Loading...
Acids release hydrogen ions in aqueous solution; alkalis provide hydroxide ions. Their neutralisation forms water: H+ + OH⁻ → H2O. Acids with reactive metals form a salt and hydrogen; acids with carbonates form a salt, water and carbon dioxide. Hydrochloric acid makes chlorides, sulfuric acid sulfates and nitric acid nitrates. Strong and weak describe extent of ionisation, while concentrated and dilute describe the amount dissolved per volume.
Video by Cognito. The video’s own board label is retained; follow the specification reference and scope notes on this lesson for assessed content.
Viewing focus: Predict products of acid reactions
After watching, attempt these questions before opening the answers. You can also use the written lesson below.
After watching 1: What forms from H+ and OH⁻?
Water. This is the ionic neutralisation equation.
After watching 2: Which gas is produced by acid and carbonate?
Carbon dioxide. It turns limewater cloudy.
What you'll be able to do
Acids release hydrogen ions in aqueous solution; alkalis provide hydroxide ions. Their neutralisation forms water: H+ + OH⁻ → H2O. Acids with reactive metals form a salt and hydrogen; acids with carbonates form a salt, water and carbon dioxide. Hydrochloric acid makes chlorides, sulfuric acid sulfates and nitric acid nitrates. Strong and weak describe extent of ionisation, while concentrated and dilute describe the amount dissolved per volume.
Warm dilute sulfuric acid gently and add copper oxide until some remains, ensuring all acid reacts. Filter off the excess insoluble oxide. Carefully concentrate the filtrate, allow it to cool, then filter, wash and dry the crystals. Excess oxide can be removed by filtration, unlike excess soluble alkali. Evaporating the solution aggressively to complete dryness is unnecessary and can damage the product. Use the laboratory’s approved heating and protective procedures.
When both acid and alkali are soluble, a titration finds the reacting volumes. Use a pipette for a fixed aliquot and a burette for variable addition. Add indicator, swirl and approach the endpoint dropwise. Repeat to obtain concordant titres, excluding the rough trial from an appropriate mean. If pure salt is needed, repeat using the known volumes without indicator, then crystallise. Titration calculations connect concentrations, volumes and balanced-equation ratios.
Attempt these problems on paper before opening the worked reasoning. Explain your steps as well as giving a final answer.
Common mistakes to avoid
Key takeaways
Question 1: Why add excess copper oxide when making copper sulfate?
Excess solid removes the need to guess the exact endpoint.
Check the assessed scope and practical or mathematical requirements.
An external explanation or interactive activity to use alongside the lesson. It may include extension material.
Close the notes and answer from memory. Revisit any explanation you cannot yet reconstruct.
Test yourself
Answer a few questions, then review anything you missed.
Start with the quiz above to check the key ideas. You can also choose another topic from the practice library.