Chemistry yr10 mock - Chapter 4 - Reactions of Acids

What is an acid

Molecule which produces H+ ions when dissolved in water

Give the formula of; Hydrochloric acid, sulfuric acid and nitric acid

-HCl

-H2SO4

-HNO3

What is a base

Substance which reacts with an acid by bonding to H+ ions in the acid

3 types of insoluble bases

Metal oxides, (some) metal hydroxides and (some) metal carbonates

What is an alkali

A base which is soluble in water and releases hydroxide ions (OH-)

Give the formula of 3 common lab alkalis

NaOH (sodium hydroxide)

KOH (potassium hydroxide)

NH3 (ammonia)

What is pH

Measure of acidity/alkalinity of solution

Give two methods to measure pH

Universal indicator or a pH probe

What is a neutral solution

Equal concentration of H+ and OH- ions

What is the name for an acid-base reaction

Neutralisation

General equation for acid reacting with a metal oxide

Acid + metal oxide → salt + water

General equation for acid reacting with a metal carbonate

Acid +metal carbonate → salt + water + carbon dioxide

General equation for acid reacting with a metal hydroxide

Acid + metal hydroxide → salt + water

Ionic equation for acid reacting with an alkali

H+ (aq) + OH- (aq) → H20 (l)

General equation for acid reacting with a metal

Acid + metal → salt + hydrogen

Why may metals not react with a dilute acid

They aren’t reactive enough

Where do the positive ions in a salt come from

The base/metal that reacts with the acid

Formula of the ion present in salts from hydrochloric acid

Cl-

Formula of the ion present in salts from sulfuric acid

SO4 (2-)

Formula of the ion present in salts from nitric acid

NO3-

In order to prepare a pure, dry sample of a soluble salt, what do you react with the acid

Solid, insoluble substance like a metal/insoluble base

Step 1 of soluble salt preparation

Solid is added to the acid until it is in excess & solid is visible

How can step 1 of soluble salt preparation be sped up

Acid can be heated

Step 2 of soluble salt preparation

Filtration is used to remove excess solid and leave a solution of the salt in the filtrate

Step 3 of soluble salt preparation

Gently heat using a water bath or electric heater, causing some of the water to be evaporated

Step 4 of soluble salt preparation

Saturated salt solution is then left to cool so that crystals can form

2 methods of drying crystals after crystallisation

-Filtration then pat dry

-Leave to allow all water to evaporate