d) reactivity series IMPROVED USING CGP

what metals react with water

Potassium, sodium, lithium and calcium

what metals barely react with water/ react with steam

magnesium, aluminium, zinc, iron

what metals dont react with water or steam

metals below hydrogen

what metals react vigorously with dilute acids

potassium, sodium, lithium

what metals react with dilute acids

calcium, magnesium, aluminium, zinc, iron

what metals don't react with dilute acids

metals below hydrogen

acid + metal

acid + metal -> salt + hydrogen

practical: investigating reactions between dilute HCl and H2SO4 acids and metals

- 3 boiling tubes with equal volumes of HCl or H2SO4

- place Mg, Zn, Fe pieces in test tube (each piece same size + shape)

- measure the rate at which hydrogen bubbles given off

- confirm the hydrogen with squeaky pop test

practical - which metal should give loudest squeaky pop

magnesium bc it has the most vigorous reaction, producing the most H2 gas

does Mg react with cold or warm dilute acids

reacts vigorously with cold dilute acids + produces lots of bubbles

does Fe and Zn react with dilute acids

- react slowly

- reacts stronger if heated

more reactive metal + water ->

metal hydroxide + hydrogen

less reactive metal + steam ->

metal oxide + hydrogen

as the reactivity of the metal increases, the amount of energy given out by the reaction ...

increases

lithium + water observations

- floats

- fizzes

- gets smaller

- disappears

sodium + water observations

- melts to form ball

- moves around on surface

- fizzes

- disappears

potassium + water observations

- melts

- floats

- moves around quickly

- hydrogen gas ignites + lilac flame

reactivity series

K

Na

Li

Ca

Mg

Al

Carbon

Zn

Fe

Hydrogen

Cu

Ag

Au

displacement reactions

when a more reactive metal pushes out a less reactive metal from a compound

what is a non-visual observation of a displacement reaction

- temp change

- a more reactive metal will give a greater temp change than a less reactive one

what is rusting

the corrosion of iron

what is corrosion

when a metal becomes degraded due to oxidation (usually from oxygen in the air)

what are the conditions for rusting

when the iron is in contact with both:

- oxygen (from air)

- and water

what type of reaction is the corrosion of iron

oxidation reaction

describe what happens during rusting (in terms of oxidation and bonding)

- iron gains oxygen to form iron(III)oxide

- water then becomes loosely bonded to the iron(III) oxide

- this forms hydrated iron(III)oxide

word equation for rusting

iron + oxygen + water -> hydrated iron (III) oxide (rust)

why does rusting happen continually

- because it is a soft crumbly solid it flakes off

- and more iron is available to rust again

what are the 2 main ways of preventing rusting

- barrier methods

- sacrificial protection

what are 2 barrier methods

- painting/ coating with plastic - can be decorative

- oiling/ greasing - used when moving parts involved

what is the sacrificial method

- placing a more reactive metal with the iron

- the water and oxygen react with the sacrificial metal instead

what metal is often used as a sacrificial metal

zinc

what is galvanising

spraying a coating of zinc onto the object

what is an alternative method of sacrificial protection using zinc

- bolting big blocks of zinc to the iron

- this is used on ships' hulls, or on underground iron pipes

OILRIG

oxidation is loss (of electrons) reduction is gain (of electrons)

oxidising agent

substance that oxidises the metal (and is reduced)

reduction agent

substance that reduces the metal (and is oxidised)

redox reaction

reaction where both oxidation and reduction occur

oxidation

- loss of electrons

- gain of oxygen

reduction

- gain of electrons

- loss of oxygen