Question

What is the molarity of a solution that contains 14.92 grams magnesium oxide (MgO) in 365ml of solution?

a. 1.01 molar solution
b. 1.52 molar solution
c. 11.2 molar solution
d. 87.2 molar solution

Answer 1

Option A. 1.01 molar solution

Step-by-step explanation:

Step 1:

Data obtained from the question. This include the following:

Mass of MgO = 14.92g

Volume of solution = 365mL

Molarity of solution =.?

Step 2:

Determination of the number of mole present in 14.92g of MgO.

This is illustrated below:

Mass of MgO = 14.92g

Molar mass of MgO = 24.3 + 16 = 40.3g/mol

Number of mole MgO =...?

Mole = Mass /Molar Mass

Number of mole of MgO = 14.92/40.3 = 0.370 mole

Step 3:

Determination of the molarity of the solution.

This can be obtained as follow:

Mole of MgO = 0.370 mole

Volume = 365mL = 365/1000 = 0.365L

Molarity =..?

Molarity = mole /Volume

Molarity = 0.370/0.365

Molarity = 1.01M

Answer 2

a. 1.01 molar solution

Step-by-step explanation:

Now we have to recall the formula;

n= CV

Where

n= number of moles of magnesium oxide

C= concentration of magnesium oxide solution = ???

V= volume of magnesium oxide solution= 365 ml

But;

n= m/M

Where;

m= given mass of magnesium oxide= 14.2 g

M= molar mass of magnesium oxide= 40.3044 g/mol

Substituting values;

14.2g/40.3044 g/mol = C×365/1000

0.3523= 0.365 C

C= 0.3523/0.365

C= 0.965

C= 1.00 molar (approx)