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

a. 1.01 molar solution

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)

Option A. 1.01 molar solution

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 is: c. the experiment shows that the red substance experienced a chemical change.

this is chemical change (chemical reaction), because two new substances are formed (metalig liquid and gas), the atoms are rearranged and the reaction is followed by an energy change.

this is example of chemical decomposition.

chemical decomposition (analysis) is the separation of a single chemical compound into its two or more elemental parts or to simpler compounds.  

chemical decomposition is opposite of chemical synthesis.

- lead + phosphoric acid = hydrogen + lead(ii) phosphate