Moles 1

What is the law of conservation of mass

Mass is neither created nor destroyed in a chemical reaction

Who proposed conservation of mass

Antoine Lavoisier

What does conservation of mass mean

Total mass of reactants equals total mass of products

What type of system is required for conservation of mass

Closed system

What is the law of constant proportion

A compound always contains elements in fixed mass ratio

Who proposed law of constant proportion

Joseph Proust

What is Dalton’s atomic theory

Theory that matter is made of atoms combining in fixed ratios

What is relative atomic mass RAM

Average mass of atoms compared to 1/12 of carbon-12

What is relative molecular mass RMM

Sum of atomic masses in a molecule

What is formula mass

Sum of atomic masses in a compound

What is a mole

Amount of substance containing Avogadro’s number of particles

What is Avogadro’s number

6.022 x 10^23

What is Avogadro constant

Number of particles in one mole

What does one mole contain

6.022 x 10^23 particles

What types of particles can a mole represent

Atoms molecules ions

What is molar mass

Mass of one mole in g/mol

What is relationship between mole and mass

Mole equals RAM or RMM in grams

Example NaCl molar mass

58.5 g/mol

What is the unit of moles

mol

What is analogy for mole

A dozen equals 12 a mole equals 6.022x10^23

How many particles in 2 moles

2 x 6.022 x 10^23

How many particles in 0.5 moles

0.5 x 6.022 x 10^23

Why mole concept important

Links mass to number of particles

What is particle

number of atoms molecules or ions

What is chemical amount measured in

moles

What is the formula for moles

moles = mass ÷ molar mass

What is the formula for mass

mass = moles × molar mass

What is the formula for molar mass

molar mass = mass ÷ moles

What is the formula for particles

particles = moles × Avogadro constant

What is the formula for moles from particles

moles = particles ÷ Avogadro constant

What is Avogadro constant value

6.022 x 10^23

What unit is molar mass

g/mol

What is atomic mass of carbon

12

What is atomic mass of hydrogen

1

What is atomic mass of oxygen

16

What is atomic mass of sodium

23

What is atomic mass of chlorine

35.5

What is molecular mass of H2O

18

What is molecular mass of CO2

44

What is molecular mass of NaOH

40

What is molecular mass of HCl

36.5

How to calculate moles from mass

Divide mass by molar mass

How to calculate mass from moles

Multiply moles by molar mass

How to calculate particles from moles

Multiply by 6.022 x 10^23

How to calculate moles from particles

Divide by 6.022 x 10^23

Example moles of C from 120g

10 moles

Example mass of Na from 250 mol

5750 g

Example moles of NaOH from 25g

0.625 mol

Example mass of HCl from 0.004 mol

0.146 g

How to calculate number of atoms in element

Use moles × Avogadro constant

Example atoms in 9g C

4.51 x 10^23

How to calculate molecules in compound

Use moles × Avogadro constant

Example molecules in 2.8g H2O

9.37 x 10^22

Why divide by molar mass

To convert grams to moles

Why multiply by molar mass

To convert moles to grams

What must always be known to calculate moles

Molar mass

What must always be known to calculate particles

Moles

What is key step in mole problems

Convert to moles first

Why mole is central unit

Links mass particles and volume

What is step 1 in calculations

Find molar mass

What is step 2

Convert given value to moles

What is step 3

Convert to required unit

What is common mistake in mole calculations

Forgetting units

What is another mistake

Using wrong molar mass

What must be checked in answers

Units and significant figures