Chemistry of the elements Flashcards
How do Group 1 elements react with water
It is used to decipher if an element is part of this family
Lithium, sodium and potassium react vigorously with water, producing an alkaline metal hydroxide solution
It also produces hydrogen gas which is why it fizzes
Group 1 reactivity
Elements become more reactive as they go down the group
The elements are more reactive as atomic number increases
Periods
the rows of the periodic table, the properties of the elements change as you go along
Groups
The columns of the periodic table
The properties of the elements change as you go down the groups
Elements in the same group have similar chemical properties because they have the same number of electrons on their outer shell
Group 0
noble gases eg. neon, helium, argon
They are all inert and have a full outer shell
Properties of chlorine
Green, gas at room temperature
Properties of Bromine
Red brown, liquid at room temperature
Properties of Iodine
Dark grey, solid at room temperature
Properties of Group 7 elements
They gradually change as you go down the group
atomic number increases
Have a darker colour
Higher boiling point
The higher up the more reactive as the positive cycles has a stronger pull
Hydrogen chloride gas dissociates in water
Hydrogen can combine with halogens to form hydrogen halides
When hydrogen chloride is placed in water the molecules split into H+ and Cl- ions
Displacement reactions
Redox reactions where the more reactive element “pushes out” the less reactive element from the compound
Components of the atmosphere
78% nitrogen
21% oxygen
nearly 1% argon
0.04% C02 and water vapour
Copper reaction to find the volume of oxygen in the air
When reacted with the air copper makes copper oxide and uses up oxygen
Using two syringes the markers determine how oxygen has been used up
2Cu + O2 -> 2CuO
Iron or Phosphorus to remove oxygen from the air
Use iron wool and acetic acid, place upside down in a beaker of water
Over time the level of water in the test tube will rise because the iron reacts with the oxygen in the air to make iron oxide, the water then rises to fill the space the oxygen took up
White Phosphorous can be used as it smoulders in the air to produce phosphorous oxide
Making Oxygen from hydrogen peroxide
The hydrogen peroxide with decompose into water and oxygen
The oxygen is then collected over water using an upside down measuring cylinder delivery tube to collect the bubbles of gas
Or using a gas syringe
Burning Magnesium to react with oxygen in the air
Magnesium burns with a bright white flame and forms magnesium oxide which is alkaline
Burning Carbon to react with oxygen in the air
It will only burn if heated very strongly
It has an orangey/yellow flame and produces carbon dioxide which is acidic
Burning Sulfur to react with oxygen in the air
It burns with a pale blue flame and produces sulfur dioxide which is acidic
Producing Carbon dioxide from Calcium carbonate
Marble chips and dilute hydrochloric acid is reacted to form calcium chloride, water and CO2
Collect using downward delivery or a gas syringe
Thermal decomposition of metal carbonates
This forms carbon dioxide
Heat metal carbonates, an example of thermal decomposition:
CuCO -> CuO + CO2
then collect using downward delivery
Properties of carbon dioxide
Slightly soluble
More dense than air
Uses of Carbon dioxide
It is used in carbonated drinks to make them fizz and it dissolves into the drink under pressure and thus produces a slightly acidic solution due to the formation of carbonic acid
It is used in fire extinguishers as it is more dense than air so sinks onto the flames and stops the fire from getting oxygen
Production of Acid rain
All rain is slightly acidic because of the solution made when carbon dioxide reacts with water
When sulfur dioxide mixes with clouds it forms sulphuric acid
Nitrogen oxide also forms nitric acid this way
Problems caused by acid rain
Kills trees, damages limestone buildings and stone statues
Causes lakes to become acidic thus killing animals
Dilute hydrochloric and sulphuric acid with magnesium/ aluminium/zinc/iron
acid + metal > salt + hydrogen
eg. magnesium + hydrochloric acid > magnesium chloride + Hydrogen
Mg + 2HCl > MgCl2 + H2
Describe the combustion of hydrogen
Hydrocarbon fuels contain carbon and hydrogen. During combustion, hydrogen is oxidised to water.
In general: hydrocarbon + oxygen → carbon dioxide + water
Describe the combustion of anhydrous copper sulfate in the chemical test for water
When it is bound to water it forms blue crystals, heating it will drive the water off
If you want to test for water, add anhydrous copper sulcate and see if the white powder turns blue
