Miscellaneous and Chapter 11: Formulae and Equations

Question 1

What are half equations?

Answer 1

Oxidation/reduction equations written from the point of view of a specific element, showing the electrons it gains during a reaction (e.g. S²⁻ - 2e⁻ => S)

Question 2

How do you determine how many atoms 2 elements will share when they bond covalently?

Answer 2

Each atom will share the amount that is required for all atoms to have a full outer electron shell

Question 3

How do you draw an ionic bond?

Answer 3

1. Draw however many ions of each element as you need to make the end product neutral
2. Draw square brackets around each ion and write the charge in the upper right corner

Question 4

How do you draw a covalent bond?

Answer 4

1. Write the element symbol and draw a circle (representing the outer shell) around it
2. Work out how many electrons will need to be shared to give both atoms a full outer shell
3. Draw one atom’s electrons as dots and the other’s as crosses

Question 5

How do you draw metallic bonding?

Answer 5

Draw some large circles with plusses inside them and an between them equal number of smaller circles with minuses inside them

Question 6

How do you balance an equation?

Answer 6

Make sure that both sides of the equation have the same number of atoms of each element

Question 7

What is the difference between an alkali and a base?

Answer 7

A base is any substance that reacts with an acid to form water and a salt. An alkali is a special type of base that dissolves in water to form OH- ions

Question 8

Element + oxygen =>

Answer 8

Oxide of element (e.g. iron + oxygen => iron oxide)

Question 9

Compound + oxygen =>

Answer 9

Oxides of each element in compound (e.g. methane + oxygen => carbon dioxide + water)

Question 10

Water + metal =>

Answer 10

Metal hydroxide + hydrogen (for alkali metals) (e.g. water + sodium => sodium hydroxide + hydrogen)

Question 11

Acid + metal =>

Answer 11

Salt + hydrogen (e.g. Hydrochloric acid + magnesium => Magnesium chloride + hydrogen)

Question 12

Acid + metal oxide =>

Answer 12

Salt + water (e.g. sulfuric acid + copper oxide => copper sulfate + water)

Question 13

Acid + metal hydroxide =>

Answer 13

Salt + water (e.g. nitric acid + potassium hydroxide => potassium nitrate + water)

Question 14

Acid + metal carbonate =>

Answer 14

Salt + water + carbon dioxide (e.g. Hydrochloric acid + calcium carbonate => Calcium chloride + water + carbon dioxide)

Question 15

Acid + ammonia =>

Answer 15

Ammonium salt (e.g. nitric acid + ammonia => ammonium nitrate)

Question 16

How do you balance equations?

Answer 16

Change the number of molecules of each substance on both sides of the equation until the number of atoms of each substance on both sides is equal