JAMB - Chemistry (2005 - No. 19)
25cm\(^3\) of a mixture of noble gases was obtained from air after the removal of other constituents. What was the original volume of air?
2,500 cm3
1250 cm3
125 cm3
80 cm3
Explication
Noble gases, primarily argon, make up about 1% of Earth's atmosphere, with argon being the most abundant at 0.934%.
Volume of noble gases in air mixture = % composition of noble gas X Total volume of air mixture
25cm\(^3\) = 1% X V\(_T\)
25cm\(^3\) = \(\frac{1}{100}\times {V_T}\)
25cm\(^3\) = \(\frac{V_T}{100}\)
V\(_T\) = 25 X 100
∴ V\(_T\) = 2,500cm\(^3\)