Inorganic Chemistry Flashcards
What observations are made when alkali metals react with water
-lithium, sodium and potassium react vigorously in water
-reaction of the alkali metals with water produced hydrogen, causing fizzing
Word equation of alkali metals (sodium) reacting with water
2Na(s) + 2H2O(l) -> 2NaOH(aq) +H2(g)
How do alkali metals react with the air
They react with the oxygen to form metal oxides
What does each alkali metal form when reacted with oxygen
-lithium forms Li2O
-sodium reacts to form Na2O and Na2O2
-potassium reacts to form K2O2 and KO2
Why do group 1 elements become more reactive down the groups
-they have 1 electron in their outer shell
-further down group 1, the outermost electron is in a shell that is further from the nucleus
-attraction between outermost electron and nucleus becomes less
-as atoms get bigger when you go down group 1 elements, they become more reactive
How do properties of group 7 elements change as you go down the group
-elements become darker and have a higher boiling point
-this is because the intermolecular forces are greater when the size of the atoms increase
Colour, state of chlorine
Green, gas
Colour and state of bromine
Red-brown, gas
Colour and state of iodine
Dark grey, solid
Why does the reactivity of halogens decrease as you go down the group
-group 7 elements have 7 electrons in their outer shell, they can gain one electron to form an ion
-it is harder to attract the extra electron as you go down the group, as the outer shell if further away from the nucleus, as the attraction between the outer shell electron and the nucleus decreases when the atom is larger
What is a displacement reaction
When a more reactive element pushes out a less reactive element from a compound
Name of the loss of electron and gain in electrons
Loss of electrons:oxidation
Gain in electrons:reduction
What do oxidising agents and reducing agents do
Oxidising agents accept electrons and gets reduced
Reducing agents donates electrons and gets oxidised
What is it called when a reduction and oxidation happens at the same time
Redox reaction
Earth’s gas proportion
78% nitrogen
21% oxygen
0.04% carbon dioxide
1% argon(nearly)
Practical to investigate the proportion of oxygen in the atmosphere
-soak iron wool in acetic acid
-push the wool into a measuring cylinder and invert it into a beaker of water
-record the starting position of the water using the scale
-over time, the level of the weather in the measuring cylinder will rise, as iron reacts with the oxygen to make iron oxide
-water rises to fill up the space the oxygen took up
-leave measuring cylinder for a week or nail the water level stops changing
-record finishing position of the water
((Start volume - final volume)/start volume) x 100
Experiment to investigate the proportion of oxygen in air using phosphorus
-placate phosphorus in a tube and attach a glass syringe at either end
-make sure on syringe is filled with air and the other is empty
-heat the phosphorus and use the syringes to pass air over it, the phosphorus will react with oxygen in the air to make phosphorus oxide
-as it reacts, the amount of air in the syringes will decrease
-measure the starting and final volumes of air using the scale on one of the syringes
-calculate the percentage of oxygen in the air
What happens when magnesium is burnt to react with oxygen
-magnesium burns with a bright white flame in air and the white powder that is formed in magnesium oxide
-magnesium oxide is slightly alkaline when it’s dissolved in water
2Mg + O2 -> 2MgO
What happens when hydrogen is burnt to react with oxygen
-Hydrogen burns easily in oxygen, can be explosive
-orange/yellow flame and the only product is water
2H2 + O2 -> 2H2O
What happens when sulfur is burned to react with oxygen in the air
-sulfur burns in air or oxygen with a pale blue flame and produced sulfur dioxide
-sulfur dioxide s acidic when it’s dissolved in water
S + O2 -> SO2
