PLEASE HELP​

What is the molarity of the solution produced when 145 g of nacl is dissolved in sufficient water to prepare 2.75 l of solution?

Areaction is first order. if the initial reactant concentration is 0.0200 m, and 25.0 days later the concentration is 6.25 x 10-4 m, then its half-life is:

You dissolve 8.65 grams of lead(l) nitrate in water and then you add 2 50 grams of aluminum. this reaction occurs 2ai(s)+ 3pb(no3)2(aq) -3pb(s)+ 2aino3la(aq) the theoretical yield of solid lead?