Chemistry paper 1

• independant variable: what you change or select

  dependant variable: what you measure

  control variable: what you keep the same
• what word describes how noble gases exist as single molecules?

  monatomic
• what word describes how halogens exist as pairs?

  diatomic
• if the metal is more reactive than hydrogen in electrolysis, what will form at the cathode?

  hydrogen
• what forms at the anode if there is no halide present or the solution is dilute?

  oxygen
• does the cathode give or take electrons?

  gives
• does the anode give or take electrons?

  takes
• what elements form at the cathode?

  metal or hydrogen
• what element forms at anode?

  a non-metal or oxygen
• what do you mix with aluminium oxide to lower its melting point?

  cryolite