OCR Exam Study Guide Questions And Answers Verified 100% Correct

OCR Exam Study Guide Questions And Answers Verified 100% Correct 1 The table below shows standard enthalpy changes of formation, ∆fH. Compound NH4NO3(s) H2O(g) CO2(g) ∆fH / kJ mol-1 -366 -242 -394 What is the enthalpy change for the following reaction? 2NH4NO3(s) + C(s) → 2N2 (g) + 4H2O(g) + CO2(g) A -630 kJ mol-1 B -540 kJ mol-1 C +540 kJ mol-1 D +630 kJ mol-1 - ANSWER A 2 Carbon monoxide reacts with steam in the following reaction equation: CO(g) + H2O (g) CO2(g) + H2(g) ∆H = -40 kJ mol-1 Which change will shift the position of equilibrium to the right hand side of the equation? A decrease in pressure B increase in pressure C decrease in temperature D increase in temperature - ANSWER C 13 Which substance contains hydrogen bonding in the liquid state? A CH3(CH2)4CH3 B CH3(CH2)3CHFCH3 C CH3(CH2)3COCH3 D CH3(CH2)3CH(OH)CH3 - ANSWER D 14 Which volume of oxygen gas, at room temperature and pressure, is required for complete combustion of 1.25 × 10−3 mol of propan-1-ol? A 105 cm3 B 120 cm3 C 125 cm3 D 135 cm3 - ANSWER D 15 Three of the following displayed formulae represent the same isomer of C3H4Cl2 but one structure represents a different isomer, X. Which displayed formula represents X? A B C D - ANSWER D 16 Which alcohol will not react with potassium dichromate(VI) in sulfuric acid? A CH3CH2CH(OH)CH2CH3 B CH3CH2CH(CH3)CH2OH C (CH3)2CHCH(CH3)OH D (CH3CH2)2C(CH3)OH - ANSWER D 17 A section of a polymer chain is shown below. Identify the monomer that would give rise to this section of addition polymer. A E-But-2-ene B Z-But-2-ene C Methylpropene D Propene - ANSWER D 18 (a) A student used the apparatus below in an experiment to determine the enthalpy change of combustion of methanol. The student measured 100 cm3 and poured it into the beaker. The student measured a temperature rise of 10.5 °C. The student calculated the amount of energy transferred to the water. Which of the following uses the appropriate number of significant figures and correct standard form to represent the result of the calculation? A 4.389 × 103 J B 4.39 × 103 J C 43.9 × 102 J D 44.0 × 102 J - ANSWER B 18 (b) The student's calculated enthalpy change was less exothermic than the value in data books. Which of the following errors could have contributed to this result? Error 1: After the final temperature was recorded, the student removed the burner from under the beaker. The flame burnt for a further 5 minutes before weighing the spirit burner. Error 2: The student recorded the final temperature 5 minutes after removing the burner. Error 3: The student spilt some water on the bench when pouring the water from the measuring cylinder into the beaker. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 - ANSWER B 19 A student prepares a standard solution and carries out a titration. The standard solution is placed in the burette. Which of the following would result in a titre that is larger than it should be? 1: Water is added to completely fill the volumetric flask, rather than to the graduation line. 2: The conical flask is washed out with water before carrying out each titration. 3: The pipette is washed out with water before carrying out each titration. A 1, 2 and 3 B Only 1 and 2 C Only 2 and 3 D Only 1 - ANSWER D 1 How many electrons are in a 12Mg 24 2+ ion? A 10 B 12 C 14 D 22 Your ANSWER - ANSWER A 2 What is the formula of chromium(III) sulfate? A Cr3SO4 B Cr(SO4)3 C Cr2(SO4)3 D Cr3SO3 Your ANSWER - ANSWER C 3 Which molecule is non-polar? A SF6 B H2S C PF3 D NH3 Your ANSWER - ANSWER A 4 Which row is correct? Highest pH when added to water Most reactive halogen A MgO F2 B MgO I2 C BaO F2 D BaO I2 - ANSWER C 5 Which equation represents a redox reaction? A Mg + 2HCl → MgCl2 + H2 B MgO + 2HCl → H2O + MgCl2 C MgCO3+ 2HCl → CO2 + H2O + MgCl2 D Mg(OH)2 + 2HCl → MgCl2 + 2H2O - ANSWER A 6 This question is about trends in the periodic table. Which trend is correct? A melting point decreases from lithium to carbon B boiling point decreases from fluorine to iodine C first ionisation energy decreases from lithium to caesium D first ionisation energy increases from nitrogen to oxygen - ANSWER C 7 A sample of a compound M contains 1.46 g of carbon, 0.482 g of hydrogen and 1.69 g of nitrogen. What is the empirical formula of M? A CH2N B C4HN4 C CH4N D C2H4N - ANSWER C 8 A student mixes 100 cm3 of 0.200 mol dm-3 NaCl(aq) with 100 cm3 of 0.200 mol dm-3 Na2CO3(aq). What is the total concentration of Na+ ions in the mixture formed? A 0.100 mol dm-3 B 0.200 mol dm-3 C 0.300 mol dm-3 D 0.400 mol dm-3 - ANSWER C 9 Which mass of substance contains the greatest number of atoms? A 3.00 g of ammonia, NH3