topic 6

• What is produced when magnesium reacts with hydrochloric acid?

  H₂ gas
• What is the first step in the magnesium and HCl reaction experiment?

  Add dilute hydrochloric acid to a flask
• How should the flask be sealed after adding magnesium ribbon?

  With cotton wool
• What does measuring the mass at regular intervals indicate in the magnesium and HCl experiment?

  The mass lost during the reaction
• What happens to the rate of reaction when the concentration of acid is increased?

  The rate of reaction increases
• What is formed when sodium thiosulfate reacts with hydrochloric acid?

  A yellow precipitate of sulfur
• How is the disappearance of the black cross used in the sodium thiosulfate experiment?

  To measure the time taken for the reaction
• What should be kept constant when repeating the sodium thiosulfate experiment?

  The concentration of one chemical at a time
• What does a higher concentration of sodium thiosulfate indicate about the reaction time?

  It results in a quicker reaction
• What is the formula for calculating the mean rate of reaction?

  Rate = total change in y / total time
• How do you find the mean rate of reaction from a graph?

  Calculate the gradient of the line
• What does drawing a tangent to a curve help determine?

  The rate of reaction at a specific point
• What is the rate of reaction at 3 seconds if the gradient is calculated as 0.09 g/s?

  0.09 g/s
• What is the first step in measuring the rate of a reaction that produces a gas?

  Use a mass balance to measure mass
• Why is measuring the change in mass considered accurate?

  It provides precise mass readings
• What is a disadvantage of using a mass balance in gas reactions?

  Gas escapes into the room
• What is the rate of reaction formula?

  Rate = amount of reactant used / time
• What happens to the rate of reaction when the surface area of a solid increases?

  The rate of reaction increases
• How does increasing temperature affect particle collisions?

  Particles collide more frequently and energetically
• What is the role of a catalyst in a chemical reaction?

  It speeds up the reaction without being consumed
• What is activation energy?

  The minimum energy needed for a reaction
• How does collision theory explain reaction rates?

  More collisions increase the reaction rate
• What factors affect the rate of a chemical reaction?

  Concentration, surface area, temperature, catalyst
• What is the effect of increasing the concentration of a solution on reaction rate?

  It increases the reaction rate
• Why do reactions occur faster at higher temperatures?

  Particles have more kinetic energy and collide more
• What happens to the rate of reaction when a solid is powdered?

  The rate of reaction increases
• How does a catalyst lower the activation energy?

  By providing an alternative reaction pathway
• What is the effect of a catalyst on the overall reaction equation?

  It is not included in the equation
• What is the significance of collision frequency in reaction rates?

  More collisions lead to faster reactions
• How can you measure the rate of a reaction that produces a precipitate?

  By timing how long it takes for a mark to disappear
• What is the relationship between the steepness of a reaction rate graph and the reaction speed?

  Steeper lines indicate faster reactions
• What does a plateau in a reaction rate graph indicate?

  The reaction has completed
• How do different initial amounts of reactants affect reaction graphs?

  They change the steepness of the graph
• What is the effect of temperature on particle movement?

  Particles move faster at higher temperatures
• Why is it important to keep certain factors constant in reaction experiments?

  To ensure valid and reliable results
• What is the significance of measuring the time for a color change in reactions?

  It indicates the speed of the reaction
• What is the purpose of using a gas syringe in measuring reaction rates?

  To measure the volume of gas produced
• How does the presence of a catalyst affect the energy of collisions?

  It lowers the activation energy needed
• What happens to the rate of reaction if the surface area of a solid reactant is increased?

  The rate of reaction increases
• What is the effect of increasing pressure on gas reactions?

  It increases the rate of reaction