National Chemistry

2009 Credit HINTS

Credit 2009   First thoughts
  Hints
 
  SQA Answers

1. get rid of wrong answers - eg pH indicator tests for what ?
(a) What type of compound is maltose ?
(b) 'Fe' test
Unlikely that same answer will be corect for both questions.

2. (a) Find flame test in data book.
(b) Write out electronic arrangement of argon 2,8,8
Write out electronic arrangement of all of the ions (two) in each box.
eg B is 2 and 2,8 (from 2,1 and 2,6)
Takes time but just work through patiently.

3.(a) Network boiling point - high or low? High
When does covalent conduct?
(b) What bonding in calcium fluoride? Does it contain a metal ? yes

4. (a) Reacts with acid. remember the three substances that you used on acids.
Get rid of salts.
(b) Page 5 of data book. You will have to attempt each pair.
eg A and B will form aluminium chloride and sodium bromide. Takes time but just work through patiently.
 (c) Write the charge on the ions above each name.
eg for A it is 2+ and -1;
Any pair of charges that appear twice will obviously be a wrong answers
Takes time but just work through patiently.

5. Write in the molecular formula if you can. At least write in the number of carbon atoms using page 6 2, 5, 6, 5, 5, 3
(a) A definition you should know. Same molecular formula .....................
(b) page 6 of data book. Write the figures into the box.
(c) Need a pair - you have two cyclos, two enes and two anes.
What does an addition treaction need?

6.(a) Must make a hydrogen ion.
(b) What gas do fuesl burn in? Must be a reactant.
(c) Involves iron. Corrosion is oxidiation.

7. ppppprotons
Mark in each box if it refers to protons, neutrons or electrons

8. Fraction six is collected last and is deliberately darker.
Ask yourself if each statement is true or false.
Remember - smallest, lowest, lightest all go together.

part 2

9. (a) protons = atomic number; neutrons need to be calculated.
(b) Definition you should know. Look at the three atoms.
(c) Must be one of the three atoms.
Most will be closest to the average

10. (a) Power supply produces electricity. part (b) tells you the bonding present.
(b) Write out both the ions first. Al3+ and O2-
(c) Since they do something must allow it to happen - ionic compounds!

11, (a) What do each of the observations tell you has been formed ? H2O and CO2
(b) Unlikely to be same results.
What would be formed when hydrogen burns ?

12. (a) What types of bonding are there ? metallic, covalent and ionic.
(b) Draw out the outer electron arrangement for P first of all. 2,8,5

13. (a) Acid reaction?
(b)(i) Something must be lost if mass drops.What does a carbonate make
(ii) Label each axes and make up scale to use up at least half the graph paper.
(c) read up from 3 minutes - make a mark on the graph.

14. (a) (i) Should know two process, named after people, for nitrogen chemistry.
(ii) Platinium catalyst - alphabet clue should answer part (i).
needs heat but you do not have to keep heating??
(b) First off; mass of 1 mole.

15. (a) Circle the boxes which state a reaction has occurred- should give most reactive.
(b) gas from H2O?
(c) Must be extremes. Difficult to name things in the middle

16.(a) starch and water reacting.
(b) Do working beneath. Do hydrogens first since they only appear in one chemical on each side.
  C6H12O6 ----> C2H5OH (6 hydrogens) + CO2
  C2H5OH

(c) Alcohol goes from 8% to 40%.
(d) mass - so calculate mass of 1 mole.
How much nitrogen is in this amount?

17. (a) Involves electrons - use page 7. OIL RIG
(b) Which electrode are electrons made at?
(c) Test for iodine. (Usually you use iodine to test for What ?)
(d) Copy from page 7

18. (a) Look at structure - break into parts which are the same.
Repeating unit and monomers have two main carbons in backbone.
(b) page 6 helps identify the number of carbons. look for the pattern to get the number of hydrogens.
(c) Look at the elements present - what gases are possible.

19. (a) Look at the pattern. Do not get to big.
(b) Definition you should know.
(c) Copy out equation and underline the chemical you are told about and the chemical you are asked about.
  C9H20  + 14O2 -----> 9CO2 + 10 H2O
  1 mole -----> 10 mole
(d) look at the ethane structure and identify (highlight, write over etc) where the 2 carbon and six hydogens came from.
Or try to see where the 2CO2 molecules were formed from and score these atoms out on the treactants.

Do same for question.

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