Question

What mass of H2O is formed when H2 reacts with 384 g of 02?

Answer 1

I got `432 \ "g"`.

Explanation:

We first need to write down the balanced equation for the reaction. That is:

`2H_2(g)+O_2(g)->2H_2O(g)`

So, the mole ratio between `O_2` and `H_2O` is `1:2`, i.e. there are `2` moles of water produced for every mole of oxygen reacted with hydrogen.

In here, `384 \ "g"` of oxygen gas is used. The molar mass of `O_2` is `32 \ "g/mol"`. So, the amount of moles used here is

`(384cancel"g")/(32cancel"g""/mol")=12 \ "mol of" \ O_2`

Since `12` moles of oxygen gas are used, then `12*2=24 \ "mol"` of water is produced.

Water has a molar mass of `18 \ "g/mol"`.

So, `24cancel"mol"*18 \ "g/"cancel"mol"=432 \ "g"` of `H_2O` was produced.