Chemistry Solution Concentration Questions

Question

7.11 g of NaOH (s) was dissolved to make 8.33 L solution to clean the toilet. Calculate the concentration of the solution.

 

What mass of sodium bicarbonate (NaHC03(s)) is required to make 3.75 L of 0.075 mol/L solution?

Answer 1

Gram Molecular Weight of Na = 23

                                    O = 16

                                    H = 1

                                    C = 12

 

Therefore, Gram Molecular Weight of NaOH =  23+16+1 = 40

 

7.11 g / 40 g = 0.17775 moles of NaOH

 

0.17775 m / 8.33 L = 0.02134 moles / liter

 

Concentration of solution is 0.02134 M

 

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In order to make 3.75 L of 0.075 mol/L solution, you need 3.75 * 0.075 or 0.28125 moles

 

Gram molecular weight of NaHCO₃ = 23+1+12+16*3 = 84

 

0.28125 moles of NaHCO₃ is 0.28125 * 84 = 23.625 grams