First, we need to state the chemical equation for the combustion of PH3
[tex]4PH3\text{ + 8O2 }\to\text{ P4O10 }+6H2O[/tex]And the mass of PH3 is 17.0 grams and we need to know the moles.
In the periodic table, the atomic mass of the P (phosphorus) is 31 and the atomic mass of the H (hydrogen) is 1.
So, you sum the mass of P to the mass of H multiplied by 3 and you obtain this:
[tex]\text{mole}cu\text{lar weight of PH3=31}\cdot1+1\cdot3=34\text{ g PH3/mol}[/tex]With this data, we can search the moles of PH3:
