2(a, b, c) Flashcards
What are the elements in group 1 of the periodic table called and what are their properties?(3)
Group 1 are the alkali metals.
They have low melting and boiling points for metals and their densities increase down the group.
These metals are also very soft and easily cut with a knife becoming softer as you go down the group.
What are the reactions with water of elements in group 1 and what is the observed trend?(2)
As you go down the group, the metals are more reactive. They all react quickly with oxygen in air to form oxides and all react rapidly with water to form strongly alkaline solutions.
This is why they are called alkali metals. They increase in reactivity as you go down the group because the further down the group the greater shielding effect of the electrons meaning that outer electrons require less energy to be lost.
What are the elements in group 7 of the periodic table called and what are their properties?(3)
Group 7 are the halogens.
The name ‘halogen’ means ‘salt-producing’. When they react with metals, they produce a wide range of salts.
The melting and boiling points increase down the group, and all halogens are covalent molecular substances.
What are the colours and physical states of each halogen at room temp?(4)
Fluorine is a gas at room temp and is yellow.
Chlorine is also a gas at room temp and is green.
Bromine is a liquid at room temp and is red-brown as a liquid but orange/brown as vapour.
Iodine is a solid at room temp and is grey as a solid but purple as vapour.
What is the trend of displacement reactions involving the group 7 elements and why?(2)
As you go down the group of Halogens, reactivity falls.
This is because the force to bring the 8th electron in the outer shell decreases as the mass increases because the shielding effect increases.
What are the percentages of the four most abundant gases in the air?(3)
Nitrogen - 78.1%. Oxygen - 21.0%
Argon - 0.9%. Carbon Dioxide - 0.04%
How can you prove through using Copper to show that the air is roughly 21% oxygen?(5)
Set up two syringes, one pushed all the way in and the other moved out to 100 cm3. These are connected with a silica tube packed with copper filings.
Heat the silica tube and push in the tube that is 100cm3 let out. This will cause air to pass over the copper and push out the plunger on the other side.
Continue pushing either tube in to push the other one out until all of the pink-brown copper turns black forming copper(II) oxide.
Finally, after there is no more change in volume, stop pushing the plungers and measure the final volume of gas in 1 syringe after the apparatus has cooled.
The final volume of air should be roughly 79cm3, because the 21% of Oxygen of the 100cm3 reacted with the copper.
How can you prove through using Phosphorus that the air is roughly 21% oxygen(5)
Place phosphorus on an evaporating basin in a bell jar floating in water on a trough.
The initial level of the water is the same in the bell jar and outside the bell jar in the trough. This is marked with a pen.
The bung is removed, phosphorus is touched with a hot metal wire to ignite it, the bung is replaced.
The phosphorus will burn and the jar becomes filled with white smoke and the level of water rises inside the bell jar.
When the level of water inside the bell jar stops rising, the final level is marked. This bell jar is turned upside down and filled with water to each mark and measured with a large measuring cylinder.
Describe how Magnesium burns in air?(2)
Magnesium burns in oxygen with an extremely bright white flame.
It produces a white powdery ash that is magnesium oxide. This is not very soluble, but tiny amounts dissolve to form an alkaline solution.
Describe how Sulphur burns in air?(2)
Sulphur burns in oxygen with a blue flame. A poisonous and colourless gas, sulphur dioxide is produced.
Sulphur dioxide dissolves in water to form acidic solution of sulphurous acid(different to sulphuric acid).
Describe how hydrogen burns in air?(2)
Hydrogen burns in oxygen with a pale blue flame.
Water is produced.
How does increasing amounts of Carbon Dioxide in the atmosphere lead to climate change?(5)
Carbon dioxide is produced when fossil fuels burn. It is a greenhouse gas.
The greenhouse effect occurs when high-energy UV and visible light from the sun pass through the atmosphere and warm up the surface of the Earth.
The surface of the Earth radiates infrared radiation, which is absorbed by molecules such as CO2 in the atmosphere.
These then give out energy again in all directions, heating the atmosphere.
This overall warms up the atmosphere which could then lead to polar ice caps to melt, rise in sea levels and more extreme weather.
