Acids & Bases Flashcards
Describe how universal indicator (UI), can be used to estimate the pH of a solution.
UI changes with pH 1-4 is red, 5 & 6 are orange and yellow, 7 is green, 8 & 9 are green-blue, 10 & 11 are purple.
Recall the colour changes with litmus
Litmus is red in acid, blue in alkali and purple in neutral solutions
What is an alkali?
An alkali is a soluble base.
Describe neutralisation.
An acid can be neutralised by a base or alkali, or vice versa, the other way around
What do indicators use colour change for?
Sudden or gradual changes of pH by using colour changes over different pH ranges
What is the equation for neutralisation?
acid + base –> salt + water
Recall that in solution, all acids contain what?
All acids contain H+ ions.
What causes pH?
pH of an acid is determined by the concentration of H+ ions
Explain why an acid is neutralised by an alkali in terms of the ions present
Acids contain H+, alkalis contain OH–, neutralisation is
Explain why metal oxides and metal hydroxides neutralise acids.
They react to form neutral salts and water.
Carbonates neutralise acids to give what?
Water, a salt and carbon dioxide.
Construct word equations to show the neutralisation of acids by bases
Acid + Base à Salt + Water
Construct word equations to show the neutralisation of acids by carbonates
Acid + Carbonate –> Salt + Water + CO2
Which salt is produced when magnesium oxide is neutralised by sulphuric acid?
Magnesium sulphate
Predict the name of the salt produced sodium carbonate is neutralised by nitric acid
Sodium carbonate
