Question

How many grams of H2S needed to be added to create 350 mL of a 0.7 M solution?

Answer 1

Given :

• Volume of solution = 350 mL
• Molarity of solution = 0.7 M

To find :

Mass of H₂S required.

Formula used :

• Molarity = Number of mole of solute ÷ volume of solution in L
• Number of mole = mass ÷ Molar mass

Solution :

First of all we need to find out number of mole of H₂S.

$\sf \implies \: 0.7 = \: \dfrac{Number \: of \: mole \: of \: H_2S}{ \frac{350}{1000} } \: mol$

$\sf \implies \: Number \: of \: mole \: of \: H_2S \: = \: 0.7 \: \times \dfrac{350}{1000} \: mol$

$\sf \implies \: Number \: of \: mole \: of \: H_2S \: = \: \dfrac{245}{1000} mol$

$\sf \implies \: Number \: of \: mole \: of \: H_2S \: = \: 0.245 \: mol$

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Now we will find mass of H₂S required

➝ Mass of H₂S required = Number of mole of H₂S × molar mass

➝ Mass of H₂S required = 0.245 mol × 34g/mol

➝ Mass of H₂S required = 8.33 g

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ANSWER : 8.33 grams