IGCSE Chemistry Definitions Quiz

Phase Changes

• Melting: Transition from solid to liquid.
• Freezing: Transition from liquid to solid.
• Condensation: Gas or vapor converts to liquid.
• Evaporation: Liquid transforms into gas or vapor.

Temperatures and Points

• Melting Point: Specific temperature where solid becomes liquid.
• Freezing Point: Specific temperature where liquid turns into solid.
• Boiling Point: Temperature at which a liquid vaporizes at atmospheric pressure.

Mixtures and Separation Techniques

• Diffusion: Movement of particles from high to low concentration.
• Filtration: Method to separate insoluble solids from liquids.
• Filtrate: Liquid that has passed through a filter.
• Fractional Distillation: Process that separates liquids based on different boiling points.

Solutions

• Solute: Substance being dissolved in a solvent.
• Solution: Mixture created when solute dissolves in solvent.
• Solvent: Liquid that dissolves the solute.

Chemical Processes

• Galvanization: Protective coating of iron using zinc to prevent rusting.

Atomic Structure

• Atomic Number/Proton Number: Counts number of protons in an atom.
• Atom: Smallest unit of an element with distinct properties.
• Mass Number/Nucleon Number: Total of protons and neutrons in an atom.
• Nucleus: Core of an atom, housing protons and neutrons.
• Isotope: Variants of an element with the same protons but different neutrons.

Types of Matter

• Element: Pure substance consisting of one type of atom.
• Compound: Substance formed by chemical union of two or more different atoms.
• Mixture: Combination of different components not chemically bonded.

Periodic Table Organization

• Group: Columns indicating the number of electrons in the outer shell.
• Period: Rows indicating the number of electron shells in an atom.

Chemical Bonding

• Ionic Bonding: Strong attraction between oppositely charged ions.
• Covalent Bonding: Attraction formed by shared pairs of electrons and atomic nuclei.
• Metallic Bonding: Attraction between positive metal ions and delocalized electrons.

Particles and Molecules

• Ion: Charged particle from ionic bonding, unequal protons and electrons.
• Molecule: Neutral particle formed through covalent bonding.

Reaction Dynamics

• Rate of Reaction: Change in concentration of reactants/products over time; more frequent collisions yield a faster reaction.
• Catalyst: Substance that accelerates a reaction without altering itself; reduces activation energy.
• Enzyme: Biological catalyst, e.g., Amylase.

Mass and Moles

• Relative Formula Mass: Total atomic masses of elements in a compound.
• Mole: Amount of substance containing Avogadro's number (6.02 x 10^23) of molecules or atoms.

Energy Changes in Reactions

• Exothermic Reaction: Reaction that releases heat; indicated by negative ΔH.
• Endothermic Reaction: Reaction that absorbs heat; indicated by positive ΔH.

pH Scale and Bases

• pH: Scale from 0 to 14 indicating acidity, neutrality, or alkalinity of a solution.
• Base: Substance with pH above 7, reacting with acids to produce salts.