Question

1. "After cleaning and filling your buret, you take an initial reading of the volume and determine it to be 0.25 mL. You add some of the solution to a beaker, and take a final reading of the buret at 29.50 mL. What volume of solution did you add to the beaker?"

2.Magenisum carbonate (MgCO3) is a common active ingredient in antacids. Each mole of magnesium carbonate can neutralize two moles of acid. If one tablet neutralized 0.0122 moles of acid, how many milligrams of active ingredient were in the tablet?

Answer 1

1. Initial reading of volume burete = 0.25 mL

final reading of the buret = 29.50 mL

hence, volume of solution added to beaker = final reading-initial reading

= 29.50-0.25

= 28.25 mL

2. given: MgCO₃ active ingredient in antacid.

1 mole of MgCO₃ neutralizes 2 moles of acid.

1 mole  MgCO₃ = 2 moles acid

hence, 0.0122 moles of acid = (0.0122*1)\2

= 0.0061 moles of MgCO₃

hence, 1 tablet of antaci contains 0.0061 moles of MgCO_3.

1 mole of MgCO_3.= 84 g ( i.e molecular weight of MgCO₃)

therefore, 0.0061 moles of MgCO₃ = 0.0061*84 = 0.5124 g  MgCO₃ = 512.4 mg MgCO₃