2.2.2 Measuring Rates

• Higher temperature increases the reaction rate
• Match the method with what it measures:

  Disappearance of reactants ↔️ Decrease in reactant concentration

  Appearance of products ↔️ Increase in product concentration

  Change in physical properties ↔️ Changes in color or volume
• What physical properties can be used to measure reaction rates?

  Color or temperature
• The faster the gas is produced, the higher the reaction rate.


  True
• Steps in the mass loss method for measuring reaction rate:

  1️⃣ Weigh reactants before mixing

  2️⃣ Place mixture in open container

  3️⃣ Measure mass at regular intervals

  4️⃣ Plot mass decrease over time
• Controlling factors such as concentration and temperature allows chemists to optimize reaction rates


  True
• A larger surface area of reactants increases the reaction rate


  True
• Measuring the disappearance of reactants involves tracking the decrease in their concentration
• A faster production of gas indicates a higher reaction rate


  True
• The mass loss method is suitable for reactions where a gas is released
• In spectrophotometry, changes in absorbance over time provide a quantitative measure of the reaction rate
• What does the rate of a reaction refer to?

  Speed of conversion
• Order the factors affecting reaction rates from most to least impact

  1️⃣ Temperature

  2️⃣ Concentration of reactants

  3️⃣ Surface area of reactants

  4️⃣ Presence of a catalyst
• The mass loss method tracks the decrease in mass of reactants over time
• The gas produced in the mass loss method escapes from an open
• In the color change method, the rate of the color change indicates the reaction rate
• How does the concentration of reactants affect the reaction rate?

  Higher concentration increases rate
• What is the role of a catalyst in a reaction?

  Lower activation energy
• What does the slope of a graph in reaction rate measurements represent?

  Reaction rate
• Higher concentration of reactants increases the reaction rate.


  True
• The presence of a catalyst increases the reaction rate without being consumed itself.

  True
• The rate of a reaction can be determined by monitoring the decrease in the concentration of reactants
• What type of reaction is the volume of gas produced method suitable for?

  Reactions producing gases
• In the mass loss method, the reaction mixture is placed in an open container to allow gas to escape
• A catalyst increases the reaction rate without being consumed
• A higher concentration of reactants increases the reaction rate
• Match the method for measuring reaction rate with what it measures:

  Disappearance of reactants ↔️ Decrease in concentration

  Appearance of products ↔️ Increase in concentration

  Change in physical properties ↔️ Changes in color, volume, temperature
• Measuring the volume of gas produced is useful for reactions that produce a gaseous product
• Steps for using the mass loss method to measure reaction rate:

  1️⃣ Weigh reactants before mixing

  2️⃣ React in open container for gas escape

  3️⃣ Measure mass at regular intervals

  4️⃣ Plot mass loss to determine rate
• Match the method with its description:

  Color change ↔️ Reaction produces observable color change

  Spectrophotometry ↔️ Measures absorbance changes quantitatively
• Increasing the temperature always increases the reaction rate


  True
• A catalyst is consumed during a reaction

  False
• For what type of reactions is measuring the volume of gas produced particularly useful?

  Reactions producing gas
• What does the mass loss method measure to determine the rate of reaction?

  Decrease in mass
• Match the method with its description:

  Color Change ↔️ Visual observation of reaction

  Spectrophotometry ↔️ Quantitative measurement of absorbance
• Spectrophotometry is a more quantitative method than color change for measuring reaction rates.


  True
• A larger surface area of solid reactants increases the reaction rate by exposing more molecules to react.


  True
• Steps for analyzing data collected from rate measurements:

  1️⃣ Plot the data over time

  2️⃣ Interpret the graph

  3️⃣ Determine the slope of the line

  4️⃣ Relate the slope to the reaction rate
• What is the rate of a reaction defined as?

  Speed of reactant conversion
• What are chemists able to do by controlling reaction rate factors?

  Optimize reaction speeds