Question

Calculate the number of moles in each of the following:

a.$82.0$g of $Ag$

b . localid="1653462860909" $0.288$gof $C$

c. localid="1653462869919" $15.0$gof ammonia, $N{H}_3$

d. localid="1653462880276" $7.25$gof $C{H}_4$

e. localid="1653462890852" $245$g of$F{e}_2{O}_3$;

Short answer

The number of moles in each of the following :

a.$0.766$moles

b.$0.024$moles

c.$0.882$moles

d. $0.45$moles

e.$1.53$moles

Step-by-step solution

Part (a) Step 1: Given information

We need to find number of moles in $82$gof $Ag$.

Part (a) Step 2: Explanation

Here, we need to calculate number of moles , we will use the formula for number of moles;

We are given with the gram molecular weight , and we know the molar mass for this element , so we get ;

Number of moles=gram molecular weight/molar mass

So, number of moles=$\frac{82\cancel{g}}{107.8\cancel{g}/moles}=0.766$moles

Part (b) Step 1: Given information

We need to find number of moles of $0.288$gof $C$.

Part (b) Step 2: Explanation

Here, we need to calculate number of moles , we will use the formula for number of moles;

We are given with the gram molecular weight , and we know the molar mass for this element , so we get ;

Number of moles=gram molecular weight/molar mass

number of moles=$\frac{0.288\cancel{g}}{12\cancel{g}/moles}=0.024$moles

Part (c) Step 1: Given information

We need to find number of moles of $15.0$gof ammonia.

Part (c) Step 2: Explanation

Here, we need to calculate number of moles , we will use the formula for number of moles;

We are given with the gram molecular weight , and we know the molar mass for this element , so we get ;

Number of moles=gram molecular weight/molar mass

number of moles =$\frac{15\cancel{g}}{17\cancel{g}/moles}=0.882$moles

Part (d) Step 1: Given information

We need to find number of moles of $7.25$gof $C{H}_4$.

Part (d) Step 2: Explanation

We are given with the gram molecular weight , and we know the molar mass for this element , so we get ;

Here, we need to calculate number of moles , we will use the formula for number of moles

Number of moles=gram molecular weight/molar mass

number of moles =$\frac{7.25\cancel{g}}{16\cancel{g}/moles}=0.45$moles

Part (e) Step 1: Given information

We need to find number of moles of $245$gof $F{e}_2{O}_3$.

Part (e) Step 2: Explanation

We are given with the gram molecular weight , and we know the molar mass for this element , so we get ;

Here, we need to calculate number of moles , we will use the formula for number of moles

Number of moles=gram molecular weight/molar mass

number of moles =$\frac{245\cancel{g}}{159.69\cancel{g}/moles}=1.53$moles