Chemistry Ka4 Flashcards
How does a sodium atom change into a sodium ion?
By losing two electrons
Under what conditions will an ionic compound conduct electricity?
Molten or dissolved in water (aqueous)
What is an electrolyte?
The liquid or solution which is able to conduct electricity
What is the positive electrode called?
Anode
What is the negative electrode called?
Cathode
What is the equation for the positive electrode when the molten compound used is copper chloride (chlorine Cl₂)
2Cl⁻ - 2e⁻ –> Cl₂
What is the equation for the product at the negative electrode when the molten compound used is copper chloride (copper Cu)?
Cu² ⁺ + 2e⁻ –> Cu
When passing electricity through a molten salt what ions move to the negative electrode?
The positive ions
What two substances are formed when molten sodium chloride is broken down by electricity?
Sodium and chlorine
How is sodium chloride found?
In rock salt and dissolved in oceans
What is the formula for sodium chloride?
NaCl
What can all charged particles do?
Freely move
What is chlorine used for?
Disinfectant in pools
What is hydrogen used for?
Rocket fuel
What is sodium hydroxide used for?
In bleach
Name the ions in sodium chloride solution
Sodium ions
Chlorine ions
Explain sodium chloride (molten)
Contains only sodium ions and chloride ions.
The products are sodium and chlorine
Explain sodium chloride (solution/dissolved in water)
Contains only sodium ions, chloride ions, hydrogen ions m, hydroxide ions. The products are chlorine, hydrogen and sodium hydroxide
Explain what happens during electrolysis of hair
The positive electrode is connected by a patch of skin. The negative electrode is connected to the hair. The body fluid is a solution containing sodium chloride. The electricity causes the electrolysis of a small amount of this solution. Hydrogen ions move to the negative electrode because they have a positive charge. Chlorine gas is produced. A strong alkali called hydroxide is formed around the hair follicle. This helps to break down the follicle
What is electrolysis?
The decomposition of a substance to give simpler substances.
What must the substance being electrolysed be?
An ionic compound
What is the substance being decomposed during electrolysis called?
The electrolyte
What happens to the electric current during electrolysis?
It enters and leaves the electrolyte by conducting rods called the electrodes
What must be for electrolysis to occur?
The electrolyte must be in liquid form so that the ions are free to move. The negative ions move towards the anode. When they get there they lose electrons to form neutral atoms. The positive ions move towards the cathode, there they gain electrons to form a neutral charge atoms
When the solid used is sodium chloride: State the liquid used, name of solution made, ions present in the solution, ions at positive electrode, ions at negative electrode :
Water, sodium chloride, sodium : chloride : hydrogen : hydroxide ions , chloride (Cl⁻) : hydroxide (OH⁻), sodium (Na ⁺) hydrogen (H ⁺)
How do you work out the products at the negative electrode?
Hydrogen is produced if the metal is more reactive than hydrogen. If not, the metal is produced
How do you find the products at the positive electrode?
Oxygen is produced unless the solution contains halide ions (chloride, bromide etc) when the halogen is produced
