Topic 10 (Acids and Bases) Flashcards
What is an acid?
A substance that produces H+ ions when dissolved in water
What is a base?
A substance that neutralises an acid forming salt and water.
What is an alkali?
A base dissolved in water, producing hydroxide ions.
Write the general equation for the reaction between acids and reactive metals.
Acid + metal -> salt + hydrogen gas
Describe how you would test for hydrogen gas
Place a lighted splint in the gas. If hydrogen is present, the splint will be extinguished with a pop sound.
Which metals do not react with dilute acids?
Copper, silver, gold, platinum
Which metals react explosively with dilute acids?
Potassium, sodium, calcium
Write the general equation for the reaction between acids and carbonates.
Carbonate + acid -> salt + carbon dioxide + water
Describe how you would test for carbon dioxide gas
Bubble the gas through limewater. If carbon dioxide is present, a white precipitate will be observed
Is effervescence observed when acids react with metals and carbonates?
Yes
Write the general equation for the neutralisation reaction between an acid and a base.
acid + base -> salt + water
What is a weak acid?
An acid that dissociates partially when dissolved in water, producing a low concentration of hydrogen ions.
What is a weak alkali?
An alkali that dissociates partially when dissolved in water, producing a low concentration of hydroxide ions.
Acids, neutral substances and bases have what pH ranges?
Acids have pH < 7, neutral substances have pH = 7, bases have pH > 7
What are the physical properties of acids?
Acids taste sour and acidic solutions conduct electricity.