Chemical changes- part 2 Flashcards
What is a redox reaction?
reactions where both oxidation and reduction are taking place eg- displacement reaction
What is electrolysis?
Means splitting up with electrolysis
How does electrolysis work?
An electrical current is passed through an electrolyte and the ions move towards the electrodes, where they react and the compound decomposes
Where do the postitive ions move to in electrolysis and what happenes?
The cathode (negative), they are reduced
Where do the negative ions move towards and what happens?
The anode (positive), they are oxidised
What is the equation at the positive electrode?
2O(2-)= O2+4e-
What is the equation at the negative electrode?
AL3+ + 3e- = AL
What can electrolysis be used to extract?
Metals from their ores
What is the half equation at the negative electrode in aqueous soultions?
2H+ + 2e- = H2
What is the equation at the positive electrode in aqueous solutions?
2Cl- = Cl2 + 2e-
In aqueous solutions, what happens at the cathode?
Hydrogen gas will be produced if the metal formed is more reactive then hydrogen
What happens at the anode in aqueous solutions?
OH- and if halide ions present, molecules of chlorine or iodine or bromine will form
