NCEA L1 ChemBio flashcards
NCEA L1 ChemBio · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Atomic number
- The number of protons in the nucleus of an atom. It identifies the element and, in a neutral atom, equals the number of electrons.
- Mass number
- The total number of protons and neutrons in an atom's nucleus. Isotopes of an element have the same mass number only if neutron counts match.
- Isotope
- An atom of the same element with the same number of protons but a different number of neutrons. Isotopes have identical chemical properties but different masses.
- Ionic bond
- The electrostatic attraction between a positively charged metal ion and a negatively charged non-metal ion, formed when electrons are transferred from one atom to another.
- Covalent bond
- A bond formed when two atoms share one or more pairs of electrons. Single bonds share one pair; double bonds share two pairs.
- Ion
- A charged particle formed when an atom gains or loses electrons. Gaining electrons gives a negative ion; losing electrons gives a positive ion.
- Mole
- The amount of substance containing 6.02 x 10^23 particles. The mass of one mole in grams equals the molar mass of the substance.
- Molar mass
- The mass of one mole of a substance in grams per mole. It is calculated by adding the relative atomic masses of all atoms in the formula.
- Concentration
- The amount of solute dissolved in a given volume of solution, commonly expressed as moles per litre (mol L^-1). Calculated using c = n / V.
- pH scale
- A scale from 0 to 14 measuring hydrogen ion concentration. Values below 7 are acidic, 7 is neutral, and above 7 is basic.
- Neutralisation reaction
- A reaction between an acid and a base producing a salt and water. For example, hydrochloric acid plus sodium hydroxide gives sodium chloride and water.
- Exothermic reaction
- A chemical reaction that releases energy to the surroundings, usually as heat. The temperature of the surroundings rises during the reaction.
- Endothermic reaction
- A chemical reaction that absorbs energy from the surroundings, usually as heat. The temperature of the surroundings falls during the reaction.
- Catalyst
- A substance that increases the rate of a chemical reaction by lowering the activation energy, without being consumed in the reaction.
- Conservation of mass
- In a chemical reaction, atoms are neither created nor destroyed. The total mass of reactants equals the total mass of products.
- Balanced equation
- A chemical equation in which the number of atoms of each element is equal on both sides, reflecting conservation of mass.
- Periodic table groups
- Vertical columns of the periodic table. Elements in the same group have the same number of outer-shell electrons and similar chemical properties.
- Electron shell configuration
- The arrangement of electrons in shells around the nucleus, filled in order 2, 8, 8 for the first three shells. The outer shell determines reactivity.
- Cell theory
- The principle that all living organisms are made of one or more cells, that cells are the basic unit of life, and that cells arise from existing cells.
- Prokaryotic cell
- A cell lacking a membrane-bound nucleus and membrane-bound organelles, such as a bacterium. Its genetic material lies free in the cytoplasm.
- Eukaryotic cell
- A cell containing a membrane-bound nucleus and other membrane-bound organelles, such as plant, animal, and fungal cells.
- Mitochondrion
- An organelle that carries out aerobic respiration, releasing energy stored as ATP. Cells with high energy demands contain many mitochondria.
- Chloroplast
- A plant cell organelle containing chlorophyll that carries out photosynthesis, converting light energy into chemical energy in glucose.
- Cell membrane
- A semi-permeable barrier surrounding the cell that controls which substances enter and leave, and separates the cell from its environment.
- Photosynthesis
- The process by which plants use light energy to convert carbon dioxide and water into glucose and oxygen, occurring mainly in chloroplasts.
- Aerobic respiration
- The breakdown of glucose using oxygen to release energy as ATP, producing carbon dioxide and water as waste products.
- Enzyme
- A protein that acts as a biological catalyst, speeding up reactions. Each enzyme has an active site specific to its substrate.
- Denaturation
- The loss of an enzyme's shape and function caused by high temperature or extreme pH, which distorts the active site.
- Diffusion
- The net movement of particles from a region of higher concentration to a region of lower concentration, requiring no energy input.
- Osmosis
- The movement of water molecules across a semi-permeable membrane from a region of higher water concentration to a region of lower water concentration.
- DNA base pairing
- The rule that adenine pairs with thymine and guanine pairs with cytosine in DNA. The base sequence carries genetic information.
- Food chain energy loss
- In a food chain, only about 10% of energy passes to the next trophic level; the rest is lost as heat through respiration and waste.