# Homework Help: Finding mEq/L of Ba

1. Aug 28, 2011

### cmgbruschi

1. The problem statement, all variables and given/known data Barium bromide BaBr2 (875.3 mg) was dissolved in water to make one liter of solution. Express the concentration in the following units: mEq/L of Ba.

2. Relevant equations Ba has a charge of 2+ which means it has 2 Eq in 1 mole.

3. The attempt at a solution First I changed the 875.3 mg into .8753 g of BaBr2. The thing that really confuses me is how do I know how many grams of Ba is in .8753 g of BaBr2? I understand how to do this problem if it asked for the mEq/L of BaBr2, but I'm stuck because I can't figure out how many grams of just Ba is in .8753g of BaBr2. Once I figure out the g of Ba I can convert it into moles since there are 137.3 g per mole of Ba.

2. Aug 29, 2011

### chemisttree

Why couldn't you do the same thing for BaBr2? Equivalents don't 'equate' to charge either.

example

H3PO4 <-------> 3H+ + PO4-3

In this example, there are three equivalents of H+ per mole of H3PO4 and only one equivalent of PO4-3. Notice how the number of equivalents are unrelated to the charge on the ions generated?