GCSE WJEC Chemistry- acids, salts and bases

group of elements present in alkalis

OH → Hydroxide

1-6 PH scale

strong + weak end

acid

1= strong

6= weak

7 PH scale

neutral

8-14 PH scale

strong + weak end

alkali

8= weak

14= strong

element present in acids

H → Hydrogen

acid turns litmus paper

red

alkali turns litmus paper

blue

standard neutralisation equation (between hydrogen and hydroxide ions)

H⁺ + OH⁻ → H₂O

base

any metal oxide/ hydroxide

1st part salt name

2nd part salt name

1st= comes from equation

2nd= acid used

acid + metal

salt + hydrogen

acid + base

salt + water

acid + alkali

salt + water

acid + carbonate

salt + water + CO₂

hydriochloric acid gives…

chlorides

sulfuric acid gives…

sulfates

nitric acid gives…

nitrates

how to identify sulfate ions

test with barium chloride → creates white preticipate

what is neutralisation?

when an acid and an alkali cancel each other out

Signs of a reaction taking place

fizzing/ bubbling/ temp change/ colour change

Why add alkali in excess when creating crystals

so no acid is left

max temp in neutralization reaction

when all acid/ alkali is neutralized

testing if a solution is acidic

add sodium carbonate and if carbon dioxide is formed its acidic

silver nitrate solution test results

chloride- white preticipate
bromide- cream preticipate
iodide- yellow preticipate
(smokers ceiling)