Question

Question #42234

Answer 1

29.8ml

Explanation:

Density of liquid oxygen = 1.141g/`cm^3`
Density of liquid hydrogen = 0.071 g/`cm^3`

Since 1ml=1`cm^3` and `density = (mass)/(volume)` we can calculate the masses of the above:
Mass oxygen`=1.141times10=11.41g`
Mass hydrogen= `0.071 times 50=3.55g`

We can calculate relative molecualr masses (I have used 1d.p. but you may wish to be more accurate)
`Mr (O_2)=16.0 times2=32.0`
`Mr (H_2)=1.0times2=2.0`

We can now work out the number of moles of each:
Moles `(O_2)=11.41/32.0=0.357 mol`

Moles `(H_2)=3.55/2.0=1.775 mol`

The reaction is
`2H_2 +O_2 to 2H_2O`

so 2 moles `H_2` reacts with 1 mole `O_2`
hence unreacted `H_2` = `1.775-(0.357times2)=1.061mol`

And so Mass = `1.061 times 2= 2.122g`

and volume = `2.122/0.071=29.9ml`