Amount of substance and the mole - 3.1 - (2) Flashcards Preview

OCR (A) A Level Chemistry - Module 2 - Chapter 3 > Amount of substance and the mole - 3.1 - (2) > Flashcards

Flashcards in Amount of substance and the mole - 3.1 - (2) Deck (8)
1
Q

What does the molar mass, M, give a convenient way for?

A

linking moles with mass for any chemical substance

2
Q

What does the molar mass give?

A

it gives the mass in grams in each mole of the substance

3
Q

What is the molar mass?

A

it is the mass per mole of a substance

4
Q

What are the units of molar mass?

A

g mol^-1

5
Q

By what equation is the amount of substance (n), mass (m), and molar mass (M), linked by?

A

amount (n) = mass (m) / molar mass (M), OR, n = m/M

6
Q

Example 1: Calculate the amount of substance, in moles, in 96.0g of carbon, C

A

n = m / M = 96.0 / 12.0 = 8.0mol

7
Q

Example 2: Calculate the mass, in g, of 0.050 mol of NO2

A

rearrange n = m / M = n x M = 0.050 x 46.0 = 2.3g

8
Q

Example 3: Calculate the molar mass when 2.65g contains 0.025mol of a substance

A

n = m / M —> rearrange: M = m / n = 2.65 / 0.025 = 106.0g mol^-1