How many moles of oxygen are contained in one litre of air if its volume content is 21 % in standard conditions?

Question

How many moles of oxygen are contained in one litre of air if its volume content is 21 % in standard conditions? (A) 0.21 mol (B) 0.045 mol (C) 0.067 mol (D) 0.0094 mol

Tardigrade Admin · Accepted Answer

Oxygen content in 1 L at STP =(1 × 21/100)=0.21 L 22.4 L at STP =1 mol hence 0.21 L at STP =(1 × 0.21/22.4)=0.009375 mol

Q. How many moles of oxygen are contained in one litre of air if its volume content is $21%$ in standard conditions?

$0.21 m o l$

$0.045 m o l$

$0.067 m o l$

$0.0094 m o l$

Oxygen content in $1 L$ at $STP = \frac{1 \times 21}{100} = 0.21 L$
$22.4 L$ at $STP = 1 m o l$
hence $0.21 L$ at $STP = \frac{1 \times 0.21}{22.4} = 0.009375 m o l$

Q. How many moles of oxygen are contained in one litre of air if its volume content is 21% in standard conditions?

0.21mol

0.045mol

0.067mol

0.0094mol