Chemical Changes

• What is the general reaction for the formation of metal oxides?

  Metals + oxygen -> metal oxides
• Why are reactions that form metal oxides known as oxidation reactions?

  Because the metals gain oxygen during the reaction
• What is the definition of reduction in terms of oxygen?

  Reduction is the loss of oxygen
• What is the definition of oxidation in terms of oxygen?

  Oxidation is the gain of oxygen
• What happens to metal atoms when they react with other substances?

  Metal atoms form positive ions
• How is the reactivity of a metal related to its tendency to form positive ions?

  The reactivity of a metal increases with its tendency to form positive ions
• What is the order of reactivity for the metals potassium, sodium, lithium, calcium, magnesium, zinc, iron, and copper?

  • Potassium
  • Sodium
  • Lithium
  • Calcium
  • Magnesium
  • Zinc
  • Iron
  • Copper
• How does potassium react with water?

  Potassium reacts violently with water
• How does sodium react with water?

  Sodium reacts very quickly with water
• How does lithium react with water?

  Lithium reacts quickly with water
• How does calcium react with water?

  Calcium reacts more slowly with water
• How does calcium react with dilute acid?

  Calcium reacts very quickly with dilute acid
• How does magnesium react with dilute acid?

  Magnesium reacts quickly with dilute acid
• How does zinc react with dilute acid?

  Zinc reacts fairly slowly with dilute acid
• How does iron react with dilute acid?

  Iron reacts more slowly with dilute acid
• How does copper react with dilute acid?

  Copper reacts very slowly with dilute acid
• Which non-metals are often included in the reactivity series?

  Hydrogen and carbon
• What can a more reactive metal do in relation to a less reactive metal?

  A more reactive metal can displace a less reactive metal from a compound
• Why is gold found in the Earth as the metal itself?

  Because gold is very unreactive
• How are most metals found in the Earth?

  Most metals are found as compounds that require chemical reactions to extract the metal
• How can metals less reactive than carbon be extracted from their oxides?

  By reduction with carbon
• What does reduction involve in terms of oxygen?

  Reduction involves the loss of oxygen
• What does the acronym OIL RIG stand for?

  Oxidation Is Loss and Reduction Is Gain (of electrons)
• What should the charges on each side of an ionic equation do?

  The charges should add up to the same number
• What do acids react with to produce a salt and hydrogen?

  Some metals
• What is produced when an acid reacts with a metal?

  A salt and hydrogen
• What type of reactions occur when acids react with metals?

  Redox reactions
• How can you identify which substances are oxidized and reduced in a redox reaction?

  By looking at electrons gained and lost (following OIL RIG)
• What is the ionic equation for magnesium reacting with hydrochloric acid?

  Mg -> Mg$^{2+}$ + 2e$^{-}$
• What does the reaction of hydrogen ions produce in a redox reaction?

  H$_{2}$
• In the reaction between magnesium and hydrochloric acid, what happens to magnesium?

  It is oxidized
• In the reaction between magnesium and hydrochloric acid, what happens to hydrogen?

  It is reduced
• What is the general equation for the neutralization of acids by alkalis and bases?

  • Acid + Alkali -> Salt + Water
  • Acid + Base -> Salt + Water
• What do acids produce when neutralized by metal carbonates?

  Salts, water, and carbon dioxide
• What is the general equation for the reaction of an acid with a metal carbonate?

  Acid + Metal Carbonate -> Salt + Water + Carbon Dioxide
• What determines the type of salt produced in acid and alkali reactions?

  • The acid used:
  • Hydrochloric acid (HCl) produces chlorides (XCl)
  • Nitric acid (HNO$_{3}$) produces nitrates (XNO$_{3}$)
  • Sulfuric acid (H$_{2}$SO$_{4}$) produces sulfates (XSO$_{4}$)
  • The positive ions in the base, alkali, or carbonate
• What must the charges on the positive ion from the base and the negative ion from the acid do?

  They must add up to zero
• What is the resulting salt when sodium hydroxide reacts with sulfuric acid?

  Na$_{2}$SO$_{4}$
• How can soluble salts be made from acids?

  1. Add a solid insoluble substance to the acid until it dissolves.

  2. Neutralization is indicated when excess solid sinks to the bottom.

  3. Filter out excess solid, evaporate some water, and leave to evaporate slowly (crystallization).
• What do acids produce in aqueous solutions?


  H$^{+}$ ions