Chemistry definitions

• What’s meant by the term atomic number?

  The number of protons
• What’s a covalent bond?

  A strong force of attraction between atoms, it holds them together
• What’s an ionic compound?

  A compound that contains ions.Usually formed by a reaction between a metal and a non metal
• What is covalent bonding

  When an atom shares electron/s with another atom. Only occurs in non metals
• What is ionic bonding?

  when an atom losses or gains an electron/s
• What’s a pure substance?

  A single element or compound not mixed with any other substance. An element is a pure substance found on the periodic table.
• What’s a compound?

  Two or more elements chemically joined which are difficult to separate.
• What’s a formulation?

  A formulation is a specific combination of ingredients in a product.
• What’s an alloy?

  A mixture of 2 or more elements at least one has to be a metal.
• What’s a solute?

  Substance that dissolves in a solvent
• What’s a solvent?

  liquid which solute dissolved in
• What’s a miscible liquid?

  Liquids which can mix together eg alcohol and water
• What’s an immiscible liquid?

  liquids which cannot mix together eg oil and water
• What’s residue?

  The insoluble substance left on filter paper
• What’s the filtrate?

  The liquid that flows through the filter paper
• What’s the distillate?

  The pure liquid that is collected during distillation
• What’s an intermolecular force/van Dee vaals forces?

  A weak force holding the molecules together
• What’s a strong acid?

  An acid that completely ionises in water.(they break up completely into their ions so there is a high conc of H+ ions in solution)
• What’s a weak acid?

  An acid that only partially ionises.(only a small fraction of the molecules break into ions when added to water)
• What’s a strong alkali?

  An alkali that completely ionises.(break up completely to form their ions)
• What’s a weak alkali?

  An alkali that only partially ionises.(don’t completely break up into their ions fully)
• dilute and conc acids

  Conc acids contain a large number of acid particles dissolved per unit volume.Dilute contains a small number.
• Corrosive

  Burns and destroys living tissue eg conc acid
• Explosive

  Explodes of exposed to flames,heated or knocked eg potassium
• Flammable

  Catches fire easily when in contact with air eg ethanol
• Toxic

  Can kill by poisoning eg weed killer,cyanide
• Moderate hazard

  May be harmful or an irritant eg dilute sodium hydroxide
• A period is the number of shells
• A group is the number of electrons in outer shell
• What does the term mass number mean?

  The sum of protons and nuetrons in an atom
• What’s an allotrope?

  When an element can be in the same physical but different forms
• What does diatomic mean?

  When an atom naturally has 2 atoms eg Cl2, I2, O2
• What’s an isotope?

  Atoms of an element that have same amount of protons and electrons but different number of neutrons.
• What’s a salt?

  A compound formed when some or all of the hydrogen ions in an acid are replaced by metal ions or ammonium ions.
• Ductile


  Drawn into wires
• Malleable

  Can be hammered into sheets without breaking.
• Soner

  Hit it, makes sound
• Aqueous

  A solution in which the solvent is water
• what’s an exothermic reaction?

  Release of heat (Gives out energy)