Chemistry-unit12k15 Flashcards
What is the mass number
Number of protons plus neutrons
What doesn’t an atom have any charge
This is because they have the same number of positively charged protons in the nucleus, as the number of negatively charged electrons in their shells
The periodic tables groups?
This is because they have the same number of electrons in their outer shell (7 electrons) and therefore have similar chemical properties
Tick the correct box
Sulphur
Particles that include non metal and metals
Ions
Particles that include two non metals
Molecules
Limestone is calcium ___________. Calcium oxide is produced through ______________ _______________. Calcium hydroxide is created by adding __________
Carbonate
Decomposition
Water
How can limestone be used to neutralise acids?
It’s an alkali
Line of best fit
Line of best fit
How could the accuracy be improved?
By repeating the step shown in figure 2 and calculating an average
Estimate the force needed for 0g from the graph?
45N
Why isn’t the prediction about the trend correct
Because after 400g , the force needed begins to decrease as for 700g, the force needed is 100N
Why are there so many theories?
There is a lack of reliable evidence from the time. Also some evidence conflicts causing many theories
Change in the earths surface area and atmosphere
In the early atmosphere, billions of years ago, it is thought that due to intense volcanic activity, in the earths atmosphere, there was a lot of carbon dioxide, water vapour and small proportions of methane and ammonia. However, this changed as the earths atmosphere began to cool down, the water vapour condensed to form oceans. This caused a lot of the carbon dioxide within the air to dissolve into the water and removing lots of it from the atmosphere
Why was stage 2 necessary
So that the ore is concentrated meaning that the metal produced will be purified, ridding of any impurities found within the ore. This is why there is a separation so that when the metal is extracted, no impurities will be within
Why isn’t cast iron suitable for pylons
It’s too brittle
Describe the process shown in the diagram
Cast iron + oxygen –> waste gases + steel
Cast iron is heated in a furnace in the presence of oxygen, so that it can form an alloy with carbon to produce steel
Why is aluminium more suitable for pylons than copper
It’s less dense therefore lighter
From the periodic table, how can we tell that copper is a transition metal
It is found in group 3 meaning it has only 3 electrons in its outer shell. Moreover, as it is in this certain group, it’s charges of ions can have only one set charge
How is copper extracted from copper salts using irons
As iron is more reactive than copper, the scrap iron can displace the copper within the copper ions so that the copper produced will be pure
How are fractions of oils separated?
- crude oil enters at the bottom of the fractionating column
- heated at around 350 degrees
- top is cooler, bottom is hotter
- hydrocarbons have different boiling points
- they separate at different boiling points
- they evaporate into a gas and rise till they condense into liquid forms
- they are separated into fractions
- exit out of the tube
Suspension of limestone
Sulphur dioxide and nitrogen are slightly acidic and react with calcium carbonate to produce a salt
C2H4
C2H4
What is the atomic number
Number of protons
