Chemistry 0620 · IGCSE · Rate of reaction

Rate of reaction — practice question

A measured portion of dilute nitric acid is poured onto pieces of limestone in a conical flask. The conical flask is set on a balance, and the decrease in mass is recorded. A separate sample of nitric acid with a different concentration is then tested in the same way. Every other condition is left unchanged. The change in mass in $1$ minute for each nitric acid concentration is shown. At concentration $0.5\,\text{mol dm}^{-3}$, the loss in mass is $0.15\,\text{g}$, and at concentration $1.0\,\text{mol dm}^{-3}$, the loss in mass is $0.25\,\text{g}$. Which row gives the description and explanation of the results for $1.0\,\text{mol dm}^{-3}$ nitric acid compared with $0.5\,\text{mol dm}^{-3}$ nitric acid?

  • Adecrease in reaction rate; decrease in particle collision energy
  • Bdecrease in reaction rate; increase in particle collision rate
  • Cincrease in reaction rate; increase in particle collision rate
  • Dincrease in reaction rate; increase in particle collision rate and collision energy

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