A. You are assisting in the lab. You have been given 1 L of a 4 M solution of NaCl, and been asked to dilute it in order to obtain a concentration of 1 M. How much water do you need to add to the starting solution in order to do this?

B. A mixture of sodium has been chemically analysed and it has been found to contain two isotopes 23Na, 30Na, with mass numbers of 23, and 30 respectively. The mixture contains the following proportions of each: 0.86, and 0.14 respectively. What is the relative atomic mass of the mixture?

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