Question

# 1. How to make 20ml of 3M NaCl? 2. What is the percent concentration of 3M...

1. How to make 20ml of 3M NaCl?

2. What is the percent concentration of 3M NaCl?

3. What is the molar concentration of 10% NaCl?

4. Your stock solution is 5M NaCl and your goal is to make 25ml of 0.5M NaCl (all in water). What volume of stock should you use?

5. Make a reagent solution for enzymatic digestion of plasmid in water.

The reaction conditions require:

2x digestion buffer

0.5% bovine serum albumin

10 mM sodium chloride

You have 20 samples requiring 50ul of this mixture.

You have:

10X stock solution of digestion buffer

A 10% stock solution of albumin

A 1M stock solution of NaCl

Define the volume of water required to obtain the final solution volume.

6. How to make 200ml of Yeast Growth Medium in water?

Yeast Growth Medium:

56 mM glucose

20 mM HEPES

You have dry (powder):

HEPES     MW 238.3

Glucose    MW 180.16

1) MW of NaCl = = 58.44 g/mole.

V = 20ml = 0.02 L.

C = 3M

(V x C x MW) = 0.02 L X 3 M X 58.44 g/mole = 3.506 g NaCl dissolved in 20 ml water.

2) The percent concentration = 3.506 x 100 /(20+3.506) = 14.92%.

3) 10% NaCl solution has 10g of NaCl in 100ml of solution or 100g of NaCl in 1000ml.

Molarity = 100/58.44 = 1.711 moles of NaCl.

Therefore the molar concentration of a 10% NaCl solution is 1.711 M NaCl.

4. C1 = 5M, V1 = ? C2 = 0.5M, V2 = 25ml

We have C1 x V1 = C2 x V2 => V1 = C2 x V2 / C1 = 0.5 x 25 / 5 = 2.5 ml

Volume of stock solution required is 2.5 ml.