Paper 1

• What is conserved in a chemical reaction?

  Total mass of all substances
• Why must we balance chemical equations?

  Atoms that go in must come out
• What do we add up to find the relative formula mass of a compound?

  Individual relative atomic masses
• How do you calculate the relative formula mass of CO2?

  12 plus 2 times 16
• What happens when a gas product leaves the reaction vessel?

  It results in a decrease in mass
• What is a mole in chemistry?

  A specific number of atoms or molecules
• Why don't foundation students need to deal in moles?

  They can work with grams directly
• How many grams of carbon correspond to one mole?

  12 grams
• How do you calculate the number of moles from grams?

  moles equals grams over Rams
• What does the stoichiometry of a reaction indicate?

  The ratio of moles of substances
• How many moles of water are produced from 4 moles of methane?

  8 moles of water
• How do you convert moles back to mass?

  Mass equals moles times Rams
• If you have 64 grams of methane, how many moles do you have?

  4 moles of methane
• What is the limiting reactant in a reaction?

  The reactant that runs out first
• How is concentration of solutions often expressed?

  In grams per decimetre cubed
• What does a concentration of 1 mole per decimetre cubed indicate?

  One mole of solute in one decimetre cubed of solution
• What does percentage yield compare?

  Actual product made to theoretical product
• How do you calculate percentage yield?

  Actual mass divided by theoretical mass times 100
• What does atom economy measure?

  Efficiency of mass in a reaction
• How do you calculate atom economy?

  RAM of desired product over total RAM of reactants times 100
• What is the volume occupied by one mole of any gas at RTP?

  24 decimetres cubed
• What does RTP stand for?

  Room temperature and pressure
• How do you convert moles to volume at RTP?

  Multiply or divide by 24
• What topics are covered in GCSE chemistry paper 1?

  Atoms, bonding, constitutive chemistry, chemical changes
• Why is GCSE chemistry paper 1 considered difficult?

  It requires knowledge of many concepts and tricky math
• What is the best way to prepare for GCSE science?

  Practice answering exam questions
• What is an atom?

  An atom cannot be broken down by chemical means
• What is a compound?

  Two or more types of atoms chemically bonded
• How does a mixture differ from a compound?

  A mixture has components not chemically bonded
• What are the methods to separate mixtures?

  • Chromatography
  • Filtration
  • Distillation
• How does chromatography work?

  It separates substances based on their movement on paper
• What does the RF value represent in chromatography?

  Retention factor of a solute in chromatography
• What is the process of filtration used for?

  To remove insoluble particles from a liquid
• How do you separate salt from saltwater?

  Use distillation to evaporate and condense water
• What is the structure of an atom?

  It has a nucleus with protons and neutrons
• What charges do protons, electrons, and neutrons have?

  Protons +1, electrons -1, neutrons neutral
• Why must atoms have equal numbers of protons and electrons?

  To maintain a neutral overall charge
• What happens when an atom loses electrons?

  It becomes a positive ion
• What is the periodic table's group number indicative of?

  Number of electrons in the outer shell
• What are alkali metals known for?

  They react more as you go down the group