Question

1. How many ml of water are needed to dilute 35ml 4M KCl to 3M?
2. What is the molarity of a solution containing 450 ml of solution containing 45 g of
MgCO3?
3. What is the molality of a solution made by adding 6.5g of NaCl to 600g of water?
4. What are the concentrations of aluminum and sulfate in a 5.0 M solution of
aluminum sulfate?

Answer 1

1)

Moles of KCl$= 4×\frac{35}{1000}=0.14moles$

Volume$=\frac{0.14}{3}=0.047l = 47ml$

2)

Moles of $MgCO_3=\frac{45}{84.3139}=0.534moles$

Molarity $=\frac{0.534×1000}{450}=1.187M$

3)

Moles of NaCl$=\frac{6.5}{58.44}=0.111moles$

Molarity = $\frac{0.111×1000}{600}=0.185M$

4)