HYDROGEN, OXYGEN, THE ATMOSPHERE, POLLUTION Flashcards
what is the word equation for metal + water (steam- for unreactive metals)
metal + water -> metal oxide + hydrogen
what is the word equation for metal + water with ( K, Na, Ca )
metal + water -> metal hydroxide + hydrogen
describe the observations with potassium + water
- it floats and fizzes
- moves around on the surface of the water
- melts into a silver ball
- it catches fire and burns with a lilac flame
- it eventually gets smaller and disapears
- it is a very violent reaction
- when universal indicator is added, the solution turns blue/black indicating that a string alkali has been produced.
what is the equation (word and chemical) for potassium + water
potassium (s) + water (l) -> potassium hydroxide (aq) + hydrogen (g)
K + H2O -> KOH + 1/2H2
is potassium + water a useful method for preparing hydrogen
no, because the reaction was too violent and hard to contain
describe the observations for sodium and cold water
- it floats
- it moves around on the surface of the water
- it fizzes
- melts into a silvery ball
what is the word and chemical equation for sodium and water
sodium (s) + water (l) -> sodium hydroxide (aq) + hydrogen(g)
2Na + 2H2O -> 2NaOH + H2
is sodium and water a useful method for preparing hydrogen
no, the metal is too reactive (not as violent as K)
how can you prepare hydrogen
it can be prepared by reacting water or steam with a metal
describe the observations for calcium and cold water
- the calcium sinks and effervesces (bubbles and fizzes)
- it fizzes and gas bubles are produced and the gas is collected at the top of the test tube.
- the calcium bobs up and down
- a white suspension of calcium hydroxide is seen and the water gets warm
- it is a good way of collecting hydrogen
what is the word and chemical equation for calcium and water
calcium (s) + water (l) -> calcium hydroxide(aq) + hydrogen(g)
Ca + 2H2O -> Ca(OH)2 + H2
describe the observations for magnesium and steam
- the magnesium burns with a bright white light
- a white ash (solid) remains (MgO)
- a colourless gas is collected
describe the observations for magnesium and cold water
the magnesium sinks, it is a very slow reaction and would take a week to collect half a test tube of hydrogen
what is the word and chemical equation for magnesium and water (g)
magnesium + water (g) -> magnesium oxide + hydrogen
Mg (s) + H2O(g) -> MgO + H2(g)
describe how aluminium reacts with water
aluminium cannot react with hot or cold water
aluminium foil does not react with steam - it has an oxide layer of the surface however, if this layer is removed it will then react
powdered aluminium reacts with steam when heated to red heat
what is the word and chemical equation for aluminium and steam
aluminium + steam -> aluminium oxide + hydrogen
2Al(s) + 3H2O(g) -> AlO3 + 3H2(g)
describe how zinc reacts with water
zinc cannot react with react with hot or cold water
zinc can react when it’s heated with steam
what is the word and chemical equation for since and steam
Zinc(s) + water (g) -> zinc oxide(s) + hydrogen(g)
Zn + H2O -> ZnO + H2
describe the appearance of zinc oxide when it has reacted with steam
it is a yellow coal
describe how iron reacts
iron rusts slowly in the prescence of air and water
it reacts reversible with steam at red heat
what is the word and chemical equation for iron and steam
Iron + water (g) -> iron oxide + hydrogen
3Fe (s) + 4H2O (g) -> FeO4(s) + 4H2(g)
describe the appearance of iron oxide when it has reacted iron with steam
it is a black powder
describe how copper reacts with water and steam
copper does not- it is below hydrogen in the reactivity series so cannot displace the hydrogen from water
(metal + water is a displacement reaction)
when creating hydrogen with a metal describe what must happen for the reaction to work
the reaction is a displacement reaction so the metal must be above hydrogen in the reactivity series for the reaction to work - metal + acid is usually a lot more violent than metal + water
there is also anhydrous copper sulphate which is the catalyst and speeds up the reaction
describe the word equation for metal + acid
metal + acid -> salt + hydrogen
describe salts
an acid in which the hydrogen has been replaced by a metal
metal + sulfuric acid -> ?
metal sulfate + hydrogen
metal + hydrochloric acid -> ?
metal chloride + hydrogen
metal + nitric acid -> ?
metal nitrate + hydrogen
what is a substance which speeds up a reaction but remains chemically unchanged?
a catalyst
what is the word and chemical equation for zinc and sulfuric acid
zinc + sulfuric acid -> zinc sulfate + hydrogen
Zn (s) + H2SO4 (aq) -> ZnSO4 (aq) + H2 (g)
describe the observations of potassium and sodium + acid
you don’t - it’s too violent
(both potassium and sodium are very reactive more so than hydrogen)
(both potassium chloride and sodium chloride are soluble)
describe what happens with calcium + hydrochloric acid for making hydrogen
calcium is more reactive than hydrogen
calcium chloride is soluble
it’s very violent but not a dangerous as K and Na
describe what happens with calcium + sulfuric acid
calcium sulfate is insoluble (CaSO4 insoluble)
calcium is more reactive than hydrogen
reaction is very slow (doesn’t really happen at all
describe what happens with copper plus acid to make hydrogen
copper is below hydrogen so won’t react (the salt is insoluble)