Relative Atomic Mass (OCR GCSE Chemistry A, Combined (Gateway Science Suite)): Flashcards

Mass of 1 atom compared to 1/12 mass of C-12 atom

1/12th the mass of a carbon-12 atom

Weighted average of all isotopes of element

Ar: weighted avg; mass number: single isotope only

$\frac{(\text{mass} \times \text{abund}) + ...}{\text{total abund}}$

Chlorine-35 and Chlorine-37

75% Chlorine-35, 25% Chlorine-37

35.5

Different isotopes contribute to weighted average

Periodic table

Mr, moles, empirical formulas, molecular formulas

$\text{Moles} = \frac{\text{Mass}}{\text{Ar or Mr}}$