Lab Ops & Math - Math Practice

Add 30g NaCl to 70g water

Make a 30% w/w NaCl aqueous solution:

Add 30g NaCl to 70g water (total 100g)

Make 100g of 30% NaCl aqueous solution:

Add H20 to 0.5g NaCl up to 100mL

Prepare 100mL of a 0.5% NaCl solution:

Add 25mL of H2SO4 to 75mL H2O

Prepare a 25% H2SO4 solution:

10.5 mL

How much 95% alcohol is required to make 200 mL of 5% alcohol?

2.5g

Prepare 500mL of 0.5% NaOH (how many grams of NaOH is needed?)

18.75%

A solution contains 45g of solute in 240 mL of solution. What is the % concentration?

58.5g

Make 500mL of 2M NaCl (GMW = 58.5) (How many grams of NaCl needs to be diluted in 500mL?)

0.35M

What is the molarity of a solution in which there are 25g of Na2SO4 in 500mL of solution? GMW = 142

79 mg/dL

Absorbance of the unknown = 0.252

Standard absorbance = 0.640

Standard concentration = 200 mg/dL

Concentration of the unknown = (?)

20%

Express 3/15 as a percentage

0.7%

Express 0.7 as a percentage

200 mL

If there are 5 g of NaCl in 100 mL of solution, how many mL of the same concentration would 10 g of NaCl make?

2

How many grams of substance would be required to make 100 mL of solution if 5 g will make 250 mL?

1:10 serum:saline

If 300 uL of saline is added to 30 uL of serum, what is the dilution ratio of serum to saline?

25,000 uL solution

How much of a 1/50 dilution can be made with 500 uL of urine?

1/135

A 10% solution is to be diluted with water using a series of four dilutions. The dilution in tube 1 is 1/5, followed by a three fold dilution series The dilution in the fourth tube would be?

1:9 serum to saline

If 100 uL of solution serum in saline contains 90 uL of saline, what is the ratio for the solution?

0.675 N

What is the resulting concentration of a solution of 30mL of a 4.5N is diluted up to 200 mL?

14,125 cells/mL^3

A white cell count is done on a blood sample that has been diluted 1 to 25. The number of cells counted in the sample is 565 cells per milliliter cubed. What number should be reported for the undiluted sample?

0.0000625

Change 6.25 x 10^-5 to a decimal:

625,000

Change 6.25 x 10^5 to a decimal

35

Change 3.5 x 10^1 to a decimal

6.53 x 10^8 ng

Convert 653 mg to ng

3 x 10^-1

Convert 300 mL to L

6.5 x 10^4 nm

Convert 0.065 mm to nm