Amount of Substance

Question 1

Nitrate ion

Answer 1

NO3-

Question 2

Sulfate ion

Answer 2

SO42-

Question 3

Carbonate ion

Answer 3

CO32-

Question 4

Hydrogencarbonate ion

Answer 4

HCO3-

Question 5

Phosphate ion

Answer 5

PO43-

Question 6

Nitric acid

Answer 6

HNO3

Question 7

Sulfuric acid

Answer 7

H2SO4

Question 8

Ethanoic acid

Answer 8

CH3COOH

Question 9

Kinetic theory of gases

Answer 9

Most volume is occupies by empty space, particles are far apart.
Constantly moving in random directions, but in straight lines.

Question 10

Standard states

Answer 10

Temperature - 273K
Pressure - 100KPa

Question 11

Ideal Gas Equation

Answer 11

pV = nRT

Question 12

Relative Atomic Mass, Ar

Answer 12

average mass of an atom of an
element
1/12th x the mass of one atom
of carbon-12.

Question 13

Relative Molecular Mass, Mr

Answer 13

average mass of one molecule of
an element or compound
1/12th x the mass of one atom
of carbon-12.

Question 14

Relative Formula Mass, Mf

Answer 14

average mass of one formula
unit of a compound
1/12th x the mass of one atom
of carbon-12.

Question 15

Avogadro’s Constant

Answer 15

6.023x10^23

Question 16

A mole

Answer 16

One mole contains 6.023x10^23 atoms, ions or molecules.
The mass of a mole of atoms in an element is the Ar of the element.

Question 17

Finding the number of atoms/molecules/ions

Answer 17

number of moles x Avogadro’s constant

Question 18

Finding moles of solids

Answer 18

number of moles = mass/Mr

Question 19

Finding moles in solution

Answer 19

number of moles = concentration x volume.

Question 20

Atomic number

Answer 20

The number of protons in the nucleus of its atom - it identifies the element.

Question 21

Mass number

Answer 21

The total number of protons and neutrons in the nucleus.

Question 22

Isotope

Answer 22

Atoms of the same element with different numbers of neutrons.

Question 23

Relative Isotopic Mass

Answer 23

Mass of one isotope
1/12 x the mass of a carbon-12
atom

Question 24

Units (K, m3)

Answer 24

Degrees + 273 = K
cm3 / 1000 = dm3 / 1000 = m3

Question 25

Percentage Yield

Answer 25

Tells us about the practical efficiency of the process.
Yield = the number of moles/grams of a specified product / theoretical maximum number of moles/grams of the product x 100.

Question 26

How can yield be lost?

Answer 26

The practical process of obtaining a product.
Reversible reactions do not go to completion.
Heat loss, incomplete combustion.

Question 27

Atom economy

Answer 27

mass of desired product/total mass of reactants x 100

Question 28

What is atom economy

Answer 28

Found from the balanced equation of a reaction.
Tells us in theory how many atoms will be wasted.

Question 29

Empirical Formula

Answer 29

The simplest whole number ratio of atoms of each element in a compound.

Question 30

Molecular Formula

Answer 30

The actual number of atoms of each element in a compound.

Question 31

Calculating Empirical Formula

Answer 31

1. Divide mass (or % mass) of each element in its compound by its Ar (finding moles).
2. Divide each number by the smallest overall mole value.

Question 32

Empirical Formula with a Hydrated Salt

Answer 32

They have the formula xH2O, where x is the number of water molecules attached to each salt molecule.

Question 33

What are Back Titrations?

Answer 33

A two-stage analytical technique.
1. Reactant A of an unknown [] is reacted with excess Reactant B of known [].
2. A titration is performed to determine the amount of reactant B.
They are used when: one reactant is volatile, an acid or base is insoluble, a reaction is too slow.