take 1 ml, add 9 ml water.
The wording is important here. If it is a 2 *in* 5 dilution, then the scientist would need 200 ml of concentrate. The best way would be to take a graduated cylinder, put about 200 ml of solvent into the cylinder. Then put in the 200 ml of concentrate. Then add enough additional solvent to make a total of 500 ml. Mix, then pour it into a labeled and dated bottle, and screw on the lid. If it is a 2 *to* 5 dilution, then you need 2/7ths concentrate, and 5/7ths solvent. One seventh of 500 ml is about 71.43, so you would need 142.86 ml of concentrate, and fill the rest with solvent until the total is 500 ml.
Add 2 mL of culture to 20 mL of buffer. 2/20 = 1/10
250 ml
25
33,4ml
take 1 ml, add 9 ml water.
To make a 500 dilution, add 1 part of the substance you are diluting to 499 parts of water. For example, if you have 1 mL of the substance, you would add 499 mL of water to make a total volume of 500 mL for the dilution.
1 in 25. (10/250)
32
measure 1 ml of the original solution and add 6.6 ml of distilled water.
The dilution factor is 1:15. This is calculated as the total volume (7.5 ml) divided by the volume of the sample (0.5 ml).
To make a 50% acetone control, you can mix equal parts of acetone and water. For example, if you start with 10 ml of acetone, you would add 10 ml of water to make a 50% acetone solution.
The final volume of the solution will be 68.18 mL. This can be calculated using the formula for dilution, which is M1V1 = M2V2. Solving for V2 (final volume) gives V2 = (M1V1) / M2 = (8.25 M * 25 mL) / 2.40 M = 68.18 mL.
The dilution factor is 1:100, as you're adding 4.95 ml to the original 0.05 ml. The final concentration is calculated by multiplying the original concentration by the dilution factor, resulting in a final concentration of 3.6x10^4 CFU/ml.
100
The wording is important here. If it is a 2 *in* 5 dilution, then the scientist would need 200 ml of concentrate. The best way would be to take a graduated cylinder, put about 200 ml of solvent into the cylinder. Then put in the 200 ml of concentrate. Then add enough additional solvent to make a total of 500 ml. Mix, then pour it into a labeled and dated bottle, and screw on the lid. If it is a 2 *to* 5 dilution, then you need 2/7ths concentrate, and 5/7ths solvent. One seventh of 500 ml is about 71.43, so you would need 142.86 ml of concentrate, and fill the rest with solvent until the total is 500 ml.