Week 4 How much mL of pure Hydrochloric acid I need to make 2M solution of final

Question

Week 4 How much mL of pure Hydrochloric acid I need to make 2M solution of final volume 1L? Hint. Consider density of HCl as 1g0 1. 2, How can I make a 100mL of 0.1% glucose solution using "1% glucose solution and Water" If I add 20mL of HCI (pure) and 40mL HBr (pure) in 940mL water, What is the concentration of the following in terms of %(v/v): 3. a. HCI b. HBr If I add, 10 mL of more water- c. What will be the concentration of HCI now? Leave the answer in fraction form. You have a protein solution of 42 mg/mL. How can you make a protein solution (100mL) of concentration 2microgram/mL using: 4. a. The 42mg/mL solution b. Water

Explanation / Answer

1) Density = Mass / Volume

Molarity = mol / L

V1 = 1 L, V2 = ?, M1 = 2M, M2 = ?

Density = 1 g/cm3 = 1 g/ml

1 g/ml = mass / 1L

Mass = 1000 g.

Interms of mol :

Molecular weight of HCl = 36.46 g /mol

(1000 g x 0.377) / 36.46 g/mol = 10.34 mol = 10.34 mol/L = 10.34 M

V1 M1 = V2 M2

1 L x 2 M = V2 x 10.34 M

V2 = 0.19 L = 193 mL

2) 1 % glucose solution and water = 1 g of glucose in 100 mL of water = 1g/100 mL

0.1 % glucose solution = 0.1 g / 100 mL

Molecular weight of glucose = 180 = 180 g/L = 1 M

Therefore, 10 g/ L= 0.055 M

V1 C1 = V2 C2

? x 1 M = 100 mL x 0.055 M

V1 = 5.55 mL

Take 5. 6 mL from "1 % glucose solution and water" and make up to 100 mL with water.

3) % v/v = [(Volume of solute) / (Volume of solution) ] x 100

20 mL HCl + 40 mL HBr = 60 mL + 940 mL water = 1000 mL solution

a. % v/v = (20 mL HCl / 1000 mL solution) x 100 = 2 %

b. % v/v = (40 mL HBr / 1000 mL solution) x 100 = 4 %

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