Chemistry exam

• What does air hole open look like?

  Blue flame, loud, hotter
• What does air hole closed look like?

  Orange, silent, sooty, less hot
• What are properties of gas?


  Spread out particles, moves fast, random directions, no fixed shape.
• What are properties of liquid?


  particles have no gaps, random directions, rolling over each other, no fixed shape.
• What are properties of solids


  Particles in neat rows, no gaps, vibrating, fixed shape
• What are the standard safety rules in a lab


  Don’t run in a lab, don’t sit down, don‘t bring food or water, wear a lab coat and safety goggles during an experiment and have hair tied up.
• What is the change of state from solid to liquid?

  Melting, gains energy
• What is the change of state from liquid to solid?

  Freezing, loses energy
• What is the change of state from liquid to gas?

  Boiling/Evaporating, gains energy.
• What is the change of state from gas to liquid?

  Condensation, loses energy
• What is the change of state from solid to gas?

  Subliming, gains energy
• What is the change of state from gas to solid?

  Subliming, loses energy.
• Why is there a period of constant temperature on a cooling/heating curve during a change of state?

  All the heat energy is being used to break or form bonds between the particles.
• What is the difference between chemical and physical changes?

  Chemical reactions are irreversible but Physical changes are reversible.
• What are some signs of a chemical reaction?

  Colour change, Effervescence (gas is produced), Endothermic (temperature drops), Exothermic (temperature rises), Precipitate (solid forms when 2 solutions are mixed), Precipitation reaction (2 solutions are mixed and an insoluble product is formed).
• What does the periodic table list?

  All known elements, with metals on the left-hand side and non-metals on the right.
• What is an element?


  An element is a substance which is made of only one type of atom.
• What is a compound?


  A compound is a substance composed of two or more elements chemically bonded together.
• What is the difference between an atom and a molecule

  An atom is the smallest/simplest particle of an element (the building blocks of everything) while a molecule is a particle made of 2 or more atoms that are chemically bonded. They are found in compounds.
• What is a mixture?

  A mixture is a substance made up of two or more different substances that are not chemically bonded.
• What are some ways that mixtures can be separated?

  Filtration, distillation, chromatography, evaporation.
• The vertical columns in a periodic table are called

  Groups
• The horizontal rows in the periodic table are called

  Periods
• How does filtration work?

  Filtration works by separating an insoluble solid from a liquid. It catches the solid in filter paper. The solid is the residue. It catches the liquid in a conical flask. The liquid is the filtrate. To set up, put a filter funnel in a conical flask then put filter paper in the filter funnel.
• How does evaporation work?

  We use evaporation to separate a soluble solid from a liquid. Using an evaporating basin, gauze, a tripod, Bunsen and heatproof mat, we heat up the solution until all the liquid has evaporated, leaving just the solid.
• How does distillation work?

  Distillation works by separating a soluble solid from a liquid, or a solvent from a mixture of 2 solvents with different boiling points. A burner is used to heat up the solution until the solvent starts to evaporate. The gas is trapped and goes through a pipe with cold water running through it, called a Liebig condenser. This condenses the vapour and leaves the distillate to flow into a beaker. There is a thermometer at the top to see when the liquid will start to boil.
• How does chromatography work?

  It is used to separate colours or dyes. You draw a line in pencil and carefully add the dyes to the chromatography paper. You suspend the chromatogram over a beaker in solvent (below pencil line) and allow the solvent to rise up the paper. The dyes separate due to their affinity to the solvent and paper. The more soluble dyes travel further up the paper. You use it to see how many dyes a dye is made from.
• What is the formula for hydrochloric acid?

  HCl
• What is the formula for sulphuric acid?

  H2SO4
• What is the formula for Nitric Acid?

  HNO3
• What is the formula for sodium hydroxide?

  NaOH
• What is the formula for potassium hydroxide?

  KOH
• What is the formula for calcium hydroxide?

  Ca(OH)2
• What is the formula for lithium hydroxide?

  LiOH
• What is the formula for barium hydroxide?

  Ba(OH)2
• What is the pH scale universal indicator colour for a strong acid?

  Red
• What is the pH scale universal indicator colour for a weak acid?

  Yellow
• What is the pH scale universal indicator colour for a neutral substance?

  Green
• What is the pH scale universal indicator colour for a weak alkali?

  Blue/turquoise
• What is the pH scale universal indicator colour for a strong alkali?

  Purple