91Ó°ÊÓ

We need to find that number of moles in$25.0$g of$He$.

Here we will use the formula of number of moles ,

We are given with gram molecular mass and we know molar mass of substance , so we get;

Number of moles=gram molecular weight/molar mass .

Therefore, number of moles is$\frac{25\cancel{g}}{4\cancel{g}/moles}=6.25$moles

We need to find that number of moles in$25.0$gof$O$

Here we will use the formula of number of moles ,

We are given with gram molecular mass and we know molar mass of substance , so we get;

Number of moles=gram molecular weight/molar mass

Therefore, number of moles$\frac{25\cancel{g}}{16\cancel{g}/moles}=1.56$moles

We need to find that number of moles in$25.0$gof$Al{\left(OH\right)}_3$

Here we will use the formula of number of moles ,

We are given with gram molecular mass and we know molar mass of substance , so we get;

Number of moles=gram molecular weight/molar mass

Therefore,number of moles$\frac{25\cancel{g}}{78\cancel{g}/moles}=0.32$moles

We need to find that number of moles in$25.0$gof$G{a}_2{S}_3$

Here we will use the formula of number of moles ,

We are given with gram molecular mass and we know molar mass of substance , so we get;

Number of moles=gram molecular weight/molar mass

Therefore,number of moles$\frac{25\cancel{g}}{235.6\cancel{g}/moles}=0.106$moles

We need to find that number of moles in$25.0$g of$C_4{H}_{10}$.

Here we will use the formula of number of moles ,

We are given with gram molecular mass and we know molar mass of substance , so we get;

Number of moles=gram molecular weight/molar mass

Therefore,number of moles$\frac{25\cancel{g}}{73.14\cancel{g}/moles}=0.34$moles