2007 年

D, J, R and Y represent four different compounds. D and J react according to the following equation : D + 2 J → R + 2 Y d grams of D react with j grams of J to give r grams of R and y grams of Y. What is the value of y ?

Which of the following pairs of elements would form a covalent compound ?

M is an element in the Periodic Table. M²⁻ ion possesses 45 neutrons and 36 electrons. What is M ?

How many moles of ethane contain y hydrogen atoms ? (L represents the Avogadro’s constant.)

What is the volume of 0.5 M hydrochloric acid required to react with 1.49 g of lithium oxide for complete neutralisation ? (Relative atomic masses : Li = 6.9, O = 16.0)

A mixture containing 25 cm³ of CH₃CH₂CH₂OH, 25 cm³ of CH₃COOH and 1 cm³ of concentrated H₂SO₄ is heated under reflux. After some time, a pleasant smell is detected. Which of the following statements concerning this experiment is correct ?

20 cm³ of calcium chloride solution contains 1.0 × 10⁻² moles of Cl⁻(aq) ions. What is the molarity of the solution ?

Consider the information below :

Which of the following solids is likely to be an ionic compound ?

Chlorine is bubbled into an aqueous solution P for some time. The colour of P gradually changes to brown. P is NOT likely to be

Questions 20 and 21 refer to the following experiment. When carbon and concentrated sulphuric acid are heated together, sulphur dioxide and carbon dioxide are produced. These two gases are then passed through solution X and solution Y as shown below :

Which of the following combinations of solution X and solution Y can be used to show that sulphur dioxide and carbon dioxide are produced ?