Problem 7E

The morality of a solute in solution is defined to be the number of moles of solute per liter of solution (1 mole = 6.02 × 10 23 molecules). If X is the morality of a solution of magnesium chloride (MgCl2), and Y is the morality of a solution of ferric chloride (FeCl3), the morality of chloride ion (Cl- ) in a solution made of equal parts of the solutions of MgCl2 and FeCl3 is given by M = X + 1.5Y. Assume that X has mean 0.125 and standard deviation 0.05, and that Y has mean 0.350 and standard deviation 0.10.

a. Find μM

b. Assuming X and Y to be independent, find σM.

Solution:

Step 1 of 3:

The morality of a solute in solution is defined to be the number of moles of solute per litre of solution. Let X be the mortality of a solution of MgC.and Y is the morality of a solution of FeC. The morality of chloride in a solution made of equal parts of solutions of MgCand FeC is M= X+ 1.5Y. Here X has mean 0.125 and standard deviation 0.05, and Y has mean

0.350 and standard deviation 0.10.

We have to find

- E(X)
- when X and Y are independent.