Chemistry HL
Collaborative sciences project preparation
- 1.
A hypothetical chemistry-physics team compares energy-storage routes for delivering 12.0 kWh of useful electricity. Route H uses 30.0 kWh input electricity; route B uses 15.0 kWh. Calculate both overall efficiencies. Explain why a comparison using 1 kg of each storage material instead could be misleading, and name one further chemistry-related factor the team should investigate before choosing a route.
[3 marks] - 2.
In a hypothetical shared water study, the chemistry team reports a pH probe reading of 6.0 while a second team reports 7.0 for an apparently identical sample. Propose a joint calibration check, identify two pieces of metadata needed to establish whether the measurements are comparable, and explain why simply averaging to pH 6.5 does not resolve the discrepancy.
[3 marks] · no calculator - 3.
A hypothetical project group favours a hydrogen bus proposal because it has no direct CO2 exhaust. A chemistry member raises hydrogen-production emissions and a physics member raises conversion losses. Propose a negotiated evidence-gathering plan, state one ethical boundary for reporting a provisional recommendation, and give one concrete reflection question about interdisciplinary cooperation.
[3 marks] · no calculator - 4.
For a hypothetical chemistry-physics team rehearsal, route A uses 10 kWh of electricity and route B uses 16 kWh for the same delivered transport service. Non-electric lifecycle emissions within an agreed boundary are 5.0 kg CO2e for A and 2.0 kg CO2e for B. Let grid intensity be g kg CO2e per kWh, identical for both. Form total-emission expressions, find the crossover g, and compare routes at g=0.20. Explain how the team should qualify a recommendation if future g is unknown.
[5 marks] - 5.
In a hypothetical shared energy-storage review, a chemistry member finds '90% material recovery' for a battery process, while a physics member has '60% energy efficiency' for the same process. No definitions or denominators accompany either number. A draft multiplies 0.90 by 0.60 to claim '54% sustainable'. Explain two distinct denominator questions the team must resolve, propose a traceable joint revision of the draft, and identify an environmental issue neither percentage necessarily captures. No actual study is being cited.
[4 marks] · no calculator