Question

What would be the mass of a 33.5dm3 sample of O2 at STP?

Answer 1

Answer:

• One mole of oxygen is equivalent to 16 grams.

→ But at STP, 22.4 dm³ are occupied by 1 mole.

${ \tt{22.4 \: {dm}^{3} \: \dashrightarrow \: 16 \: grams}} \\ { \tt{33.5 \: {dm}^{3} \: \dashrightarrow \: ( \frac{33.5 \times 16}{22.4} ) \: grams}} \\ \\ \dashrightarrow \: { \boxed{ \tt{23.94 \: g \approx \: 24 \: grams}}}$