1.5.3 Measuring Reaction Rates

• Increased surface area increases the reaction rate.


  True
• Why does increasing the temperature raise the reaction rate?

  More effective collisions
• Tracking pH changes measures the change in acidity or alkalinity
• Water displacement measures gas volume by water displaced
• Mass change is used to measure the change in mass of reactants or products
• Give an example of a reaction where mass change is used to measure the reaction rate.

  Decomposition of CaCO3
• What does the reaction rate measure?

  Speed of product formation
• How does higher concentration affect the reaction rate?

  Increases it
• What is measured when monitoring gas evolution in a reaction?

  Volume of gas
• Give an example of a reaction where monitoring gas evolution is used.

  Decomposition of hydrogen peroxide
• A gas syringe allows direct volume measurement of gas produced.


  True
• What happens to the mass of the reaction mixture during the decomposition of calcium carbonate?

  Decreases
• What does the mass change method measure in reaction rate experiments?

  Change in mass
• What does tracking pH changes measure in reaction rate experiments?

  Acidity or alkalinity
• What does the Beer-Lambert law describe in colorimetry?

  Absorbance and concentration
• Titration is an analytical technique used to determine the concentration
• What type of solution is added to the unknown during titration to signal the endpoint?

  Titrant
• What does analyzing the shape and slope of a time vs. concentration graph reveal in reaction rate experiments?

  Reaction order
• A higher temperature increases the reaction rate
• Catalysts increase the reaction rate
• Measuring color change detects changes in color intensity due to the formation or disappearance of colored compounds.


  True
• What are gas collection techniques used to measure?

  Reaction rates
• Describe how water displacement is used to collect gas.

  Gas displaces water
• Match the gas collection technique with its description:

  Water Displacement ↔️ Measures volume by water displaced

  Gas Syringe ↔️ Captures gas for direct measurement
• Another method for measuring reaction rate is to track the change in mass
• In the decomposition of calcium carbonate, the mass of the reaction mixture will decrease as carbon dioxide gas is released
• The molar absorptivity in the Beer-Lambert law is represented by the symbol ε
• What instrument is used to perform colorimetry?

  Colorimeter
• What signals the endpoint in a titration?

  Indicator color change
• The reaction between HCl and NaOH produces NaCl and H2O

  True
• The reaction rate constant measures the intrinsic speed of a reaction

  True
• By analyzing the shape and slope of a graph, you can determine the reaction order and the reaction rate constant
• Monitoring gas evolution measures the volume of gas produced during a reaction


  True
• Colorimetry relies on the principle that the color of a solution is related to the substances it contains and their concentrations

  True
• Steps to perform colorimetry

  1️⃣ Prepare sample solutions of known concentrations

  2️⃣ Calibrate the colorimeter using a blank solution

  3️⃣ Measure the absorbance of each sample solution

  4️⃣ Plot a calibration curve

  5️⃣ Determine the concentration of unknown samples
• A calibration curve in colorimetry plots absorbance against concentration


  True
• Steps in the titration process

  1️⃣ Add the unknown solution to a flask

  2️⃣ Add indicator solution

  3️⃣ Add titrant from a burette

  4️⃣ Record the volume of titrant used

  5️⃣ Calculate the concentration of the unknown
• A graph of time vs. concentration in reaction rate experiments shows the change in concentration of reactants or products over time
• Which type of graph tracks the volume of gas produced during a reaction over time?

  Time vs. Volume of Gas