AP Chemistry / Unit 1: Atomic Structure and Properties
1.1 Moles and Molar Mass
Notes
A mole is $6.022\times10^{23}$ particles (Avogadro's number). Molar mass (g/mol) links grams and moles.
- moles = mass ÷ molar mass; particles = moles × $6.022\times10^{23}$.
Practice
How many moles are in 36 g of water (18 g/mol)?
$36\div18$.
0.5 mol of $\mathrm{CO_2}$ contains how many molecules?
Half of Avogadro's number.
The molar mass of $\mathrm{NaCl}$ (Na 23, Cl 35.5):
$23+35.5$.
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