Chemistry Ka4 Flashcards Preview

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Flashcards in Chemistry Ka4 Deck (27):
1

How does a sodium atom change into a sodium ion?

By losing two electrons

2

Under what conditions will an ionic compound conduct electricity?

Molten or dissolved in water (aqueous)

3

What is an electrolyte?

The liquid or solution which is able to conduct electricity

4

What is the positive electrode called?

Anode

5

What is the negative electrode called?

Cathode

6

What is the equation for the positive electrode when the molten compound used is copper chloride (chlorine Cl₂)

2Cl⁻ - 2e⁻ --> Cl₂

7

What is the equation for the product at the negative electrode when the molten compound used is copper chloride (copper Cu)?

Cu² ⁺ + 2e⁻ --> Cu

8

When passing electricity through a molten salt what ions move to the negative electrode?

The positive ions

9

What two substances are formed when molten sodium chloride is broken down by electricity?

Sodium and chlorine

10

How is sodium chloride found?

In rock salt and dissolved in oceans

11

What is the formula for sodium chloride?

NaCl

12

What can all charged particles do?

Freely move

13

What is chlorine used for?

Disinfectant in pools

14

What is hydrogen used for?

Rocket fuel

15

What is sodium hydroxide used for?

In bleach

16

Name the ions in sodium chloride solution

Sodium ions
Chlorine ions

17

Explain sodium chloride (molten)

Contains only sodium ions and chloride ions.
The products are sodium and chlorine

18

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

19

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

20

What is electrolysis?

The decomposition of a substance to give simpler substances.

21

What must the substance being electrolysed be?

An ionic compound

22

What is the substance being decomposed during electrolysis called?

The electrolyte

23

What happens to the electric current during electrolysis?

It enters and leaves the electrolyte by conducting rods called the electrodes

24

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

25

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 ⁺)

26

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

27

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