HSC_Chem_Past_Paper_Sol

1600 right 1367math mathx 0676 gmath question

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Unformatted text preview: ight ) \times \left ( 12.01 \times 2 + 1.008 \times 6 + 16.00 \right )}{1367}</math> <math>x = 0.676 g</math> Question 18: Key Points: Biopol. Impacts on ''Environment'' because: *100% Biodegradable *Renewable Resource Impacts on ''Society'' because: *Biocompatable - Used in stuches and other things that are artificially put inside the human body. As it is biocompatable the body will not reject it. Question 19: Cell X (a) Cannot be recycled or recharged therefore contributes to landfill. :"Candidates are reminded that their answer should identify a specific impact rather than offer a general statement, such as the chemicals harm the environment."<sup>1</sup> (b) :"Better responses included balanced half equations or an overall equation and included identification of the anode, cathode and electrolyte."<sup>1</sup> Cell Y (a) (b) Question 20: Glucose is fermented to produce a mixture containing ethanol. Fermentation, <!-- REACTION _____________________________________________________________________________________________________ HSC CHEMISTRY PAST PAPER SOLUTIONS – ANDREW HARVEY 9 2000 HSC –––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– , is preformed in the presence of a catalyst yeast, warm temperatures (approx 35ºC) and in the presence of CO<sub>2 (g)</sub>. Over several days a mixture with ethanol in it forms. This mixture is fractionally distilled to extract the ethanol (as ethanol has a low boiling point). This gets pure ethanol which is used to produced ethyl butanoate in a process of esterfication. In esterfication, ethanol, concentrated sulfuric acid (used as a dehydrating agent) and butanoic acid is added to a flask which is heated. This mixture reacts forming ethyl butanoate. Refluxing is used in this process to prevent these volatile substances evaporating. (this solution needs another equation and 2 diagrams for a chance of full marks) For 6-7/7 marks: *Provides characteristics and features of the chemistry of fermentation and esterification<sup>1</sup> *Includes two correct balanced chemical equations<sup>1</sup> *Describes procedures in each of three steps including at least one diagram<sup>1</sup> Question 21: (in chronologial order) *Lavoiser hypotheised that all acids contain oxygen. *Davy showed all acids contain hydrogen, rather than oxygen as Lavoiser hypotheised. *Arrehenius showed that acids ionise in water producing H<sup>+</sup> ions as the only charged ions and bases ionise in water producing OH<sup>-</sup> ions as the only charged ions. *Bronsted-Lowry therory says that acids are proton donors and bases are proton acceptors. Question 22: (a) 400 300 volume gas (m...
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This document was uploaded on 09/19/2013.

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