1.) What is the molarity of a solution made by dissolving 25.6 g of KOH (5601 g/mol) in enough water to make 3.00 L of solution?
2.) 2 Fe + 3 Cl2 ------> 2FeCl3
How many moles of Fe are needed to produce 76.4 g of FeCl3 (162.3 g/mol)?
How many grams of Fe (55.8 g/mol) are needed to react with 123 g or cl2 (71.0 g/mol)?
1) Molarity is concentration of the solution. It is defined as number of moles of (in this case) KOH per 1 L of solution. (C=n/V)
So, to solve your first problem, we must find the number of moles of KOH in 25.6g of KOH. It can be done using the good old n=m/M equation:
n(KOH) = 25.6g/56.1g/mol = 0.45 mol
Now we know that 25.6g of KOH actually contain 0.45 mol of KOH. The volume of solution is 3L and it is easy to ...
This solution provides a step-by-step explanation in 344 words regarding the definition of molarity, how to calculate molarity of a solution and reading and balancing chemical equations.