Rate and extent of chemical chnage

• How is the rate of reaction calculated?

  Rate of reaction = amount of reactant used/time
• What is the formula for rate of reaction in moles?

  Rate of reaction (mol/s) = moles/time
• Name three common ways of measuring the rate of reaction.

  Loss in mass, volume of gas, time for opacity
• How is the rate of reaction measured by monitoring mass loss?

  Record mass decrease over time intervals
• How is the rate of reaction measured by monitoring gas volume?

  Use a gas syringe to measure gas volume
• How is the rate of reaction measured by monitoring the disappearance of a cross?

  Time taken for a cross to disappear in solution
• How do you find the rate of reaction at time t from a graph?

  Find the tangent at time t on the curve
• What are five factors affecting the rate of a chemical reaction?

  Concentration, pressure, surface area, temperature, catalysts
• What is the collision theory?

  Reactions occur when particles collide with sufficient energy
• Describe the effect of increasing temperature on the rate of reaction.

  Higher temperature increases kinetic energy and collision frequency
• Describe the effect of increasing concentration on the rate of reaction.

  Higher concentration leads to more frequent collisions
• Describe the effect of increasing pressure of a gas on the rate of reaction.

  Higher pressure increases collision frequency among gas molecules
• Describe the effect of increasing surface area on the rate of reaction.

  Smaller pieces increase surface area and collision frequency
• What is a catalyst and how does it work?

  A catalyst speeds up reactions without being consumed
• What is an enzyme?

  An enzyme is a biological catalyst
• What is a reversible reaction?

  A reaction where products can form reactants again
• When is dynamic equilibrium reached?

  When forward and reverse reactions occur at the same rate
• Describe Le Chatelier’s Principle.

  System responds to counteract changes and restore equilibrium
• Describe the effect of changing the concentration of reactants and products on equilibrium.

  Changing concentration shifts equilibrium to restore balance
• Describe the effect of changing temperature on equilibrium.

  Increased temperature favors endothermic reactions
• Describe the effect of changing pressure on equilibrium.

  Increased pressure shifts equilibrium to fewer gas molecules
• Describe the effect of a catalyst on equilibrium.

  A catalyst speeds up both forward and backward reactions