Quantitative Chemistry – TEST 2

 

1.       Which is a correct definition of the term empirical formula?

A.      formula showing the numbers of atoms present in a compound

B.      formula showing the numbers of elements present in a compound

C.      formula showing the actual numbers of atoms of each element in a compound

D.      formula showing the simplest ratio of numbers of atoms of each element in a compound

ANSWER

(Total 1 mark)

 

 

2.       What amount (in moles) is present in 2.0 g of sodium hydroxide, NaOH?

A.      0.050

B.      0.10

C.      20

D.      80

ANSWER

(Total 1 mark)

 

 

3.       How many oxygen atoms are present in 0.0500 mol carbon dioxide?

A.      3.01×10²²

B.      6.02×10²²

C.      6.02×10²³

D.      1.20×10²⁴

ANSWER

(Total 1 mark)

 

 

4.       What is the coefficient for O₂(g) when the equation below is balanced?

__C₃H₈(g) + __O₂(g) → __CO₂(g) + __H₂O(g)

A.      2

B.      3

C.      5

D.      7

ANSWER

(Total 1 mark)

 

 

5.       The temperature in Kelvin of 2.0 dm³ of an ideal gas is doubled and its pressure is increased by a factor of four. What is the final volume of the gas?

A.      1.0 dm³

B.      2.0 dm³

C.      3.0 dm³

D.      4.0 dm³

ANSWER

(Total 1 mark)

 

 

6.       Which of the following compounds has/have the empirical formula CH₂O?

I.       CH₃COOH

II.      C₆H₁₂O₆

III.         C₁₂H₂₂O₁₁

A.      II only

B.      III only

C.      I and II only

D.      II and III only

ANSWER

(Total 1 mark)

 

 

7.       An organic compound A contains 62.0% by mass of carbon, 24.1% by mass of nitrogen, the remainder being hydrogen.

(i)      Determine the percentage by mass of hydrogen and the empirical formula of A.

ANSWER

(3)

 

(ii)      Define the term relative molecular mass.

ANSWER

(2)

 

(iii)     The relative molecular mass of A is 116. Determine the molecular formula of A.

ANSWER

(1)

(Total 6 marks)

 

 

8.       A solution containing ammonia requires 25.0 cm³ of 0.100 mol dm^–3 hydrochloric acid to reach the equivalence point of a titration.

(i)      Write an equation for the reaction of ammonia with hydrochloric acid

(1)

(ii)      Calculate the amount (in mol) of hydrochloric acid and ammonia that react.

(2)

(iii)     Calculate the mass of ammonia in the solution.

(2)

ANSWER

(Total 5 marks)

 

 

9.       Propane and oxygen react according to the following equation.

                        C₃H₈(g) + 5O₂(g) → 3CO₂(g) + 4H₂O(g)

Calculate the volume of carbon dioxide and water vapour produced and the volume of oxygen remaining, when 20.0 dm³ of propane reacts with 120.0 dm³ of oxygen. All gas volumes are measured at the same temperature and pressure.

ANSWER

(Total 3 marks)

 

 

10.     Sodium reacts with water as follows.

2Na(s) + 2H₂O(l) → 2NaOH(aq) + H₂(g)

          1.15 g of sodium is allowed to react completely with water. The resulting solution is diluted to 250 cm³. Calculate the concentration, in mol dm^–3, of the resulting sodium hydroxide solution.

ANSWER

(Total 3 marks)

 

 

11.     100 cm³ of ethene, C₂H₄, is burned in 400 cm³ of oxygen, producing carbon dioxide and some liquid water. Some oxygen remains unreacted.

(a)     Write the equation for the complete combustion of ethene.

ANSWER

(2)

 

(b)     Calculate the volume of carbon dioxide produced and the volume of oxygen remaining.

ANSWER

(2)

(Total 4 marks)