You have 10.0 ml of a 5.0% NaCl solution. To this you add 5.00ml of a 2.0% NaCl solution. What is the molarity of NaCl in this final mixture?

Answer 1

Na = .05*10 + .02*5 = .6
percent NaCl = .6/15 *100 = 4% =.04

.04/15ml = 40/15 grams/liter

so what is 40 grams of NaCl in mols?

40g/58.44 g/mol = .684 M

Answer 2

label 5 tubes 1-5. Ad 1.50 ml of diluent to each tube. to the first tube, add 500 ul of 1.00 M glucose and mix. transfer 500 ul from the first tube to the second tube and mix. similarly, continue to transfer 500l from each of the remaining tubes to the tube that follows it until all five tubes have been used. what is the final concentration of glucose in tube 5.