Further Additional Chemistry

Question 0

How do you remove temporary hardness?

Answer 0

Via boiling, when heated calcium hydrocarbonate decomposes to form calcium carbonate which is insoluble.

Question 1

What is water hardness caused by?

Answer 1

Calcium and magnesium ions

Question 2

How can forms of ‘hardness’ be softened?

Answer 2

Adding washing soda (sodium carbonate, Na2CO3). Added carbonate ions react with Ca2+ and Mg2+. & ion exchange columns, they include lots of sodium/hydrogen ions. These exchange them for calcium or magnesium ions.

Question 3

What colour is a lithium flame?

Answer 3

Crimson

Question 4

What colour is a sodium flame?

Answer 4

Yellow

Question 5

What colour is a potassium flame?

Answer 5

Lilac

Question 6

What colour is a calcium flame?

Answer 6

Red

Question 7

What colour is a barium flame

Answer 7

Green

Question 8

What is an endothermic reaction?

Answer 8

Takes in energy from surroundings.

Question 9

What is an exothermic reaction?

Answer 9

Gives out energy to surroundings

Question 10

What is the functional group of carboxylic acids?

Answer 10

COOH

Question 11

What’s the functional group of esters?

Answer 11

COO

Question 12

How are esters formed?

Answer 12

Alcohol + carboxylic acid -> ester + water

Question 13

How are ethanoic acids formed?

Answer 13

Ethanol + oxygen -> ethanoic acid + water

Question 14

What’s the functional group of alcohol?

Answer 14

OH

Question 15

What’s an equilibrium?

Answer 15

In a reversible reaction both directions of the reaction are happening at the same rate so cancel each other out.

Question 16

How is ammonia created?

Answer 16

N2 + 3H2 2NH3 or Nitrogen + hydrogen (+ heat) ammonia

Question 17

How is water treated?

Answer 17

Screening, removal of solids and microbes, filtration, chlorination. (Carbon and silver sometime used in homes)

Question 18

What is a halogen?

Answer 18

A non-metal with coloured vapours.

Question 19

What is carboxylic acid used for?

Answer 19

Longer chains used in soaps and detergents, used to make esters, solvents (although makes solution acidic)

Question 20

What do carboxylic acids do when in contact with water?

Answer 20

Dissolve to produce acidic solutions. When dissolved ionises and releases H+ ions but not a lot/completely so forms weak acids.

Question 21

how do you test for carbonates?

Answer 21

acid + carbonate -> salt +water + carbon dioxide

Question 22

how do you test for halide ions?

Answer 22

add dilute nitric acid followed by silver nitrate solution

Question 23

what precipitate does chloride give off?

Answer 23

white precipitate of silver chloride

Question 24

what precipitate does bromide give off?

Answer 24

cream precipitate of silver bromide

Question 25

what precipitate does iodide give off?

Answer 25

yellow precipitate of silver iodide

Question 26

how do you test for ive+ ions?

Answer 26

add metal to a flame and check the flame colour

Question 27

what colour is a calcium2+ precipitate?

Answer 27

white

Question 28

what colour is a copper2+ precipitate?

Answer 28

blue

Question 29

what colour is an iron2+ precipitate?

Answer 29

green

Question 30

what colour is an iron3+ precipitate?

Answer 30

brown

Question 31

what colour is a magnesium2+ precipitate?

Answer 31

white

Question 32

what colour is an aluminium3+ precipitate?

Answer 32

white at first and then re-dissolves

Question 33

how do you measure a fuels energy?

Answer 33

using calorimetry. record initial temp of water in a can and weigh spirit burner and lid. Then light it until the temperature is 50 degrees. put out the flame and measure final temperature and weight of spirit burner and lid.

Question 34

How do you test for metal ions that are positive?

Answer 34

Use the precipitate test. Add few drops of sodium hydroxide to the mystery compound to turn it insoluble

Question 35

What colour is a fluorine gas?

Answer 35

Yellow

Question 36

What colour is a chlorine gas?

Answer 36

Dense green gas

Question 37

What colour is a bromine gas?

Answer 37

Red-brown volatile liquid

Question 38

What colour is a iodine gas?

Answer 38

A dark grey crystalline solid or a purple vapour