Question

Q1) Calculate the mass of nitrogen dissolved at room temperature in an 77.0 L home aquarium. Assume a total pressure of 1.0 atm and a mole fraction for nitrogen of 0.78.

Express your answer using two significant figures

Q2) Magnesium citrate, Mg3(C6H5O7)2, belongs to a class of laxatives called hyperosmotics, which are used for rapid emptying of the bowel. When a concentrated solution of magnesium citrate is consumed, it passes through the intestines, drawing water and promoting diarrhea, usually within 6 hours.

Calculate the osmotic pressure of a magnesium citrate laxative solution containing 29.5 g of magnesium citrate in 254 mL of solution at 37 ∘C (approximate body temperature). Assume complete dissociation of the ionic compound.

Q3)An aqueous NaCl solution is made using 120 g of NaCl diluted to a total solution volume of 1.15 L .

a)

Calculate the molarity of the solution.

Express your answer using three significant figures.

B)

Calculate the molality of the solution. (Assume a density of 1.08 g/mL for the solution.)

Express your answer using two significant figures.

C)

Calculate the mass percent of the solution. (Assume a density of 1.08 g/mL for the solution.)

Express your answer using three significant figures.

Q4)

To what volume should you dilute 56.5 mL of a 4.45 M KI solution so that 23.5 mL of the diluted solution contains 3.20 g of KI?

Q5)

Lead is a toxic metal that affects the central nervous system. A Pb-contaminated water sample contains 0.0013 % Pb by mass.

How much of the water (in mL) contains 145 mg of Pb? (Assume a density of 1.0 g/mL.)

Express your answer using two significant figures.