Take this Exam: A-Level Chemistry: Amount of Substance | Zestly

Question 1

A student dilutes 10.0 cm3 of 2.00 mol dm-3 HCl to a final volume of 250 cm3. What is the new concentration of the acid?

Accepted Answer

0.080 mol dm-3

Question 2

What is the atom economy for the production of hydrogen gas in the reaction: Zn + 2HCl -> ZnCl2 + H2?

Accepted Answer

1.5%

Question 3

Which of the following are true regarding molecular formulas?

Accepted Answer

The molecular formula is a multiple of the empirical formula.

Question 4

5.00 g of CaCO3 is heated and 1.76 g of CO2 is collected. What is the percentage yield? (Molar masses: CaCO3 = 100.0, CO2 = 44.0). The reaction is CaCO3 -> CaO + CO2.

Answer

80.0%

Answer

44.0%

Answer

50.0%

Answer

88.0%

Question 5

Which of the following statements correctly apply to the ideal gas equation $pV = nRT$?

Answer

It assumes gas particles have negligible volume.

Answer

It is most accurate at high pressures and low temperatures.

Answer

It assumes there are no intermolecular forces between gas particles.

Answer

It is only valid for noble gases.