2 Inorganic Chemistry Flashcards
what happens when lithium reacts with water
relatively slow reaction
lithium doesn’t melt
effervescence can be observed
what happens when sodium reacts with water
sodium melts into a ball as large amounts of heat energy is released
hydrogen released catches fire and causes the Na to dash around the surface of water
what happens when potassium reacts with water
creates a lilac flame
melts into a shiny ball which dashes across the surface of the water
what are the group 1 metals called
alkali metals
what happens to the reactivity as you go down group one
increases because as we go down the group each element has one more outer shell meaning the distance between the outer most shell and the nucleus increases. this decreases the electrostatic force of attraction meaning its easier to lose the one electron as less energy is required
group one elements only need to lose one electron to form a complete outer shell
trends in the group one / alkali metals
increase in reactivity as we go down the group because the number of electron shells increase
all soft and easy to cut and get softer as we move down the group
low melting points which decrease as we go down the group
how do the alkali metals react with oxygen
when the alkali metals react with oxygen they form metal oxides
this causes a dull coating on the metals
this happens quicker as we go down the group
alkali metal + oxygen -> metal oxide
how do the alkali metals react with water
reactivity increases as you go down the group
general reaction formula:
alkali metal + water -> metal hydroxide + hydrogen
The hydroxides formed all have the same general formula and are colourless, aqueous solutions
predicting properties in group 1
reactivity increases as we go down the group
melting point decreases as we go down the group
get softer as we go down the group
the density increases as we go down the group
colour and physical state (at room temp) of fluorine
yellow gas
colour and physical state (at room temp) of chlorine
pale yellow/green gas
colour and physical state (at room temp) of bromine
red/brown liquid
colour and physical state (at room temp) of iodine
grey solid
colour and physical state (at room temp) of astatine
black solid
trend in properties of the halogens
melting and boiling points increase as you go down the group because the atoms become larger and therefore the intermolecular forces get stronger
the colours of the halogens get darker in colour as you go down the group
halogens decrease in reactivity as you go down the group
the rate of reaction is slower as you go down the group
what is a metal halide
when a halogen reacts with a metal they form ionic compounds which are metal halide salts
what is a halide
a halogen ion
what is a displacement reaction
where a more reactive halogon is added to a salt (another halogen thats reacted to a metal) and the more reactive halogen displaces the less reactive halogen from the salt
Cl2(aq) + 2KI(aq) → 2KCl(aq) + I2(aq)
here chlorine displaces iodine showing how chlorine is more reactive
why does the reactivity decrease when you go down the halogen group
as you go down the group the amount mass of the halogens increase and so does the number of electron shells
halogens form negative ions (they gain an electron)
the distance from the nuclei (positive) to the outer shell increases which means there is a smaller force of attraction so it is harder to gain an electron
what % of nitrogen is there in the air
78%
what % of oxygen is there in the air
21%
what % of argon is there in the air
0.9%
what % of CO2 is there in the air
0.04%
how to determine the percentage by volume of oxygen in air using experiments involving the reactions of metals (e.g. iron) with air
- place an excess of wet iron filings into a conical flask (100cm3) full of air
- place a bung on the top of the conical flask connected to a syringe
over time the iron will rust (react with oxygen) until all of the oxygen is used up. this will move the syringe reading from 100 to 79ish showing oxygen makes up 21% of the air
how to determine the percentage by volume of oxygen in air using experiments involving the reactions of non-metals (e.g. phosphorus) with air
- place a small amount of phosphorus onto a evaporating dish in a bell jar which is sitting in a trough of water
- set the phosphorus on fire
As the phosphorus burns it uses up the oxygen inside the bell jar and the water level rises
By making careful measurements of water levels before and after the experiment you can determine the percentage of oxygen in the air
combustion of magnesium in oxygen
intense white flame
white powder produced
combustion of hydrogen in oxygen
exothermic
water is produced
combustion of sulpher in oxygen
blue flame
colourless, poisonous gas produced
what is thermal decomposition
a reaction where a substance breaks down due to the action of heat
what is the formation of carbon dioxide from the thermal decomposition of metal carbonates
metal carbonate → metal oxide + carbon dioxide
what is the happens when copper(II) carbonate is thermally decomposed
copper(II) carbonate → copper(II) oxide + carbon dioxide
green -> black
what happens if we increase the amount of CO2 in the atmosphere
contribute to the enhanced greenhouse effect and climate change
what type of gas is CO2
a greenhouse gas
practical: determine the approximate percentage by volume of oxygen in air using a metal or a non-metal
- place an excess of wet iron filings into a conical flask (100cm3) full of air
- place a bung on the top of the conical flask connected to a syringe
over time the iron will rust (react with oxygen) until all of the oxygen is used up. this will move the syringe reading from 100 to 79ish showing oxygen makes up 21% of the air
what is the order of the reactivity series
potassium, sodium, lithium, calcium, magnesium, aluminium, carbon, zinc, iron, lead, hydrogen, copper, silver, gold
how can metals be arranged into a reactivity series based on their reaction with water
whichever reacts most violently with water is the most reactive
for example potassium is the most reactive with water because it is the top of the reactivity series
metal + water ⟶ metal hydroxide + hydrogen
how can metals be arranged into a reactivity series based on their reaction with dilute acids
whichever reacts most violently with dilute acid is the most reactive
for example potassium is the most reactive with dilute acid because it is the top of the reactivity series
only elements more reactive than copper will react with acid
metal + acid ⟶ salt + hydrogen
how can metals be arranged in a reactivity series based on their displacement reactions between metal and metal oxides
a more reactive metal will displace a less reactive metal from a compound
to do this in metal oxides you can heat it
for example more reactive zinc will displace less reactive copper
zinc + copper(II) oxide → zinc oxide + copper
we can repeat this reaction with different metals to determine which is more / less reactive
so potassium will displace everything as it as the most reactive metal
how does displacement work with the reactivity series
a more reactive metal will displace a less reactive metal from a compound
how can metals be arranged in a reactivity series based on their displacement reactions between metal and aqueous solutions of metal salts
a more reactive metal will displace a less reactive metal from a compound so
This is easily seen as the more reactive metal slowly disappears from the solution, displacing the less reactive metal
For example, magnesium is a reactive metal and can displace copper from copper(II)sulfate solution:
Mg + CuSO4→ MgSO4 + Cu
The blue colour of the CuSO4 solution fades as colourless magnesium sulfate solution is formed
Copper coats the surface of the magnesium and also forms solid metal which falls to the bottom of the beaker
what conditions does iron need to rust
water and oxygen
what is rust
hydrated iron oxide
how to stop iron rusting
barrier methods
galvanising
sacrificial protection.
what is the barrier method to stop iron rusting
the barrier such as paint or oil stop the oxygen reaching the iron and therefore stopping rusting
what is galvanising to stop iron rusting
by coating the iron in a more reactive metal (such as zinc) means that more reactive metal will react with oxygen and water instead of iron stopping it from rusting
If the coating is damaged or scratched, the iron is still protected from rusting because more reactive preferentially corrodes as it is higher up the reactivity series than iron
The iron stays protected as it accepts the electrons released by more reactive metal, remaining in the reduced state and thus it does not undergo oxidation
what is OILRIG
oxidation is loss of electrons
reduction is gain of electrons
what is oxidation
Oxidation is any reaction in which a substance gains oxygen
oxidation is loss of electrons