AA240
Topic 3—Geometry and trigonometry, SL 3.5—Unit circle definitions of sin, cos, tan. Exact trig ratios, ambiguous case of sine rule, SL 3.6—Pythagorean identity, double angles, SL 3.7—Circular functions: graphs, composites, transformations, SL 3.8—Solving trig equations
17M.2.HL.TZ2.6
Topic 10: Organic chemistry, 10.1 Fundamentals of organic chemistry, 10.2 Functional group chemistry, Topic 5: Energetics/thermochemistry, 5.2 Hess’s Law
The photochemical chlorination of methane can occur at low temperature.
The overall equation for monochlorination of methane is:
CH4(g) + Cl2(g) → CH3Cl(g) + HCl(g)
Calculate the standard enthalpy change for the reaction, ΔH θ, using section 12 of the data booklet.
17M.3.SL.TZ1.2
Core, Topic 8: Acids and bases, 8.2 Properties of acids and bases
A class was determining the concentration of aqueous sodium hydroxide by titrating it with hydrochloric acid, whilst monitoring the pH of the solution. The sodium hydroxide solution was added into a glass beaker from a measuring cylinder and the hydrochloric acid added using a burette. One group of students accidentally used a temperature probe rather than a pH probe. Their results are given below.
Volume of aqueous NaOH = 25.0 ± 0.5 cm3
Concentration of HCl = 1.00 ± 0.01 mol dm−3
a. Deduce why more heat was produced in mixture B than in mixture A. [1]
b. Deduce why the temperature is higher in mixture C than in mixture D. [1]