Question

A scientist dissolves 10.00 g of sodium hydroxide into 275.0 mL of water. What is the molarity of the solution?

Answer 1

Explanation:

Question

A scientist dissolves 10.00 g of sodium hydroxide into 275.0 mL of water. What is the molarity of the solution?

Solution

Mass of sodium hydroxide (NaOH) taken = 10g

Volume of water = 275 mL = 275/1000 L

Molarity = ?

$molarity \: = \: \frac{weight \: of \: solute(g)}{gram \: molecular \: weight \: of \: solute} \times \frac{1}{volume \: of \: solution(l)}$

GMW of NaOH = 23 + 16 + 1

= 40 g

$molarity \: = \: \frac{10}{40} \times \frac{1}{ \frac{275}{1000} }$

$molarity \: = \frac{1}{4} \times \frac{1000}{275}$

$molarity = \frac{1000}{1100}$

Molarity = 10/11 = 0.9

Molarity = 0.9M

- So, molarity = 0.9M

Answer 2

Answer:

Molarity = 0.91 M

Step-by-step explanation:

Step 1: Calculate number of moles of solute which is Sodium hydroxide

Number of moles = Given Mass ÷ Gram Molecular mass

➝ Number of moles = 10 ÷ 40

➝ Number of moles = 0.25 moles

Step 2: Convert the volume of solution which is given in millilitres to litres.

1000 mL = 1 L

275 mL = 275 ÷ 1000 Litres = 0.275 L

Step 3: Applying molarity formula

Molarity = Number of moles of solute ÷ Volume of solution

⇒ Molarity = 0.25 ÷ 0.275

⇒ Molarity = 0.91 M

∴ Molarity of solution = 0.91 M