CHM256 QUIZ 1 (Friday 22 March 2019)

Define the term quantitative analysis.

• Determination of molecular weight of a given sample

• Determinationof compositions/components/analytes present in a given sample

• Determination of amount of compositions /components/analytes present in a given sample

• Determination of chemical formula of a given sample

What is the molality of a solution in which 3.0 moles of NaCl is dissolved in 1.5 Kg of water?

• 2.0 M

• 0.22 m

• 135 m

• 2.0m

How do you calculate the molarity of a solution?

• By tasting it.
• Dividing the moles of solute by the L of  solution
• Dividing the moles of solute by the kg of  solvent
• By adding the sum of the molecular weight of the elements in the substance.

A 3 M solution has how many moles per liter?

• 1
• 2.5
• 4
• 3

A 2400.-gram sample of an aqueous solution contains 0.012 gram of NH₃. What is the concentration of NH₃ in the solution, expressed as parts per million?

• 5.0 ppm

• 15 ppm

• 20. ppm

• 50. ppm

What is the concentration of a solution, in parts

per million, if 0.02 gram of Na₃PO₄ is dissolved in 1000 grams of water?

• 20 ppm

• 2 ppm

• 0.2 ppm

• 0.02 ppm

An aqueous solution contains 300. parts per million of KOH. Determine the number of grams of KOH present in 1000. grams of this solution.

• 0.3 g

• 3.0 g

• .000003 g

• 300 g

What is the volume of solution needed to make a 3.5% by volume solution using 2.0mL of solvent?

• 57 mL
• 0.57 mL
• 7 mL

Both of these solutions have a volume of 30 mL. Which solution is more concentrated?

• orange solution

• green solution

• they are equally concentrated

Calculate the mass of solid sodium sulfate (Na₂SO₄) for the preparation of 250 mL solution of 25 ppm Na⁺.

• 0.0152 g

• 0.0193 g

• 0.1520 g

• 0.0199 g