Question

I NEED THIS BY TOMMOROW.... TERRIBLY STUCK D: HELP? 4 QUESTIONS BELOW :D X

(1)A nutritional supplement contains 0.405 g of CaCO3. The recommended daily value of calcuim is 1.00g Ca.
Find the mass in grams of calcium in 0.405g CaCO3. What percentage of the daily value of calcium comes from this tablet?

(2) A solution was made by dissolving 8.20g sodium phosphate (Na3PO4) in water and then diluting to achieve a total volume of 100.0 mL. What is the solution's molarity?

(3) The neutralisation reaction between nitric acid and potassium hydroxide is:
HNO3(aq) + KOH(aq) --> KNO3(aq) + H2O(l)
What is the minimum volume of 1.50M HNO3 needed to completely react with 0.125 L of 0.501 M KOH?
Hint: determine moles of KOH --> stoichiometric ratio of HNO3/ KOH from balanced equation --> determine number moles HNO3 --> determine volume HNO3.

(4) Extension
The neutralisation reaction between sulfuric acid and potassium hydroxide is:
H2SO4(aq) +2 KOH(aq) --> K2SO4(aq) + 2H2O(l)
What is the minimum volume of 1.50M H2SO4 needed to completely react with 0.125 L of 0.501 M KOH?
Hint: determine moles of KOH --> stoichiometric ratio of H2SO4/ KOH from balanced equation --> determine number moles H2SO4 --> determine volume H2SO4.

THANK YOU, WOULD LOVE SOME HELP! :D