GCSE Chemistry Paper 1 Flashcards

GCSE chemistry paper one flashcards.

Proton

Subatomic particle with a positive charge and a relative mass of 1. Found in the nucleus of an atom.

Neutron

Subatomic particle with no charge and a relative mass of 1. Found in the nucleus of an atom.

Electron

Subatomic particle with a negative charge and negligible mass. Orbits the nucleus in electron shells.

Atomic number

Number of protons in an atom. Determines the element.

Mass number

Sum of the number of protons and neutrons in an atom. Used to identify isotopes.

Isotopes

Atoms with the same number of protons but different numbers of neutrons. Example: Carbon-12 and Carbon-14

Ions

Atoms that have gained or lost electrons, resulting in a net charge. Positive ions (cations) and negative ions (anions).

Compounds

Substances in which particles are chemically joined together. Have a fixed ratio of atoms. Example: Water (H2O)

Mixtures

Substances in which particles are simply mixed together, not chemically joined. Can be separated easily. Example: Saltwater

Crystallization

Separation technique that involves forming crystals from a solution. Used to purify solids.

Filtration

Separation technique used to separate insoluble solids from liquids. Uses filter paper.

Chromatography

Separation technique used to separate different substances based on their different solubilities. Example: Separating dyes in ink.

Distillation

Separation technique that involves boiling and then condensing a liquid. Used to separate liquids with different boiling points.

Fractional distillation

Distillation technique used to separate liquids with close boiling points. Uses a fractionating column.

Plum pudding model

Early model of the atom where electrons were scattered throughout a positive sphere. Proposed by J.J. Thomson.

Nuclear model

Modern model of the atom with a central nucleus containing protons and neutrons, surrounded by electrons. Proposed by Rutherford.

Alkali metals

Group 1 elements in the periodic table. Very reactive, form +1 ions.

Halogens

Group 7 elements in the periodic table. Very reactive nonmetals, form -1 ions.

Noble gases

Group 0/8 elements in the periodic table, which are very unreactive. Have a full outer electron shell.

Ionic bonding

Type of bonding where electrons are transferred between atoms. Forms ions, occurs between metals and nonmetals.

Covalent bonding

Type of bonding where electrons are shared between atoms. Forms molecules, occurs between nonmetals.

Metallic bonding

Type of bonding found in metals, involving delocalized electrons. Explains conductivity and malleability.

Polymers

Long chains of repeating units. Examples: plastics and proteins.

Monomers

The individual repeating units that make up a polymer. Example: amino acids are monomers of proteins.

Solid

State of matter with a fixed shape and volume. Particles are closely packed and vibrate in fixed positions.

Liquid

State of matter with a fixed volume but no fixed shape. Particles are close together but can move around.

Gas

State of matter with no fixed shape or volume. Particles are far apart and move randomly.

Melting

The change of state from solid to liquid. Occurs at the melting point.

Freezing

The change of state from liquid to solid. Occurs at the freezing point.

Boiling/Evaporation

The change of state from liquid to gas. Boiling occurs at the boiling point, evaporation can occur at any temperature.

Condensation

The change of state from gas to liquid. Releases energy.

Sublimation

The change of state from solid to gas. Example: dry ice.

Relative formula mass (Mr)

The mass of one mole of a substance. Calculated by adding the relative atomic masses of all the atoms in the formula.

Mole

A standard unit in chemistry that represents 6.02 x 10^23 particles. The amount of substance.

Avogadro's constant

The number of atoms in one mole of a substance: 6.02 x 10^23. Represented by N_A

Concentration

The amount of a substance in a defined space. Usually measured in moles per liter (mol/L or M).

Limiting reactant

The reactant that is completely used up first and limits the amount of product formed. Determines the yield of the reaction.

Acid

A substance that forms a solution with a pH less than 7. Donates protons (H+).

Alkali

A substance that forms a solution with a pH greater than 7. A soluble base.

Base

A substance that reacts with an acid to form a salt. Accepts protons (H+).

Reactivity series

Scale showing the relative reactivity of different metals. Used to predict displacement reactions.

Redox reactions

Reactions involving the transfer of electrons. Combination of reduction and oxidation.

Oxidation

The loss of electrons. OIL - Oxidation Is Loss.

Reduction

The gain of electrons. RIG - Reduction Is Gain.

Electrolysis

Using electricity to split up compounds. Used to extract metals or produce gases.

