The mole, Avogadro's constant and molar mass
Practice Flashcards
Flip to reveal answersWhat is a mole?
Track your progress — Sign up free to save your progress and get smart review reminders based on spaced repetition.
All 10 Flashcards — The mole, Avogadro's constant and molar mass
Sign up free to track progress and get spaced-repetition review schedules.
Question
What is a mole?
Answer
The amount of substance containing **6.02 × 10²³** particles (Avogadro's constant, N_{A}).
Question
What is Avogadro's constant?
Answer
N_{A} = **6.02 × 10²³ mol⁻¹** — the number of particles in one mole.
Question
What is molar mass, M?
Answer
The mass of **one mole** of a substance, in **g mol⁻¹**; numerically equal to the relative atomic/formula mass.
Question
Formula linking amount and mass?
Answer
$n = \dfrac{m}{M}$ — amount (mol) = mass (g) ÷ molar mass (g mol⁻¹).
Question
Formula linking amount and number of particles?
Answer
$N = n\,N_{A}$ — number of particles = amount (mol) × Avogadro's constant.
Question
How do you get mass from amount?
Answer
Rearrange to $m = nM$ — multiply the amount (mol) by the molar mass.
Question
How do you find molar mass from a sample?
Answer
$M = \dfrac{m}{n}$ — divide the mass by the amount in moles.
Question
Atoms of oxygen in 1 mol of CO_{2}?
Answer
2 mol of O atoms = **1.20 × 10²⁴** atoms (each CO_{2} has 2 oxygens).
Question
Units of molar mass?
Answer
**g mol⁻¹** (grams per mole).
Question
Common mole-calculation trap?
Answer
Forgetting to scale by the **number of that atom or ion in the formula** (e.g. 2 Cl⁻ per MgCl_{2}).
Read the notes
Full study notes for The mole, Avogadro's constant and molar mass
Topic 1.4 hub
Counting particles by mass: the mole
More from Topic 1.4
All flashcards in this topic
Chemistry exam skills
Paper structures & tips
Track your progress with spaced repetition
Sign up free — Aimnova tells you exactly which cards to review and when, so you remember everything before your IB exam.
Start Free