Chemical Changes Flashcards
How can you measure the pH of a solution?
Using an indicator or pH probe.
What is an acid?
An acid is a substance that forms aqueous solutions with a pH less than 7. Acids form H+ ions in water.
What is a base?
A base is a substance with a pH greater than 7.
What is an alkali?
An alkali is a base that dissolves in water to form a solution with a pH greater than 7. Alkalis form OH- ions in water.
What is the name for the reaction between acids and bases?
Neutralisation
Acid + Base →
Acid + Base → Salt + Water
What are strong acids?
Strong acids are acids that ionise completely in water. All acid particles dissociate to release H+ ions.
What is pH?
The measure of the concentration of hydrogen ions.
Acid + Metal Oxide →
Acid + Metal Oxide → Salt + Water
Acid + Metal Hydroxide →
Acid + Metal Hydroxide → Salt + Water
Acid + Metal Carbonate →
Acid + Metal Carbonate → Salt + Water + Carbon Dioxide
Acid + Metal →
Acid + Metal → Salt + Hydrogen
Metal + Water →
Metal + Water → Metal Hydroxide + Hydrogen
What is oxidisation?
Gain of oxygen or loss of electrons.
What is reduction?
Loss of oxygen or gain of electrons.
Which ions move to the cathode?
Positive ions, as the cathode has a negative charge.
What is an electrolyte?
A liquid or solution that can conduct electricity.
What is the test for chlorine?
Chlorine bleaches damp litmus paper, turning it white.
What is the test for hydrogen?
Htdrogen makes a “squeaky pop” with a lighted splint.
What is the test for oxygen?
Oxygen will relight a glowing splint.
