Chapter 2

Question 1

Define relative isotopic mass

Answer 1

The average mass of an atom of an isotope of an element relative to 1/12th the mass of a Carbon 12 atom.

Question 2

Define relative atomic mass

Answer 2

The weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of Carbon 12 ( related to percentage abundance and mass of each isotope )

Question 3

What are mass spectrometers and how do they work ?

Answer 3

Ionisation : gaseous sample injected and stream of electrons fired to hit ions and create ions with + charge ( electron is lost )
Acceleration : entire sample enters then electromagnet used to accelerate ions to have same kinetic energy, pushing them through
Drift region : ion detector only recognises ions. Ek= 0/5 x m x (v) squared. Velocity is inversely proportional to mass of ion. Sample is separated due to different masses. Heavier ion = large mass = lower velocity = travel slower = slower to reach detector

Question 4

Define isotope

Answer 4

Atoms of the same element that have the same number of protons and electrons but a different number of neutrons.

Question 5

What is the atomic number of an element ?

Answer 5

Number of protons / electrons in the nucleus

Question 6

What is the mass number of an element ?

Answer 6

The sum of protons and neutrons in the nucleus

Question 7

What is the role of a mass spectroscoper ?

Answer 7

It determines the % abundance of the isotopes in an element.

Question 8

What compound is produced when it is a metal + non metal ?

Answer 8

Ionic

Question 9

What compound is produced when it is a non metal + non metal ?

Answer 9

Covalent

Question 10

Charge on Ammonium ion (NH4)

Answer 10

1+

Question 11

Charge on Hydroxide ion (OH)

Answer 11

1-

Question 12

Charge on nitrate ion (N03)

Answer 12

1-

Question 13

Charge on nitrite ion (NO2)

Answer 13

1-

Question 14

Charge on cyanide ion (CN)

Answer 14

1-

Question 15

Charge on Hydrogencarbonate ion (HCO3)

Answer 15

1-

Question 16

Charge on Hydrogen sulfate ion (HSO4)

Answer 16

1-

Question 17

Charge on Manganate(VII) ion (MnO4)

Answer 17

1-

Question 18

Charge on Carbonate ion (CO3)

Answer 18

2-

Question 19

Charge on Sulfate ion (SO4)

Answer 19

2-

Question 20

Charge on Sulfite ion (SO3)

Answer 20

2-

Question 21

Charge on Sulphide ion ( S )

Answer 21

2-

Question 22

Charge on Dichromate ion (Cr2O7)

Answer 22

2-

Question 23

Charge on Thiosulfate ion (S2O3)

Answer 23

2-

Question 24

Charge on Phosphate ion ( PO4)

Answer 24

3-

Question 25

Charge on Hydride ion (H)

Answer 25

1-

Question 26

Charge on Zinc ion (Zn)

Answer 26

2+

Question 27

Charge on Silver ion (Ag)

Answer 27

1+

Question 28

Charge on Nitride ion ( N )

Answer 28

3-

Question 29

Charge on Phosphide ion ( P )

Answer 29

3-

Question 30

3 steps to write out formulae of ionic compounds

Answer 30

Work out the formula and charges of the separate ions.
Work out how many of each ion is needed to get overall charge of zero.
Put bracket around any polyatomic ion present more than once in the formula.

Question 31

Formula of covalent compounds for single, two, three and four atoms

Answer 31

Mono, di, tri, tetra

Question 32

Most elements are shown as their chemical symbol in equations. What is the exception ?

Answer 32

Elements that exist as small molecules.
Diatomic molecules = H, N, O, F, Cl, Br, I ( exist as 2 )
Phosphorus = P4
Sulfur = S8 but written as S in equations

Question 33

What elements exist in the (g) state ?

Answer 33

H2, N2, O2, F2, Cl2 and noble gases

Question 34

What elements exist in the (l) state ?

Answer 34

Br2 and Hg ( Mercury )

Question 35

What elements exist in the (s) state ?

Answer 35

Everything apart from :
H2, N2, O2, F2, Cl2 and noble gases
Br2 and Hg ( Mercury )

Question 36

State symbol for ionic compounds

Answer 36

Solids ( if water present most will dissolve aqueous ( but not all ) )

Question 37

State symbol for covalent compounds

Answer 37

Water = liquid
Ammonia = gas
Carbon dioxide = Gas

Question 38

How to write a chemical equation

Answer 38

Balance symbol equation.
Write correct formulae of chemicals present.
Include state symbols if asked to.
Ensure there is same type and number of atoms on both sides of equation so that final equation is balanced.