AS Chemistry OCR A MCQ

Which statement about the periodic table is not correct?

• The elements are arranged in groups with similar chemical properties.

• The elements are arranged in periods with repeating trends in properties.

• The elements are arranged in order of increasing atomic number.

• The elements in the halogen group increase in reactivity down the group.

Which molecule contains the largest bond angle?

What is the percentage, by mass, of O in Mg(NO₃)₂·4H₂O?

• 29.05%

• 43.58%

• 50.84%

• 72.63%

50 cm³ of 6.0 mol dm^–3 HCl is mixed with 90 cm³ of 3.0 mol dm^–3 HNO₃. What is the H⁺(aq) concentration in the resulting solution?

• 1.9 mol dm^–3

• 2.1 mol dm^–3

• 4.1 mol dm^–3

• 4.5 mol dm^–3

Ethene reacts with hydrogen to form ethane. C₂H₄(g) + H₂(g) → C₂H₆(g)      ΔH = –125 kJ mol^–1 The table below shows some average bond enthalpies. Calculate the bond enthalpy of the bond C-H

• –826.0 kJ mol^–1

• –413.0 kJ mol^–1

• +413.0 kJ mol^–1

• +826.0 kJ mol^–1

Which substance(s) experience(s) induced dipole-dipole interactions (London forces)?          1  C₂H₅OH          2  H₂O          3  SiO₂

• 1, 2 and 3

• Only 1 and 2

• Only 2 and 3

• Only 1

What is the name of the reaction when an element is both oxidised and reduced?

Which atom is not an isotope of iodine?

• A

• B

• C

• D

Which element has atoms with the greatest number of singly occupied orbitals?

• C

• Cl

• Ca

• Ga

The equation for the combustion of C₇H₈ is shown in the following equation. C₇H₈(l) + 9O₂(g) 7CO₂(g) + 4H₂O(l) Enthalpy changes of formation are shown in the table.

Calculate the enthalpy of combustion, in kJ mol^–1, for the hydrocarbon C₇H₈

• –3914

• –692

• +692

• +3914