10mL of hydrogen combine with 5 mL of oxygen to yield water. When 200 mL of hydrogen at NTP are passed over heated CuO, the CuO loses 0.144 g of its mass. Do these resutls correspond to the law of constant proportions?

Explanation

1st case:
Mass of 10mL hydrogen at NTP `=(2)/(22400)xx10=0.00089g`
Mass of 5 mL of oxygen at NTP=`(32)/(22400)xx5=0.00714g`
Ratio of masses of hydrogen and oxygen
`=0.00089:0.00714=1:8`
2nd Case:
Mass of 200mL of hydrogen at NTP `=(2)/(22400)xx200=0.0178g`
Mass of oxygen lost by CuO which actually combined with 0.0178g hydrogen at NTP to form water =0.144 g
Ratio of masses of hydrogen and oxygen =0.00178:0.144
1=1:8`