The units for molarity is moles of solute per liter of solution which means if you multiply the molarity of a solution by its volume you get how many moles of solute are in the solution. (0.75Mx0.5L=0.375mol NaCl)
Then you can multiply the moles of sodium chloride (0.375 mol) by its molar mass (58.45 g/mol) to get 21.92g of sodium chloride. That means there is 21.92 grams of sodium chloride in 500mL of 0.75M solution. I hope this helps. Let me know if anything is unclear.
5.00 x 1011/s = 5.05500kilohertz
Mass of CO₂ evolved : 0.108 g
<h3>Further explanation</h3>
Given
1.205g sample, 36% MgCO3 and 44% K2CO3
Required
mass of CO2
Solution
0.36 x 1.205 g=0.4338 g
mass C in MgCO₃(MW MgCO₃=84 g/mol, Ar C = 12/gmol)
= (12/84) x 0.4338
= 0.062 g
0.44 x 1.205 g = 0.5302 g
Mass C in K₂CO₃(MW=138 g/mol) :
= (12/138) x 0.5302
= 0.046 g
Total mass Of CO₂ :
= 0.062 + 0.046
= 0.108 g
I'm not sure if this is what you're looking for, but I suppose you would have to have the solute and the solution to balance the reaction.