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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)
measure 1 ml of the original solution and add 6.6 ml of distilled water.
16
32
An 8-fold dilution means you are making your solution 1/8 less concentrated. So, if you want to make 100 ml of a solution diluted 8 fold you would do as follows: 1/8=.125 100*.125= 12.5 Mix 12.5 mL of your concentrated solution with 87.5 mL of your solvent (water etc..) to bring the final volume to 100 mL. If you wanted to perform a ten fold dilution you would simply mix 10 mL of your concentrated solution with 90 mL of your solvent. 1/10=.1 100*.1=10
100
Parallel dilution is the dilution of a solution with equal quantity of the same solvent with which the solution is made. e.g., 1mL of 100µg/ml strength aqueous solution can be diluted to 2mL of 50µg/mL strength solution by adding 1mL 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.
cfu/ml = (no. of colonies x dilution factor) / volume inoculated