Reliable methods for measuring reaction rate by gas production

Steps:

• Reaction rate is measured by monitoring CO2 output over time quantitatively.
• Method 1 records mass loss every 2 minutes, proportional to CO2 evolved.
• Method 2 records gas volume, directly indicating moles of CO2 via syringe or burette.
• Method 3 counts bubbles, which varies in size and frequency unreliably.

Why C is correct:

• C identifies methods 1 and 2 as suitable, enabling rate calculation from mass/volume vs. time graphs, where 1 mol CO2 corresponds to 44 g loss or 24 dm³ at STP per mole.

Why the others are wrong:

• A: Excludes method 2, limiting options despite its direct volume measurement.
• B: Relies solely on method 3, inaccurate due to inconsistent bubble sizes not reflecting true gas volume.
• D: Includes method 3, introducing subjective error unsuitable for precise rate data.

Final answer: C