1 ml. salt is added to 19 ml. of distilled water. What is the percentage of salt in the dilution?
Answers
Step-by-step explanation:
. You need to make a 1:5 dilution of a solution. You need 10 ml of the diluted solution. How much initial sample and diluent should you use?
Answer: 1:5 dilution = 1/5 dilution = 1 part sample and 4 parts diluent in a total of 5 parts. If you need 10 ml, final volume, then you need 1/5 of 10 ml = 2 ml sample. To bring this 2 ml sample up to a total volume of 10 ml, you must add 10 ml - 2 ml = 8 ml diluent.
2. How would you prepare 500 ml of a 10% NaCl solution?
Answer: In this problem, the % solution is the number of grams solute in 100 ml solvent, so a 10% solution of NaCl is 10 grams NaCl in 100 ml water. But you need 500 ml, final volume, so 10 g x 5 = 50 g NaCl.
3. If you have DNA with a concentration of 2 µg/µl, how much DNA (in µl) must be added to make a 20 µl solution with a DNA concentration of 1 µg/µl?
Answer: Since you know the initial concentration (2 µg/µl), the final concentration (1 µg/µl), and the final volume (20 µl), the following formula can be used to calculate the amount of DNA needed (initial volume)