Zadanie 1a
(i) Write a balanced equation for the reaction of calcium with oxygen to form calcium oxide. (ii) Calcium oxide is a basic oxide. Identify an element in period 3 that forms an amphoteric oxide.
Chemistry HL Paper 2, May 2022, TZ1
Zadania wzorowane na pytaniach z tego arkusza: te same umiejętności, format i punktacja, inne dane i kontekst. Treści arkusza IB nie publikujemy.
Dodaj cały arkusz do zestawuZadanie 1b
In an experiment, calcium turnings were heated strongly in a crucible with a lid. The following data were recorded: (i) Calculate the amount of calcium, in mol, that was used. (ii) Determine the percentage uncertainty in the final mass of product. (iii) Assume…
- Tabela do uzupełnienia
Zadanie 1c
A student heated 3.492 g of calcium turnings in a crucible with a lid and obtained 4.490 g of solid product. If the product is assumed to be calcium oxide only, the percentage yield is 92 %. (i) Evaluate whether the formation of calcium nitride, rather than…
Zadanie 1d
The presence of calcium nitride in the product can be demonstrated by adding water. The nitride is hydrolysed to form calcium hydroxide and ammonia. (i) Calculate coefficients that balance the equation for the reaction: __ Ca3N2(s) + __ H2O(l) →…
Zadanie 1e
Most oxide ions are . (i) State the number of protons, neutrons and electrons in this ion. (ii) Some oxide ions are . State the term that describes the relationship between and . (iii) The…
Zadanie 1f
Atoms were once thought to be the smallest particles of matter, impossible to divide. Suggest two pieces of evidence that show an atom has an internal structure.
Zadanie 1g
State the type of bonding in calcium, nitrogen and calcium nitride, and how the valence electrons produce each type of bonding.
Zadanie 2a
Suggest an experiment that shows that zinc is more reactive than copper, giving the observation that would confirm this.
Zadanie 2b
A block of zinc attached to a steel structure acts as a sacrificial anode. (i) Calculate the standard cell potential, in V, of a cell made from zinc and steel half-cells. Use section 19 of the data booklet and take the standard electrode potential of steel to…
Zadanie 2c
The graph shows the volume of hydrogen produced when a small piece of zinc reacts with a large excess of 2.0 mol dm−3 hydrochloric acid. (i) Deduce from the graph how the rate of reaction depends on the amount of zinc present. (ii) The rate is…
- Materiał graficzny
Zadanie 3a
(i) Deduce the expression for the equilibrium constant, Kc, for this equation. (ii) State how the use of a catalyst affects the value of Kc. (iii) Using the reaction quotient, Q, explain why raising the pressure at constant temperature increases the…
- Materiał graficzny
Zadanie 3b
The enthalpy change of the reaction is one factor that influences the position of equilibrium. (i) Determine the enthalpy change, ΔH, for the production of methanol, in kJ, using bond enthalpies. Use section 12 of the data booklet. (ii) Outline why a…
- Materiał graficzny
Zadanie 3c
The standard free energy change, ΔG⊖, for the production of methanol is −44.0 kJ at 298 K and the standard enthalpy change, ΔH⊖, is −114 kJ. (i) State, with a reason, whether the production of methanol is spontaneous at 298 K.…
- Materiał graficzny
Zadanie 4a
State the relationship between CH3NH3+ and CH3NH2 in terms of the Brønsted-Lowry theory.
Zadanie 4b
A sample of methylamine gas, volume 120.0 dm3 at 295.0 K and 102.0 kPa, dissolves in water and the solution is made up to 2.50 dm3. Determine the concentration of the solution, in mol dm−3. Use sections 1 and 2 of the…
Zadanie 4c
The base dissociation constant of methylamine at 298 K is Kb = 4.4 × 10−4. (i) Calculate the concentration of hydroxide ions in a methylamine solution with pH = 11.6. Use sections 1 and 2 of the data booklet. (ii) Calculate the concentration, in…
Zadanie 4d
Aluminium salts form acidic solutions owing to equilibria such as: Al3+(aq) + H2O(l) ⇌ Al(OH)2+(aq) + H+(aq) Comment on the role of Al3+ in forming the Al(OH)2+ ion, in acid-base terms.
Zadanie 4e
Al(OH)2+ is a complex ion, yet aluminium is not classed as a transition metal. Contrast aluminium with chromium, Cr, for one characteristic chemical property of transition metals, apart from the formation of complex ions. Property: Comparison:
Zadanie 5a
(i) State the IUPAC name of Compound B. (ii) Both compounds are liquids at room temperature. Identify the strongest intermolecular force between molecules of Compound B. (iii) State how many σ (sigma) bonds and how many π (pi) bonds one molecule of Compound A…
- Materiał graficzny
Zadanie 5b
Compound B can also be made by the hydration of an alkene. The same reaction also gives a smaller amount of the isomer 3-methylbutan-2-ol, (CH3)2CHCH(OH)CH3. (i) Draw the structural formula of the alkene that is needed. (ii) Explain why the reaction…
- Materiał graficzny
Zadanie 5c
Deduce what would be observed when each of Compound B and pentan-2-ol is warmed separately with acidified aqueous potassium dichromate(VI).
- Materiał graficzny
Zadanie 5d
Bromoethane can be converted into ethanol: CH3CH2Br + HO− → CH3CH2OH + Br− (i) Identify the type of reaction. (ii) Outline what must be true of a collision between reacting particles for a reaction to occur. (iii) Explain the mechanism of this…
Zadanie 6a
Ozone, O3, is an allotrope of oxygen found in the upper atmosphere. (i) Complete the boxes with arrows to show the ground-state electron configuration of an oxygen atom. (ii) Deduce a Lewis (electron dot) structure of O3 in which every atom has…
- Materiał graficzny
Zadanie 6b
Benzene reacts with bromine in the presence of an iron(III) bromide catalyst to form bromobenzene. The reaction is an electrophilic substitution in which the electrophile is Br+. (i) Draw the structural formula of the carbocation intermediate formed as…