P- Amount of substance

Question 1

Ar- relative atomic mass

Answer 1

The weighed average mass of an atom of an element, taking into account its naturally occurring isotopes, relative to 1/12 the mass of an atom of carbon-12.

Question 2

Mr- relative molecular mass

Answer 2

The mass of a molecule of an element or
compound relative to 1/12 the mass of an atom of carbon-12. (sum of all of the Ar in a molecule)

Question 3

Avogadro’s constant

Answer 3

The number of atoms in 12g of C-12.

/no. of particles in a mole

Question 4

What does relative formula mass show?

Answer 4

The RATIO of different ions in the compound.

Question 5

Why would the mass of product made be less than the maximum theoretical mass?

Answer 5

1. Reaction did not go to completion (eg. not heated enough)
2. Products may have been lost during separation from reaction mixture- left in reaction vessel (eg. filtration)
3. Unexpected side products may have been formed
4. The reaction may be REVERSIBLE
5. Gas formed- escape

Question 6

Empirical formula

Answer 6

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

Question 7

Molecular formula

Answer 7

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

(only applies to substances that exist as molecules)
> may be several UNITS of empirical formula within

Question 8

What is the assumption made in the ideal gas equation?

Answer 8

Particles don’t interact so there’s
no forces between them.

Question 9

The ideal gas equation

Answer 9

PV=nRT

P- pressure (Pa)
V- volume (m³)
n- no. of moles
R- molar gas constant (given: 8.31JK⁻¹mol⁻¹)
T- temperature (K)

Question 10

Unit conversion-
kPa to Pa

Answer 10

x 1000

Question 11

Unit conversion-
Celcius to Kelvin

Answer 11

+ 273

Question 12

Unit conversion-
dm³ to m³

Answer 12

/ 1000

Question 13

Unit conversion-
cm³ to m³

Answer 13

/ 10⁶

Question 14

Volume of 1 mole of ideal gas at standard temperature (20ᵒC) & pressure (101kPa)

Answer 14

24dm³

Question 15

What is a solution?

Answer 15

Mixture of solute and solvent particles.

Question 16

What is the concentration?

Answer 16

Amount of solute in a given amount of solution. (mol dm⁻³)

Question 17

dm³ & L

Answer 17

mol dm⁻³ = mol/L

Question 18

mL to dm³

Answer 18

/ 1000

Question 19

g dm⁻³ to mol dm⁻³

Answer 19

/ Mr

Question 20

Stoichiometry

Answer 20

Simplest whole no. ratio in which reactants react & products produced in a reaction.

Question 21

Formula of Suplfate ion

Answer 21

SO₄²⁻

Question 22

Formula of Carbonate ion

Answer 22

CO₃²⁻

Question 23

Formula of Nitrate ion

Answer 23

NO₃⁻

Question 24

Formula of Ammonium ion

Answer 24

NH₄⁺

Question 25

Formula of Phosphate ion

Answer 25

PO₄³⁻

Question 26

Give 2 advantages of high atom economy

Answer 26

1. Conserves natural resources 2. Reduces waste

Question 27

Formula for % atom economy

Answer 27

Mr of desired product _________________________ x 100 Mr of all reactants/ all products (∵ x gain/ loss of atoms)

Question 28

Accuracy

Answer 28

How close a result is to the TRUE VALUE

Question 29

Precision

Answer 29

How close results are to EACH OTHER

Question 30

* for uncertainty ranges

Answer 30

1. same amount of decimal places to reading 2. x greater/ smaller than +/- half of the smallest division of the instrument (eg. 0.05mL)

Question 31

Readings (idea)

Answer 31

From SINGLE judgement eg. reading off a balance, thermometer (x for temp change tho!)

Question 32

Measurements (idea)

Answer 32

DIFFERENCE between 2 JUDGEMENTS eg. stopwatch, pipette # burette- technically has 3 judgement points but the 3rd (endpoint) is subjective ∴ counts as 2

Question 33

% uncertainty for readings

Answer 33

Error ____________ x 100 Measurement

Question 34

% uncertainty for measurements

Answer 34

SUM of errors _____________ x 100 Measurement eg. SUM for +/- 0.1 --> 0.2

Question 35

% yield

Answer 35

moles of products/ moles of reactants x100