Given :
15 g of potassium react with water .
To Find :
How much potassium hydroxide and hydrogen gas will be produced by the chemical reaction .
Solution :
Balanced chemical equation is given by :
[tex]2K+2H_2O->2KOH+H_2[/tex]
Number of moles of potassium are :
[tex]n_p=\dfrac{15}{39}\ mole\\\\n_p=0.38\ mole[/tex]
From the chemical equation we can see that 1 mole of potassium produce 2 moles of KOH and 1 mole [tex]H_2[/tex] .
So , 0.38 mole of potassium will produce :
[tex]n_{KOH}=2\times 0.38\\\\n_{KOH}=0.76\ moles[/tex]
[tex]n_{H_2}=0.38\ mole[/tex]
Mass of KOH produced , [tex]0.76\times 56\ g=42.56\ g[/tex] .
Mass of [tex]H_2[/tex] produced , [tex]0.38\times 2=0.76\ g[/tex] .
Therefore , mass of potassium hydroxide and hydrogen gas produced is 42.56 g and 0.76 g respectively .
