I have one now but it took me long to get it so please rep
Sorry but I don't have all the answers. Hope I helped anyway.
This is c2 aqa gcse june 2013
1ai) As the number of spatula measure of sodium hydroncarbonate increases, so too does the change in temperature, this reaches its optimum change, 10 degrees, at 8 spatula measures. However, the Final temperature decreases as the number of spatula measures increase, this levels off at 6 spatula measures, at around 10 degrees. The start temperature however remains around 20 degrees for the entirety of the spatula measure increases.
1aii) Exothermic
1bi) The release of CO2 causes cake batter and bread dough to rise.
1bii) It would need to be heated to overcome the activation energy.
1ci) 23+1+12+ (16*3) = 84
1cii) 84/100*12 = 14.29%
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2a) 1 – The loss in mass in grams – hydrogen gas is given off (Hence)
2 – The time it takes for the loss of mass – hence time in seconds being a factor.
2b)
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3ai) moles* atomic mass, 5.6 tons
3aii) 61.76 – actual*100 / predicted
3aiii)
3b) Take readings of mass at regular time intervals
Put the results in a table and work out the los sin mass for each reading. Plot a graph.
Repeat with more concentrated acid solutions, but always with the same amount of magnesium.
The volume of avid must always be kept the same too - only the concentration is increased.
The three graphs show the same old pattern - a higher concentration giving a steeper graph, wit hthe higher reaction finishing much quicker.
3ci) Hydroxide ions
3cii) Precipitation reaction
3ciii) nitric acid
3civ) (NH4)2SO4
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4aii) he was a professor of chemistry so his opinion was well respected
4b) both potassium and hydrogen are attracted towards the negative electrode
- as hydrogen is the least reactive metal it forms at the electrode
- these hydrogen ions from water become hydrogen atoms and bond to each other, forming hydrogen gas molecules
4ci) Potassium ions are formed when the atom loses a single electron due to a bond with another atom(s).
4cii) 2Cl- ---> Cl2 + 2e-
4ciii) 2, 8, 8
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5a) an alloy is stronger than pure metal because in a pure metal all the atoms are the same size and ordered. Alloys have a mixture.
5b) Diamond has a giant molecular structure. Each carbon atom is covalently bonded to four other carbon atoms. A lot of energy is needed to separate the atoms in diamond. This is because covalent bonds are strong, and diamond contains very many covalent bonds. This makes diamond's melting point and boiling point very high.
There are no free electrons or ions in diamond, so it does not conduct electricity.
5c) Thermosoftening polymers soften when heated and can be shaped when hot. The shape will harden when it is cooled, but can be reshaped when heated up again. Poly(ethene) is a thermosoftening polymer. Its tangled polymer chains can uncoil and slide past each other, making it a flexible material. thermoSOFTENING plastics are flexible and MELT when heated.
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6a) Carbon is a non-metal with a fairly small atomic radius close to that of oxygen. Carbon dioxide consists of molecules in which a single carbon atom is double-bonded to two oxygen atoms. As CO2 is a relatively small, nonpolar molecule it is a gas. Because the room temperature is way above its boiling point -57 °C
6bi) The purpose of the gas chromatograph is to separate mixtures into individual components that can be detected and measured one at a time.
6bii) The recorder draws a gas chromoatograph. The number of peaks shows the number of different compounds in the sample
position of the peaks show teh retention time of each substance.
6ci) Ph 2
6cii)
6d)