Chemical Calculation For Moles in Chemistry

Which of the following is a unit for concentration of a solution?

• mol dm^-3

• cm³ s^-1

• m s^-1

If 1.5 mol of copper sulfate is dissolved to make a solution with a volume of 2 dm³, what is the concentration of the solution?

• 3 mol dm^-3

• 0.75 mol dm^-3

• 1.33 mol dm^-3

A solution has a volume of 650 cm³. What is the volume of this solution in dm³?

• 0.65 dm³

• 650,000 dm³

• 6.5 dm³

How many moles of hydrochloric acid are present in 25 cm³ of a solution which has a concentration of 0.1 mol dm^-3?

• 2.5 moles

• 0.25 moles

• 0.0025 moles

Which law states that equal volumes of different gases contain the same number of molecules?

• Newton's second law

• Avogadro's law

• The law of conservation of mass

A sample of methane gas has a volume of 120 cm³ at room temperature and pressure. The molar volume is 24 dm³. How many moles of methane are present in the sample?

• 2,880 moles

• 5 moles

• 0.005 moles

What volume of carbon dioxide would be formed by the complete combustion of 20 cm³ of ethene? The equation is:

C₂H₄(g) + 3O₂(g) → 2CO₂(g) + 2H₂O(l)

• 20 cm³

• 40 cm³

• 80 cm³

What volume of carbon dioxide gas will be produced by the complete combustion of 30g of carbon? Equation:

C(s) + O₂(g) → CO₂(g)

The molar volume is 24 dm³.

• 30 dm³

• 60 dm³

• 120 dm³