AQA GCSE Chemistry Paper 1: Atoms & Chemical Reactions (Topics 1-5 Intro)

10 Question-and-Answer flashcards covering atoms, elements, compounds, chemical formulas, and conservation of mass, aligned with AQA GCSE Chemistry Paper 1 introductory content.

What are all substances made of?

Atoms

Where are different types of atoms represented?

In the periodic table using chemical symbols.

Define an element in terms of atoms.

A substance that contains only one type of atom.

What is a compound?

A substance composed of two or more different types of atoms chemically bonded together.

Give the chemical formula for water and state its atomic ratio.

H₂O; two hydrogen atoms for every one oxygen atom.

In a chemical formula, what does the absence of a subscript number after a symbol imply?

An invisible ‘1’—there is one atom of that element.

How can chemical reactions be represented?

By word equations and by symbol (balanced) chemical equations.

State the Law of Conservation of Mass as it applies to chemical reactions.

Atoms are neither created nor destroyed, so the number of each type of atom is the same on both sides of the equation.

Why must chemical equations be balanced?

To ensure the same number of each type of atom appears on both the reactant and product sides, satisfying the conservation of mass.

In GCSE Chemistry, what tiers and courses does Topics 1-5 cover?

Higher & Foundation tier for Combined Trilogy and Triple (Separate) Chemistry.