anyone willing to look at my industrial chem responses? lol (1 Viewer)

[gunat61]

[FONT=&quot]Evaluate how environmental issues are addressed in the Solvay Process (7 marks):[/FONT]
how much would you give this? and how could you improve this? thanks



[FONT=&quot]The Solvay Process involves the addition of brine (sodium chloride) with limestone (calcium carbonate) and can be summarised by the following equation:[/FONT]

[FONT=&quot]NaCl(aq) + CaCO3(aq) [/FONT]à[FONT=&quot] Na2CO3 (aq) + CaCl (aq)[/FONT]​

[FONT=&quot]The disposal of CaCl (aq) is an issue because only some of what is disposed is recycled for use including the de-icing of roads, the use of it as a concrete additive and also as a drying agent. Once CaCl (aq) enters waterways it can result in detrimental effects on freshwater life if the solution is not diluted due to the chloride ions present. The chloride ions increase the salinity of rivers and lakes which negatively impacts on the health of living organisms in such locations.Also, to address excess alkalinity of waters, which affect living organisms, this environmental issue is naturally addressed as hydrogen carbonate ions neutralize it; summarised by the following equation: [/FONT]

[FONT=&quot]OH-[/FONT][FONT=&quot](aq) + HCO3- (aq) <> H20(l) + CO32-[/FONT]​

[/FONT]

[FONT=&quot]Thermal pollution can arise from the Solvay process due to some of the reactions producing large amounts of heat, some of up to 95-100 degrees Celcius. The heated water cannot be released back to where it was taken from as this would lead to excessive thermal pollution. To address this issue, cooling towers and heat exchangers are used to cool the water and then it is discharged. Although the discharged water is still warm, it does not result in reduced levels of dissolved oxygen or damage to organisms present in freshwaters.

[FONT=&quot]The decomposition of limestone is a vital step in the Solvay process which can be summarised by the following equation: [/FONT]

[FONT=&quot]CaCO3(aq) [/FONT]à[FONT=&quot] CaO(aq) + CO2 (g)[/FONT]​

[FONT=&quot]During the decomposition of limestone in a kiln, some uncalcined limestone is produced as the kilns are not 100% effective. However, to address the problem, these can be sold to farmers which use this uncalcined limestone to treat acid soils. In addition, particle emissions from kilns can be controlled by scrubbers and electrostatic precipitation. [/FONT]

[FONT=&quot]In hindsight, this process uses many natural products thus there are no major environmental issues associated with the chemical pollution of the environment, however, good procedures have been developed to address disposal problems. [/FONT]

 

[Amogh]

Make sure your equations are right! It's CaCl2
Talk about ammonia lost to the environment as well (green house gas etc. etc.) and mining CaCO3
Why exactly do you mention the importance of hydrogen carbonate/carbonate as a buffer? You say that CaCl2 increases salinity, and then jump to talk about pH
Use of 'however' as the conjunction in your judgement doesn't make sense. You say something advantageous of the Solvay process and then say, 'however' :S (Generally its a 'bad thing', however dah dah dah 'good thing' or vice versa)
Apart from that, don't think you're lacking much. Make sure you address the specific question rather than regurgitating this response (It applies to Science as well English )
May scrape a 6ish right now, imo.

 

[jamesfirst]

Given that the option questions have no 'limit' to how much you can write, I would first describe the production of each (not all, just the ones that your gonna relate to the effects)



Also, this is another disadvantage:


- Raw material such as CaCO3 must be dug up from the limestone deposit, meaning that the earth will subside into the cavity and natural habitats are destroyed. To address this problem, another source of raw materials must be introduced.... such as reactions of something to produce CaCO3 (dont know what it is haha)


Other than that, it's all good. Remember you have to add a judgment for evaluate verb

 

[gunat61]

thanks guys .. amogh, tbh ... i just wanted an excuse to put in another equation hahaha. cos for a 7 mark question, i dno, i think they'd expect at least 3 equations right? cos i remember in my trials we needed 4 for a 6 mark question :S.. but i guess it depends. what kind of judgement do you give?? that last sentence was meant to be my judgement LOL but yeah, obviously i can't write good judgements

 

[Riproot]

Given that the option questions have no 'limit' to how much you can write, I would first describe the production of each (not all, just the ones that your gonna relate to the effects)

They have writing booklets for the options now that resemble the rest of the test, with the question and then lines underneath it.

 

[jamesfirst]

They have writing booklets for the options now that resemble the rest of the test, with the question and then lines underneath it.

You mean... they are limited ?