There would be 0.175 moles of solute contained in a 500.0 milliliter solution that has a concentration of 0.35 M.
Let x be the number of moles
Since the equation is moles/liters=molarity, change 500 mL to liters:
500.0 mL=0.5L
Divide:
x/0.5L = 0.35M
Cross multiply: x=0.35*0.5
x=0.175 moles
