Chemistry separate science [paper 2]

• What is the pH range of acids?


  1. 7
• What do acids produce when they react with metals?

  Hydrogen gas
• Name a common example of an acid.


  Lemon juice
• How do you classify acids based on their pH?

  Lower values indicate stronger acids
• What is the pH range of bases?

  1. 14
• What do bases produce when they react with acids?

  Salts and water
• What is a key property of bases regarding litmus paper?


  They turn red litmus blue
• What type of salt is formed from a strong acid and a strong base?

  Neutral salt (pH 7)
• What is the taste of most salts?

  Salty
• How do you classify salts based on their acid-base origin?

  By their pH and the strength of acid/base
• What happens to salts when dissolved in water?

  They conduct electricity
• What is the pH of a salt formed from a strong acid and a weak base?

  Slightly acidic salt (pH < 7)
• What is a key property of acids regarding taste?


  They taste sour
• What is a key property of bases regarding texture?


  They feel slippery
• How do acids and bases differ in their effect on litmus paper?


  Acids turn blue litmus red, bases turn red blue
• If a substance tastes bitter and feels slippery, what is it likely to be?

  Base
• What are the key properties of acids?

  • Taste sour
  • React with metals to produce hydrogen gas
  • Turn blue litmus red
  • pH between 0 and 7
  • Neutralize bases to form salts
• What are the key properties of bases?

  • Taste bitter
  • Feel slippery
  • React with acids to form salts and water
  • Turn red litmus blue
  • pH range 7-14
• What are the properties of salts?

  • Taste salty
  • Conduct electricity when dissolved in water
  • High melting points
• What is formed by neutralizing sulfuric acid with ammonia?

  A new salt
• What characterizes a weak base?

  Partially dissociates in water
• What is the pH scale used for?

  • Categorizes substances as acids, bases, or salts
  • Ranges from 0 to 14
  • Indicates hydrogen ion concentration
• What role does hydrochloric acid play in digestion?

  Aids in breaking down proteins
• Which substance can be used to neutralize acidic soil?

  Calcium hydroxide
• What is the focus of the video discussed?

  AQA GCSE chemistry paper 2
• What does the rate of reaction indicate?

  How quickly reactants are used or products made
• How can we calculate the mean rate of reaction?

  Quantity of reactant used divided by time
• What are the units for measuring the rate of reaction?

  Grams per second, cm³ per second, moles per second
• What does a steep curve on a reaction graph indicate?

  A high rate of reaction
• What is the first method to experimentally determine the rate of reaction?

  Measure change in mass of reaction mixture
• What equipment is used to measure the change in mass?

  A balance and a stopwatch
• Why do we use a cotton wool at the top of the conical flask?

  To allow gases to escape without losing substances
• How do we calculate the rate of reaction using mass change?

  Rate equals change in mass divided by change in time
• What is the second method to measure the rate of reaction?

  Measure volume of gas produced
• What units are used when measuring the volume of gas produced?

  cm³ per second
• How do we find the mean rate of reaction from a graph?

  Change in amount divided by change in time
• What is the mean rate of reaction between 0 and 30 seconds if the change in amount is 60?

  2 cm³ per second
• How do we calculate the rate of reaction at a specific point on a graph?

  Draw a tangent and find its gradient
• What does Collision Theory explain?

  How factors affect the rate of reaction
• What is activation energy?

  The minimum energy needed for a reaction