Which of the following masses of concentrated HNO₃ (70% by mass) is required to prepare 250 mL of a 2.0 M HNO₃ solution?

1. 90.0 g Conc. HNO₃
2. 70.0 g Conc. HNO₃
3. 54.0 g Conc. HNO₃
4. 45.0 g Conc. HNO₃

What is the mole fraction of the solute in a 1.00 molal aqueous solution?

What is the concentration of a urea solution if 6.02×10²⁰ molecules of urea are present in 100 mL of the solution?

Which of the following is the molality of a 15% (w/v) H₂SO₄ solution having a density of 1.1 g/cm³?

1. 1.2 mol/kg

2. 1.4 mol/kg

3. 1.8 mol/kg

4. 1.6 mol/kg

Which mode of expressing concentration is independent of temperature?

1. Molality

2. Percent by mass

3. Mole fraction

4. All of the above