GCSE Combined Science Flashcards
6 cards from real GCSE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 GCSE Combined Science flashcards as text
What is the difference between a covalent bond and a metallic bond?
Answer: A covalent bond involves sharing electrons between non-metals; metallic bonds involve delocalised electrons in a lattice of metal ions
Covalent bonds form when non-metal atoms share electrons. Metallic bonds involve a lattice of positive metal ions surrounded by a 'sea' of delocalised (free-moving) electrons. The electrostatic attraction between ions and electrons holds metals together.
What is the difference between series and parallel circuits?
Answer: In series, current flows in one path; in parallel, current can flow through multiple paths simultaneously
In a series circuit, components are connected end-to-end in a single loop; current is the same throughout. In a parallel circuit, components have separate branches; current splits between branches, but voltage across each branch is the same.
What is natural selection?
Answer: The process by which organisms with favourable traits are more likely to survive, reproduce, and pass on those traits
Natural selection (Darwin's theory): individuals with traits better suited to their environment are more likely to survive and reproduce, passing on advantageous genes. Over generations, favourable traits become more common.
What is the equation for calculating work done?
Answer: Work = force × distance
Work done (measured in Joules) = Force (N) × Distance (m). Work is done when a force causes displacement in the direction of the force. If no displacement occurs, no work is done.
What is the difference between a physical and a chemical change?
Answer: Physical changes are always reversible; chemical changes produce new substances and are usually irreversible
In a physical change, the substance itself doesn't change (melting ice, dissolving sugar) — it is usually reversible. In a chemical change, new substances are formed (burning, rusting, digestion) — usually irreversible.
What does the pH scale measure?
Answer: The acidity or alkalinity of a solution (1 = strong acid, 7 = neutral, 14 = strong alkali)
The pH scale runs from 0 to 14. Values below 7 are acidic (lower = more acidic), pH 7 is neutral, and values above 7 are alkaline (higher = more alkaline). Universal indicator or a pH probe measures pH.