weak topics!!

• What do acids produce in water?

  Protons (H+ ions)
• How do strong acids behave in water?

  They ionise completely, releasing H+ ions
• What characterizes weak acids in solution?

  They do not fully ionise, establishing equilibrium
• Where does the position of equilibrium lie for weak acids?

  To the left, favoring undissociated acid
• What does pH measure?

  Concentration of H+ ions in solution
• How does pH change with H+ ion concentration?

  Decrease of 1 pH increases H+ by a factor of 10
• How does the pH of strong and weak acids compare at the same concentration?

  Strong acid has a lower pH than weak acid
• What does acid strength indicate?

  Portion of acid molecules that ionise
• What does acid concentration measure?

  Amount of acid in a certain volume of water
• What is a dilute acid?

  An acid that is not very concentrated
• How does pH change with increasing acid concentration?

  pH decreases with increasing acid concentration
• What are bases in relation to metal oxides and hydroxides?

  Metal oxides and hydroxides are bases
• What are alkalis?

  Soluble bases that react with acids
• What do all metal oxides and hydroxides produce when reacting with acids?

  Salt and water
• What do acids and metal carbonates produce?

  Salt, water, and carbon dioxide
• What is the reactivity series?

  Order of metals based on their reactivity
• How is a metal's reactivity determined?

  By how easily it loses electrons
• What happens when metals react with water or acids?

  They lose electrons and form positive ions
• What is the order of reactivity for metals from most to least reactive?

  Potassium, sodium, lithium, calcium, magnesium, carbon, zinc, iron, hydrogen, copper
• Why are carbon and hydrogen included in the reactivity series?

  To show how metals react with them
• How can metals less reactive than carbon be extracted?

  By reduction with carbon
• What happens when metals more reactive than hydrogen react with acids?

  They produce salt and hydrogen gas
• How does the speed of a reaction relate to metal reactivity?

  More reactive metals react faster
• What do metals react with water to produce?

  Metal hydroxide and hydrogen gas
• Why must metals be separated from their ores?

  They are usually found as compounds
• What is oxidation in relation to metals?

  Formation of metal oxides from reactions with oxygen
• What is a redox reaction?

  A reaction that involves electron transfer
• What does reduction mean in metal extraction?

  Removal of oxygen from the metal ore
• How can some metals be extracted using carbon?

  By reduction of their ores with carbon
• What happens during the electrolysis of molten ionic compounds?

  They are broken up into their elements
• What is the role of electrodes in electrolysis?

  Conduct electricity and react with ions
• Why can molten ionic compounds be electrolysed?

  Because ions can move freely
• What materials should electrodes be made of during electrolysis?

  Inert materials that do not react
• What happens at the negative electrode during electrolysis?

  Positive ions are reduced to the element
• What happens at the positive electrode during electrolysis?

  Negative ions are oxidized to the element
• What additional ions are present in aqueous solutions during electrolysis?

  Hydrogen ions and hydroxide ions from water
• What determines which ions are discharged at the electrodes in electrolysis?

  Relative reactivity of all ions in solution
• What happens at the negative electrode if H+ and metal ions are present?

  Hydrogen gas is produced if metal is more reactive
• What happens at the positive electrode if OH- and halide ions are present?

  Molecules of halogens are formed
• What happens if no halide ions are present at the positive electrode?

  OH- ions are discharged, producing oxygen gas