Acids, Bases and salts

Question 1

What is pH

Answer 1

It tells you if the solution is acidic, alkaline or neutral.

Question 2

Acid

Answer 2

Anything with a pH of less than 7. Goes from yellow to red. Formed by hydrogen ions (H+) when dissolved in water.

Question 3

Base or alkali

Answer 3

Anything with a pH of greater than 7. Goes from blue to light purple. Alkaline is formed by hydroxide ions (OH-) dissolved in the water.

Question 4

Indicator

Answer 4

Used to find out the pH of solution. It is a dye that changes color depending on if it is acid or alkaline.

Question 5

Universal indicator

Answer 5

Is a combination of dyes which gives you a different color at the different pH values.

Question 6

(aq)

Answer 6

Ions are dissolved in water (aqueous)

Question 7

(l)

Answer 7

liqid

Question 8

(g)

Answer 8

gas

Question 9

(s)

Answer 9

solid

Question 10

Neutralisation

Answer 10

An acid reacts with a base to form a salt and water.
acid + base = salt + water
Ions H+ + OH- = H2O

Question 11

Salts

Answer 11

Can be made from metals, metal oxides, metal hydroxides, metal carbonates or ammonia.
acid + metal = slat + hydrogen
acid + metal oxide/ metal hydroxide = salt + water

Question 12

Reactivity of metals with acids

Answer 12

By monitoring the rate of hydrogen production when they react with an acid.

Question 13

Name of the salt produced

Answer 13

First part of the name of the slat come from the metal and second part from an acid

Question 14

What are bases?

Answer 14

All metal oxides and metal hydroxides. Soluble hydroxides are called alkalies.

Question 15

Uses of slat

Answer 15

Ammonium nitrate used as fertilizer. Contains nitrogen essential for plants.

Question 16

Precipitation

Answer 16

Used to make insoluble salt. It is done by mixing the appropriate amount of one reactant and another.

Question 17

Crystallization

Answer 17

Process used to get solid salt crystals from salt solution.

Question 18

Soluble salt

Answer 18

Can be made by reacting hydrochloric or sulphuric acid with metals, insoluble bases and alkalis

Question 19

Making a soluble salt from insoluble base

Answer 19

By adding a excess of insoluble base or metal to an acid, the excess base is the filtered out.

Question 20

Making soluble salt from an alkali

Answer 20

Indicator is used to show when the reaction ends.

Question 21

Uses of precipitation

Answer 21

Can be used as a way of extracting undesired ions from solution. E.g. lead ions from drinking water or metal ions from sewage water before it is discharged to a river.

Question 22

Titration

Answer 22

An experiment that shows how much reactant is needed to react completely with a certain volume of another reactant.

Question 23

Phenolphthalein

Answer 23

Is pink in alkalis but colorless in acids.

Question 24

Methyl orange

Answer 24

Is yellow in alkalis but red in acids

Question 25

Why is universal indicator not a suitable to use in a titration?

Answer 25

It changes color gradually. For titration you need indicator that will give you a define color change.

Question 26

Ammonia dissolves in water to...

Answer 26

produce an alkaline solution. It is used to produce ammonium salts.

Question 27

Insoluble slat can be made by...

Answer 27

reacting solutions of two soluble slats together.

Question 28

Precipitate

Answer 28

An insoluble solid formed by a reaction taking place in solution.