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Chemistry 2

also known as Acids and Bases

Table of Contents

Hey there! Please be advised if you’re an boi this doesn’t exactly match your textbook! I’ve tried to keep similar concepts together so if you can’t find something, feel free to use the textbook, or use that neat little search bar up the top there! Thanks!

Acids and Bases on BBC Bitesize (National 5)

basically the better version of this

Common properties


Acids are corrosive. They taste sour, and can be used to react with other substances.

Acids are chemicals with a pH < 7. Acids contain hydrogen ions (H⁺). When acids are diluted with water the concentration of H⁺ ions in the solution is reduced, and it’s pH increases towards 7 (neutral pH).


Bases are sometimes corrosive. They are bitter, slippery, and/or soapy. Bases that can be dissolved in water are called alkalis.

Bases are chemicals with a ph > 7. Bases contain hydroxide ions (OH⁻). When bases are diluted with water the concentration of OH⁻ ions in the solutions is reduced, and it’s pH decreases towards 7 (neutral pH).

Acids have a pH less than 7. Bases have a pH greater than 7. Remember it as a comes before b. Acids come before bases on the pH scale.

Table of Acids and Bases you should know

Test yourself on Quizlet

Acid name Formula Ionic Formula PH Level
Hydrochloric acid HCl H⁺(aq) Cl⁻(aq) 2
Sulfuric acid H₂SO₄ 2H⁺(aq) SO₄²⁻(aq) 2
Nitric acid HNO₃ H⁺(aq) NO₃⁻(aq) 2
Alkali name Formula Ionic Formula PH Level
Sodium hydroxide NaOH Na⁺(aq) OH⁻(aq) 13
Calcium hydroxide Ca(OH)₂ Ca2⁺(aq) 2OH⁻(aq) 13
Potassium hydroxide KOH K⁺(aq) OH⁻(aq) 13

pH values

Water and neutral solutions has a pH level of 7.

pH scale

Differentiate between strong and weak

You can test for how acidic or basic is using a number of ways. This includes using universal indicator to estimate pH, or test the reactivity of solutions in water.

Neutralisation Reactions

Test yourself on Quizlet

When you mix an acid and a base together, a chemical reaction occurs! The mixture will get warmer and it usually follows this formula:

acid + base –> salt + water

Metal oxides and metal hydroxides

Both metal oxides and metal hydroxides are bases

metal oxide + acid –> salt + water
metal hydroxide + acid –> salt + water

Metal carbonates

When metal carbonates react with acids, they work the same way as metal oxides and hydroxides but on the reactant side there is also carbon dioxide gas

metal carbonate + acid –> salt + water + carbon dioxide


copper oxide + hydrochloric acid –> copper chloride + water
CuO + 2HCl –> CuCl₂ + H₂O

Note how chloride in copper chloride on the reactant side has a subscript 2. This is to balance the chemical equation. As copper(II) has a valency of 2 we use the crossover method as covered in Chemistry 1 and multiplechloride by two. To balance the equation on both sides we add a 2 in front of HCl which makes sure there are equal atoms on both the reactant and product side.

copper carbonate + nitric acid –> copper nitrate + water + carbon dioxide
CuCO₃ + 2HNO₃ –> Cu(NO₃)₂ + H₂O + CO₂

What happens when acids react with…

Acids react with bases

When acids and bases react, they neutralise and produce salt and water.

Acids react with metals

When acids and metals react, they produce salt and hydrogen gas.

Acids react with carbonates

When acids and carbonates react, they produce salt, water and carbon dioxide.

Extra information

Reactivity: tendency to lose or gain electrons

Reactivity of metal DECREASES from left to right, and INCREASES from up to down. Alkali metals in Group 1 have the highest reactivity, while noble gases in Group 8 are typically unreactive.

Footnotes and Other Notes

  1. Acids and Bases on BBC Bitesize - 

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