Q. 7.27 - An Introduction to General, Organic, and Biological Chemistry

Question

Calculate the number of moles in $25.0$g of each of the following: 

a. $He$

b. $O$

c. $Al{\left(OH\right)}_3$

d. $G{a}_2{S}_3$

e. $C_4{H}_{10}$, butane 

Step-by-Step Solution

Answer

The number of moles in $25.0$ g of each of the following :

a. $6.25$ moles

b.   $1.56$ moles       

c.  $0.32$ moles

d.$0.106$ moles

e. $0.34$ moles

Part (a) Step 1: Given information

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

Part (a) Step 2: Explanation

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

Part (b) Step 1: Given information

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

Part (b) Step 2: Explanation

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

Part (c) Step 1: Given information

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

Part (c) Step 2: Explanation

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

Part (d) Step 1: Given information

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

Part (d) Step 2: Explanation

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

Part (e) Step 1: Given information

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

Part (e) Step 2: Explanation

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