Chemical Change Part One Flashcards
how does sodium react with oxygen
a bright yellow flame
reaction happened quickly
hot and explosive
how does iron react with oxygen
sparks
how does copper react with oxygen
turns black from red/brown
how does magnesium react with oxygen
bright white flame
turned into white powder
what happens when a metal reacts with oxygen
creates a metal oxide
what kind of reaction happens when a metal reacts with oxygen and why
oxidation reaction as they gain oxygen
what is the word equation for metals + oxygen
metal + oxygen —–> metal oxide
what do metals reacting with water form
a metal hydroxide and water
what is the word equation for metals + water
metal + water ——> metal hydroxide + hydrogen
what happens when lithium reacts with water
floats on water
fizzes
let off steam
what happens when sodium reacts with water
fizzed
moved fast on surface of water
sparked
how does potassium react with water
lilac flame
exploded
fizzed very quickly
sparked
what condition is the metal hydroxide
alkaline
turns universal indicator purple
what is the formula for sulfuric acid
4
H. SO
2
what is the formula for nitric acid
HNO
3
what is the word equation for metals and acid
metal + acid ——> salt + hydrogen
what is the hydrogen test
a lit splint that pops
how do you name salts
1 first word of salts name is metal in experiment
2 second word of salts name is acid
what is the reactivity series
potassium
sodium
calcium
magnesium
aluminium
carbon - non metal
zinc
iron
tin
lead
hydrogen - non metal
copper
silver
gold]
platinum
what does the reactivity series go in order of
most reactive to least reactive
what is the acronym to remember the reactivity series
please
send
charlie’s
monkeys
and
chris’s
zebras
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tall
lead
hard
cages
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guarded
promptly
how are metals displaced in the reactivity series
if a metal is above the other metal in the compound the reaction will happen
if a metal is below the other metal in a compound the reaction will not happen
what is a displacement reaction
when a more reactive metal can displace a less reactive metal from a compound
which are the more reactive metals in the reactivity series and how are they extracted
potassium
sodium
calcium
magnesium
aluminium
extracted using electrolysis
what are the less reactive metals in the reactivity series and how are they extracted
using carbon in a displacement reaction
which are the reactivity series unreactive metals and how are they extracted
silver
gold
found in natural state and don’t need to be extracted
what is the rock called when there is enough of the metal to make it work extracting
an ore
where are metals found
the ground
what is it called when a rock has metal but not enough worth extracting
just a rock
how is a metal turned from ore to metal oxide
metal oxide is separated from rock
how is metal oxide turned into a metal after being ore
the metal is chemically separated from the oxygen
why does how the metal is separated from oxygen vary
depends on where it is in the reactivity series
why is carbon used to extract less reactive metals
it is higher than the metals in the reactivity series so it is more reactive
steals the oxygen away
leaves metal by itself and makes carbon dioxide
called a displacement reaction
what is it called as each metal loses oxygen
called a reduction reaction
how are the most reactive metals extracted
electrolysis
what is electrolysis
when we split the substance using electricity
the metal oxide is separated from the oxygen
what is oxidation
when a substance gains oxygen
when a substance loses electrons
what is reduction
when a substance loses oxygen
when a substance gains electrons
where are the electrons on an oxidation half equation
always on the right
where are the electrons in a reduction reaction half equation
always on the left
what is a redox reaction
when a substance has been oxidised and a substance has been reduced at the same time
what is an indicator
a substance which changes colour to tell you if something is acid or alkali
what are indicator examples
litmus paper
universal indicators
what is the colour and numbers of strong acids
1-3
red
what is the colour and number of weak acids
4-5
orange/yellow
what are everyday examples of acids
lemon juice
vinegar
fizzy drinks
what are lab examples of acids
nitric acid
sulfuric acid
hydrochloric acid
how does acid taste
sour
what does an acid form in a solution
H+ ions
what are the number and colours of weak alkalis
8-11
dark green/blue
what are the number and colours of
strong alkali
12-14
blue/purple
what are the everyday examples of alkali
bleach
soap
toothpaste
indigestion tablets
what is a base
metal oxide or metal hydroxide that is insoluble
what is an alkali
metal hydroxide that is soluble
how do alkalis taste
bitter
what do alkalis form in a solution
OH- ion
how do you write ionic equations
re write the equation showing separate ions present in each substance
remove any spectator ions (ions that don’t change state or charge)
rewrite out the equation without the spectator ion
what does the volume have to be in for concentration
dm^3
how do you change cm^3 to dm^3
divide by 1000
what is the concentration equation
concentration = mass of solute/ volume of solvent
what units is concentration in
g/dm^3
how would a change in mass of the solute affect the concentration
if we increase the mass the concentration will increase
how would a change in volume of the solvent affect the concentration
decreasing the volume increases the concentration
how do you identify strong and weak acids (test 1)
- 2cm depth of each acid in 2 separate test tubes
- add two drops of universal indicator to each acid and record the colour observed and work out ph number
how do you identity strong and weak acids (test 2)
- 2 cm depth of each acid into separate test tubes and add a piece of magnesium ribbon to each one
- time how long it takes for the reaction to stop
what is the result of test 1 of identifying strong and weak acids
strong acid turns red
weak acid turns orange
what is the result of test 2 for strong and weak acids
strong acid would bubble more and would stop reacting first
what is test 3 for identifying strong and weak acids
- put 2cm depth of each acid into separate test tubes and add a spatula full of powdered sodium carbonate to each one
- time how long it takes for the reaction to stop
what are the results of test 3 of identifying strong and weak acids
strong acid bubbles more and stops reacting quicker
what are 3 examples of a strong acid
hydrochloric acid
sulfuric acid
nitric acid
what are 3 examples of a weak acid
ethanoic acid (vinegar)
citric acid (citrus fruits)
carbonic acid (fizzy drinks)
what do strong acids do in water
completely ionise in water (this means the ions split up)
what does strong acids completely ionising in water mean
the solution has a high concentration of H+ ions
low ph
this is not reversible
what do weak acids do in water
partially ionise in water (only a small amount of acid molecules split up )
why do weak acids partially ionise in water
have a low concentration of H+ IONS
higher pH
how do you calculate pH
-log. [H+]
10
how do you calculate [H+]
[H+] = 10^-PH
what is a concordant result
two titres that are within 0.1cm^3 of eachother
titration calculation steps
write known and unknown
moles= conc x volume/ 100
work out ratio
workout unknown concentration
convert mol/dm^3 to g/dm^3 = CONCENTRATION G/DM3 = concentration in mol/dm3 x mr of substance