Exothermic reaction

Reaction where energy is released to the surroundings. Increases the temperature of the surroundings. \Delta H < 0

Endothermic reaction

Reaction where energy is absorbed from the surroundings. Decreases the temperature of the surroundings. \Delta H > 0

Reaction profile

Visual representation of the energy changes during a reaction. Shows activation energy and enthalpy change.

Activation energy

The minimum energy required for a reaction to start. Energy needed to break bonds in reactants.

Ion

A charged atom or molecule. Formed by the loss or gain of electrons.

Filtration

Separation of a liquid from an undissolved solid. Uses a filter to trap the solid particles.

Distillation

A method of separating substances based on their boiling points. Used to purify liquids.

Noble Gases

Group of elements with very low reactivity. Have a full outer electron shell, making them stable.

Covalent Bond

Joining of atoms by sharing electrons. Strong bonds, typically form between two nonmetal atoms.

Polymer

Material made up of many repeating units. Large molecules with high molecular weight.

Base

Substance that neutralizes acids. Many bases are metal oxides or hydroxides.

Reactivity Series

Series of metals ranked by reactivity. Potassium is the most reactive, gold is the least.

Electrolysis

Process of using electricity to break down a compound. Requires an electrolyte and electrodes.

Exothermic

Reaction that releases heat. The products have less energy than the reactants.

Endothermic

Reaction that absorbs heat. The products have more energy than the reactants.

Activation Energy

Energy needed to start a reaction. Represented as E_a on a reaction profile.

Proton

Positively charged particle in the nucleus. Contributes to the mass of the atom.

Neutron

Particle with no charge in the nucleus. Also contributes to the mass of the atom.

Electron

Negatively charged particle orbiting the nucleus. Determines the chemical properties of the atom.

Atomic Number

Number of protons in an atom. Defines the identity of an element.

Mass Number

Sum of protons and neutrons in an atom. A whole number.

Isotopes

Atoms of the same element with different neutron numbers. Have the same atomic number, different mass numbers.

Compounds

Substances chemically combined. Consist of two or more different elements bonded together.

Mixtures

Substances physically combined. Can be separated by physical means.

Crystallization

Formation of solid crystals from a solution. Achieved by evaporating the solvent.

Chromatography

Separation based on different adsorption. Substances move at different rates on the stationary phase.

Alkali Metals

Elements in Group 1, very reactive. React with water to form hydrogen gas and metal hydroxides.

Halogens

Elements in Group 7, reactive non-metals. Exist as diatomic molecules (e.g., Cl2, Br2).

Ionic Bonding

Bonding through electron transfer. Creates ions with opposite charges that attract each other.

Relative Formula Mass

Relative mass of a molecule. Sum of the relative atomic masses of the atoms in the formula.

Avogadro's Constant

6.02 x 10^23 particles. The number of particles in one mole of a substance.

Limiting Reactant

Reactant that limits the product amount. The reactant that is completely consumed in a reaction.

Acid

pH less than 7. Turns litmus paper red.

Alkali

pH greater than 7. Turns litmus paper blue.

Oxidation

Electron loss. Increase in oxidation number.

Reduction

Electron gain. Decrease in oxidation number.

Reaction Profile

Model of energy change in reaction. Shows the energy of reactants, products, and the transition state.

Proton

Positive particle in atoms nucleus. Has a charge of +1.

Neutron

Neutral particle in atoms nucleus. Has a mass of approximately 1 atomic mass unit (amu).

Electron

Negative particle orbiting nucleus. Has a charge of -1.

Atomic No

Unique number for each element. Number of protons in the nucleus.

Mass No

Protons plus Neutrons in nucleus. Determines the mass of an atom.

Isotope

Varied neutron count with fixed proton count. Affects the stability of the nucleus.

Compound

Chemical union of two or more elements. Held together by chemical bonds.

Mixture

Physical combination, easily separable. Components retain their individual properties.

Crystallisation

Concentrated solution forms solid crystals. A purification technique for solids.

Filtration

Separating solids from liquids. Uses a filter medium to separate the components.

Chromatography

Mix moves and separates by attraction differences. Used to separate complex mixtures.

Distillation

Evaporation plus cooled re-liquefaction. Separates liquids based on boiling points.

Alkali metals

Group 1, highly reactive. Form alkaline solutions when reacted with water.

Halogens

Always diatomic gasses found in Group 7. React with metals to form salts.

Noble gases

Gases with complete outer shells. Inert and rarely form compounds.

Covalent bond

Electrons shared not transferred. Forms molecules with specific shapes.

Polymer

A very long molecular chain. Made up of repeating monomer units.

Monomers

Molecules forming much longer structure. Link together through polymerization.