How's this?
Code:
1. A
2. D
3. B
4. C
5. D
6. C
7. D
8. C
9. A
10.C
11.B
12.A
13.A
14.D
15.B
1. Ethanol is renewable.
2. Glucose undergoes condensation polymerisation to form cellulose whilst producing a small by-product often water.
3. Electrons travel through the external wire from the anode to the cathode. Salt bridge is for migration of positive ions.
4. A saturated 7-carbon chain (heptan-). Since the OH is closest to the right, counting from the right, we get 3.
5. From the standard electrode potentials table, Mg and Pb gives the highest difference in voltage.
6. Phenolphthalein turns pink in basic solutions. Only NaOH is basic from the given list.
7. Neutralisation is exothermic, thus ΔH must be negative. D is the only graph where ΔH is negative.
8. Since they are both weak, neither has completely ionised. X is stronger than Y, making X more ionised than Y, thus X has the lower pH.
9. Sodium citrate is the salt from a strong base and weak acid, thus making it slightly basic (i.e. pH > 7). Besides, sodium chloride is neutral and ammonium salts are slightly acidic, ruling the other 3 out.
10. I won't go through the calculations here, but if you add 810 mL and since the initial volume was 90 mL, the total volume would be 900 mL, thus making the final solution more dilute by a factor of 10 (and since pH = -log
10[H
+]...)
11. Mg and Ca ions contribute to water hardness.
12. Water is always produced in the combustion of fossil fuels. Soot is only produced in incomplete combustion. When burning pure hydrocarbons, sulfur dioxide won't be produced. In extreme cases of incomplete combustion, carbon dioxide won't be produced at all.
13. Since ΔH is negative, heat is released when the reaction proceeds to the right, and vice versa (i.e. heat is absorbed when the reaction proceeds to the left). A decrease in pressure will cause the reaction to proceed to the left since there are 4 moles of gases on the left whilst only 2 moles on the right, thus resulting in the absorption of heat.
14. AAS is highly accurate, so it
is used for quantitative analysis. Electrons falling to their ground state
emit a photon (i.e. light). This is Atomic
Absorption Spectroscopy (not
Emission). A lamp emitting only the wavelengths of light absorbed by a particular element is used, not 'continuous' white light. To detect a metal ion, say, mercury, a mercury lamp is used, which basically excites (by heating) the electrons in mercury atoms, causing them to enter a higher energy state. When they fall back to their ground state, they
emit a photon. This is the same principle as that in a
flame test.
15. From the two equations given, •Cl is present at the start and •Cl is present at the end - in the same state/condition. Thus, it would be best classified as a catalyst.
Hope that helps. Multiple choice was easy. The other parts were... ok. For anybody that's interested, I made up my scientist.
Where are all the people that did Shipwrecks?
