papers Flashcards
how are the elements arranged in the periodic table
by increasing number of protons
what observations are made when group 1 metals react with water
- moves on surface of water
- substance gets smaller/disappears
how does a catalyst increase rate of reaction
- by providing an alternate pathway
- with lower activation energy
why do we use a fume cupboard when working with chlorine
because chlorine is TOXIC/POIOSNOUS
what does a double arrow in an equation mean
the reaction is reversible
what state symbol goes with H20
liquid
possible safety precautions
- goggles
- lab coat
- safety screen
- position class further away
- do in fume cupboard
in the reaction between ammonia solution and sulfuric acid how does the sulfuric acid act in this reaction
as a proton donor
because it gives away its H (H+) which is essentially a proton
explain why the chemical formula of ammonium sulfate is (NH4)2SO4
- because the charge of ammonium in +
- and the charge of a sulfate ion is 2+
- so two ammonium ions are used for one sulfate SO CHARGES BALANCE EACH OTHER
what would the displayed formula of polypropene look like
what type of reaction is it when a substance is HEATED on its own
decomposition
why does it take several minutes for the ammonium chloride to form in the reaction between hydrochloric acid and ammonia solution
- gas particles move in random directions
- and collide with other particles in the air
- and collide with the sides of the test tube
which slows them down
Explain the shape of the graph
- the reaction is exothermic so the temperature rises
- after 25cm3 the reaction is complete
- so no more heat is given out even as you add more sodium hydroxide
describe a way of making solid calcium chloride conduct electricity
- by heating it
- until molten
Explain what the chromatogram shows about the composition of the green food colouring
- contains three dyes
- contains dyes B and D
- because it has dots at the same level as B and D
