isotopes have the same chemical properties (1)

A

Same number of electrons in the outer shell

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

Define relative atomic mass (3)

A

The weighted mean mass of an atom relative to 1/12th the mass of one atom of carbon 12

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

How could the fraction of the isotopes of carbon be found experimentally? (1)

A

Mass spectrometry

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

Explain what is meant by a salt (1)

A

When the H+ in an acid is replaced by a metal ion

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

What term is given to the .n H2O part of a formula? (1)

A

Waters of crystallisation

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

What calcium compound is formed when calcium oxide reacts with water? (1)

A

Calcium hydroxide

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

What calcium compound is formed when calcium oxide reacts with nitric acid? (1)

A

Calcium nitrate

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

How do old samples of magnesium oxide become contaminated with magnesium carbonate? (1)

A

MgO has reacted with CO2

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

A student adds an excess of HCl to magnesium oxide and magnesium carbonate, state two observations that would be made (2)

A

Solid dissolves

Effervescence

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

Define an acid (1)

A

A proton donor

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

How can CaCO3 be used to combat excess stomach acid? Use an equation (2)

A

CaCO3 neutralises HCl

CaCO3 + 2HCl -> CaCl2 + H2O + CO2

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

State an important use of ammonium sulphate (1)

A

Fertiliser

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

State a large-scale use of ammonia (1)

A

Manufacture of explosives

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

Use oxidation numbers to explain why the reaction involves both oxidation and reduction (algebraically) (3)

A

X: oxidation number goes up
Y: oxidation number goes down
X is oxidised and Y is reduced

17
Q

Explain, in terms of electrons, what is meant by oxidation (1)

A

Loss of electrons

18
Q

What is meant by the term mole? (1)

A

Amount of substance that has the same number of particles as there are atoms in 12g of carbon 12

19
Q

What is a common use of NaClO? (1)

A

Bleach

20
Q

Define empirical formula (1)

A

Simples whole number ratio of atoms

21
Q

After Ca has fully reacted with HCl, upon adding more Ca, a reaction still takes place, why? (3)

A

Ca has reacted with water

Ca + 2H2O -> Ca(OH)2 + H2

22
Q

Explain what is meant by molecular formula (1)

A

Number and type of atoms making up a molecule

23
Q

What is meant by ionic bonding? (1)

A

Electrostatic attraction between oppositely charged ions

24
Q

Predict the bond angle in an F2O molecule and explain (3)

A

104.5
There are 2 bonded pairs and 2 lone pairs
Lone pairs repel more than bonded pairs

25
Q

Describe and explain two anomalous properties of water from hydrogen bonding (4)

A

Liquid H2O is more dense than solid
Ice has open lattice
H2O has a relatively high boiling point
Hydrogen bonds need to be broken

26
Q

Magnesium melting point: 650°C
Chlorine melting point: -101°C
Describe the structure and bonding of these elements and explain the difference in melting points (6)

A

Mg has a giant structure
Mg has metallic bonding
Electrostatic attraction between positive ions and electrons
Cl has a simple covalent lattice
Cl has induced dipole-dipole
Less energy is needed to overcome induced dipole-dipole than metallic bonds

27
Q

Describe the bonding and structure in graphite

Explain why graphite is a good conductor, a soft material and a very high melting point (5)

A
Giant covalent lattice
Arranged in layers
Good conductor - mobile electrons
High melting point - covalent bonds have to be broken
Soft - weak forces between the layers
28
Q

What is meant by a covalent bond? (1)

A

A shared pair of electrons

29
Q

Name the shape of the ammonia molecule and why ammonia has this shape and a bond angle of 107° (3)

A

Pyramidal
There are 3 bonded pairs and 1 lone pair
Lone pairs repel more than bonded pairs

30
Q

Why does ammonium chloride not conduct electricity when solid but does when dissolved in water? (2)

A

Ions cannot move in a solid

Ions can move in solution

31
Q

What is meant by metallic bonding? (2)

A

Electrostatic attraction between the delocalised electrons and the positive ions

32
Q

Why does H2S have a much lower boiling point than H2O? (2)

A

No hydrogen bonding

Weaker intermolecular forces

33
Q

What is meant by hydrogen bonding? (1)

A

Interaction between lone pair of F, N or O and a H in a neighbouring molecule

34
Q

Explain electronegativity (2)

A

Attraction of an atom for electrons in a covalent bond

35
Q

Why do O-H and N-H bonds have dipoles? (1)

A

Oxygen and nitrogen are more electronegative than hydrogen

36
Q

Why does a water molecule have a different shape to a carbon dioxide molecule? (2)

A

Electron pairs repel
Oxygen in water has 2 bonds and 2 lone pairs
Carbon in CO2 has 2 double bonds

37
Q

Why is water a polar molecule, but CO2 is not?

A

CO2 is symmetrical

In CO2, dipoles cancel