Year 10 Science Study Guide Acids and Bases Introduction to this unit This unit is important because: We are used to grouping objects or substances together that have similar physical properties. We can also group substances that have similar chemical properties – for example the families of ‘acids’ and ‘bases’. These families of chemicals are found in many places, including at home, in nature and in our bodies. Specific Learning Outcomes By the end of this unit… …all students should be able to … Distinguish between pure substances, elements, mixtures and compounds in the context of acids and bases. Name two common laboratory acids and two common laboratory bases. Describe the general reaction between common laboratory acids with most metals and metal carbonates. Discuss the use of acids and bases in household substances in terms of physical and chemical properties. …most students should be able to… 1. Identify substances as acidic, basic or neutral on the basis of: a) Results of testing with common indicators (universal indicator and litmus). b) Common physical (feel, taste) and chemical properties (i.e. reactions). 2. Relate the degree of acidity or basicity/alkalinity of a substance to the pH scale. 3. Describe some common substances found at home and in the laboratory* as either acidic or basic. 4. Describe the arrangement of electrons in energy levels or shells. 5. Explain that atoms react (change) if they can so they achieve full electron shells. 6. Describe the formation of metal ions and common monatomic negative ions in terms of loss or gain of electrons. 7. Write the ionic formula of compounds involved in acid-base reactions given a reference table of named ions. 8. Use the context of reactions to explain ion formation and formulae of compounds 9. Describe and write word equations for the reactions (reactants and products) of acids with: a. Metals; and b. Metal carbonates c. Bases (limited to hydroxides of metals), i.e. neutralisation. 10. Write chemical symbol equations to describe a reaction. Page 1 of 2 Link the properties of acids and bases to how they are used in society or occur in nature e.g. of contexts, soil pH, cosmetics, swimming pool chemistry, toothpaste, acid rain, insect bites, cooking. Extension …in addition, some students will progress further and will be able to: Relate the pH scale to the relative concentrations of hydrogen and hydroxide ions present in a solution. Explain neutralisation in terms of hydrogen and hydroxide ions in water. Balance a chemical symbol equation to describe a reaction. Investigate at least one factor that affects the rate (speed) of an acid-base reaction (surface area, concentration or temperature). Science Essential Vocabulary Through the activities in this unit you should be able to define and understand: Acid/acidic Base/basic Alkali/alkaline Neutral Indicator Litmus Universal Indicator pH Concentrated Dilute React Reaction Reactant(s) Product(s) Mixture Element Compound Pure Substance Neutralisation Salt(s) Ion(s) Positive ion Negative ion Electron(s) *Common lab acids Hydrochloric acid Sulfuric acid *Common lab bases Sodium hydroxide Ammonium solution Carbonates Sodium carbonate Calcium carbonate *Sodium hydrogen carbonate (baking soda) Page 2 of 2 Names of metals and metal ions: Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Copper Names of negative ions: Chloride Sulfate Hydroxides Carbonate