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Basic Test 2- chemistry (cover form 5 syllabus)
ANSWERS
1) An experiment excess zinc granules was reacted with hydrochlo...
2
• Therefore rate of reaction increase
• Catalyst
• Presence of catalyst will provide an alternative path to the reaction...
3
• Glacial ethanoic acid in water ionize to form hydrogen ions
• This shows acidic property
6) Draw cross section of late...
4
9)
a) State homologous series for propane ……alkane……….
b) Name for reactions
i) Reaction 2 ………substitution reaction……
ii...
5
Reaction 3 nC3H6  (C3H6)n
Reaction 5 …………… C3H7OH  C3H6 + H2O
Reaction 7 ………………………………………………………
d) What is the function...
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f) State general formula for homologous series of compound W …………………………
g) State:
i) Molecular formula of W ………………………………...
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f) State general formula for homologous series of compound W …………………………
g) State:
i) Molecular formula of W ………………………………...
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Jawapan revision chemistry 2010 test 2222

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Transcript of "Jawapan revision chemistry 2010 test 2222"

  1. 1. 1 Basic Test 2- chemistry (cover form 5 syllabus) ANSWERS 1) An experiment excess zinc granules was reacted with hydrochloric acid 100cm3 of 1.0 moldm-3 at room temperature Diagram below shows graph of volume of gas against time On the graph above, sketch the graph with repeated experiment( all other conditions remain the same) i) Excess zinc powder ii) Temperature of 20 oC iii) Hydrochloric acid 400 cm3 concentration 0.5 moldm-3 2) Explain the effect of these two factors on rate of reaction using collision theory • Temperature • The higher the temperature of the solution, the higher the kinetic energy of particles/ions • More particles will collide//Frequency of collisions between ion/particles increase • Frequency of effective collisions between ion/particles increase Volume of gas Time taken
  2. 2. 2 • Therefore rate of reaction increase • Catalyst • Presence of catalyst will provide an alternative path to the reaction • This path has a lower activation energy than the original path without the catalyst • More particles will overcome the activation energy for the reaction to occur • Frequency of effective collisions between ion/particles increase • Therefore rate of reaction increase 3) Draw i) Soap particle ii) Detergent particle 4) Explain why detergent is more effective than soap in hard water? • Hard water contain magnesium ion and calcium ions • Detergents do not react with hard water to form scum • Therefore detergent is not wasted • Soap react with hard water to form scum, thus cause waste of soap 5) Explain why no bubbles of gas when magnesium ribbon is added to Glacial ethanoic acid but there is bubbles of gas when magnesium ribbon is added to glacial ethanoic with water • Glacial ethanoic acid does not contain water • Therefore no hydrogen ion to show acidic property
  3. 3. 3 • Glacial ethanoic acid in water ionize to form hydrogen ions • This shows acidic property 6) Draw cross section of latex particle 7) Explain why latex coagulate when acid is added to it. • Acid contain hydrogen ion which is positively charge • This will neutralize the negatively charged membrane of the rubber particle • So, the rubber particles no longer repel each other • The particles collide • Break the protein membrane • Some polymers are released and • Combined with each other • To form coagulation 8) When ammonia is added to latex, it does not coagulate. Why? • Ammonia contain hydroxide ions which are negatively charge. • This will neutralize the hydrogen ions that is produced • From bacteria in the air • Therefore the membranes remain negatively charged and • Latex particles repel each other • Membranes do not break// polymers are not released Carbon dioxide and oxygen Acidified K2Cr2O7 Rex I
  4. 4. 4 9) a) State homologous series for propane ……alkane………. b) Name for reactions i) Reaction 2 ………substitution reaction…… ii) Reaction 3 ………… polymerisation reaction ……. iii) Reaction 5 …………… dehydration reaction ……… iv) Reaction 7 …………… oxidation reaction …… v) Reaction 8 …………… esterification reaction ……. c) Write equation for reaction 1 …………… C3H8 + 5O2  3CO2 + 4H2O Propane Propene W Propyl ethanoat Bromine in UV light X polypropene Q Rex 4 Rex 5 Rex 6 Rex 7 Rex 8 Rex 2 Rex 3
  5. 5. 5 Reaction 3 nC3H6  (C3H6)n Reaction 5 …………… C3H7OH  C3H6 + H2O Reaction 7 ……………………………………………………… d) What is the functional group of propene? ……………………………………. e) Draw diagrams for experiment in i) Reaction 5 ii) Reaction 8
  6. 6. 6 f) State general formula for homologous series of compound W ………………………… g) State: i) Molecular formula of W ………………………………………. ii) Structural formula of W ………………………………………… h) State observations for reactions i)reaction 7 …………………………………………………. ii) reaction 8 ………………………………………………………………. i) State conditions for reactions i) Reaction 4 ………………………………………………………………….. ii) Reaction 6 ………………………………………………………… iii) Reaction 8 ……………………………………………………… END..work hard, time is running short……………
  7. 7. 6 f) State general formula for homologous series of compound W ………………………… g) State: i) Molecular formula of W ………………………………………. ii) Structural formula of W ………………………………………… h) State observations for reactions i)reaction 7 …………………………………………………. ii) reaction 8 ………………………………………………………………. i) State conditions for reactions i) Reaction 4 ………………………………………………………………….. ii) Reaction 6 ………………………………………………………… iii) Reaction 8 ……………………………………………………… END..work hard, time is running short……………

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