Acids, Alkalis And Salts COPY COPY

Question 1

What is the pH scale

Answer 1

The pH scale, from 0-14 , can be used to classify solutions we strongly acidic, weakly acidic, neutral, weakly alkaline or strongly alkaline

Question 2

What is the use of the universal indicator

Answer 2

To measure the approximate pH value of a solution

Question 3

What are acids

Answer 3

Sources of hydrogen ions , H+

Question 4

What are alkalis

Answer 4

Sources of hydroxide ions, OH-

Question 5

Hydrochloric acid + metal ->

Answer 5

Metal chloride salt + hydrogen

Question 6

Sulfuric acid + metal ->

Answer 6

Metal sulphate + hydrogen

Question 7

Hydrochloric acid + metal oxide ->

Answer 7

Metal chloride salt + water

Question 8

Nitric acid + metal oxide ->

Answer 8

Metal nitrate salt + water

Question 9

Sulphuric acid + metal oxide ->

Answer 9

Metal sulfate + water

Question 10

Hydrochloric acid + metal carbonate ->

Answer 10

Metal chloride salt + water + carbon dioxide

Question 11

Nitric acid + metal carbonate ->

Answer 11

Metal nitrate salt + water + carbon dioxide

Question 12

Sulphuric acid + metal carbonate ->

Answer 12

Metal sulfate + water + carbon dioxide

Question 13

All common sodium, potassium and ammonium salts are

Answer 13

Soluble

Question 14

All nitrates are

Answer 14

Soluble

Question 15

Common chlorides are………..except…….

Answer 15

Soluble except solve chloride

Question 16

Common sulfates are …….. Except ……..

Answer 16

Soluble except barium and calcium

Question 17

Common carbonates are ………except ……….

Answer 17

Insoluble except sodium, potassium and ammonium

Question 18

Describe experiments to prepare insoluble salts using precipitation reactions

Answer 18

To make silver chloride, mix together silver nitrate solution and sodium chloride solution. -The precipitate of silver chloride is then removed by filtration -washed with a little distilled water (to remove traces of the potassium nitrate solution) -and left to dry in a warm place

Question 19

Describe experiments to prepare soluble salts from acids

Answer 19

Dilute sulphuric acid is added to an excess of magnesium. (Mg + H2SO4 -> MGSO4 + H2) The left over magnesium is filtered off and the mixture is boiled down slowly to concentrate. When it is cooled, crystals will form, these can be blotted dry with a piece of paper

Question 20

Nitric sulfuric and hydrochloric acids make soluble salts with

Answer 20

Most metals

Question 21

Ammonium, potassium and sodium make soluble sale with

Answer 21

Acids

Question 22

What is used to distinguish between acid and alkaline solutions

Answer 22

Indicators litmus, phenolphthalein and methyl orange

Question 23

How to use universal indicator

Answer 23

Universal indicator can come in two forms, either in a liquid solution of ethanol or in a paper that has been soaked in the indicator solution. Either drop some universal indicator into the solution or drop the liquid under test onto the paper

Question 24

What colour does red litmus paper turn in the presence of alkali

Answer 24

Red litmus paper turns blue in the presence of alkali.

Question 25

What colour does blue litmus paper turn in the presence of acid

Answer 25

Blue litmus paper turns red in the presence of acid

Question 26

What colour does phenolphthalein turn in alkalis

Answer 26

Phenolphthalein goes pink in alkalis

Question 27

What colour is methyl orange in alkalis

Answer 27

Methyl orange is yellow for alkalis

Question 28

What colour is methyl orange for acids

Answer 28

Methyl orange is red for acids

Question 29

What are the solubility rules

Answer 29

i) all common sodium, potassium and ammonium salts are soluble ii) all nitrates are soluble iii) common chlorides are soluble, except silver chloride iv) common sulfates are soluble, except those of barium and calcium v) common carbonates are insoluble, except those of sodium, potassium and ammonium

Question 30

Describe experiments to carry out acid-alkali titrations

Answer 30

-using a pipette, put 25.0cm3 of the alkali solution into a conical flask. -add a few drops of an indicator, such as methyl orange -put the acid into a burette and note the initial reading -add the acid to the alkali until the indicator just changes colour (e.g methyl orange turns from yellow to orange) -note the final reading of acid in the burette -subtract the initial reading from the final reading to obtain the volume of acid added. This is the volume required to neutralise 25.0cm3 of the acid.

Question 31

What type of salts are made from precipitation reactions

Answer 31

Insoluble salts are made from precipitation reactions.

Question 32

What is a precipitate

Answer 32

A precipitate is an insoluble solid that is made by a chemical reaction that takes place in an aqueous solution

Question 33

What is necessary to make an insoluble salt

Answer 33

To make an insoluble salt it is necessary to mix together two separate aqueous solutions. One solution must contain the required positive ion and the other solution the required negative ion.

Question 34

What is a titration

Answer 34

A titration is a method of finding out exactly the volume of one solution that is required to react with a given volume of another solution