PLEASE PLEASE PLEASE HEL I NEED HELP ON A CHEMISTRY TEST ALSO PLEASE SHOW ALL WORK AND NO LINKS THANKS

18. Calculate the molarity of each solution below. Show ALL work, units and labels.

a) 1.23 g Na2SO4 in 1.00 L of solution

b) 2.34 g CaCl2 in 0.750 L of solution

c) 45.60 g Pb(NO3)2 in 900.0 mL of solution

19. Calculate the mass of solid is needed to prepare the volume and molarity of each solution below. Show ALL work, units and labels.

a) 750. mL of 0.500 M Na2SO4

b) 500. mL of 1.50 M CaCl2

c) 10.00 L of 1.500 M Pb(NO3)2

20. Calculate the number of milliliters of solution that contain the designated number of grams of solute. Show ALL work, units and labels.

a) 2.48 M Na2SO4 containing 31.2 g solute

b) 3.69 M CaCl2 containing 23.1 g solute

c) 0.6543 M Pb(NO3)2 containing 1.098 g solute