ANSWER PAPER 1

ANSWER FOR PAPER 1 SPM 2013

1	D	26	C
2	A	27	D
3	D	28	D
4	C	29	C
5	B	30	B
6	C	31	A
7	B	32	B
8	C	33	A
9	A	34	D
10	** B/C	35	D
11	D	36	A
12	B	37	A
13	C	38	D
14	C	39	B
15	D	40	A
16	D	41	D
17	C	42	C
18	B	43	A
19	A	44	B
20	B	45	C
21	D	46	D
22	A	47	A
23	B	48	B
24	C	49	A
25	C	50	C

question 10

B  fats found in animal but oil found in vegetables and fishes ( animal right?）

C  Fats are mixtures of organic acid( fatty acid/ carboxylic acid is organic acid)  and glycerol.

so hopefully this question is a bonus for students.

Electrolysis Of Molten Compounds

Electrolysis Of Molten Compounds

Process of breaking down compounds in molten or aqueous state into their constituent elements by passing electricity through them.

v  Anode (Positive electrode)

─       Negative ions or anions are attracted to anode.

─       Anion undergo discharge by releasing electrons to form neutral atoms.

v  Cathode (Negative electrode)

─       Positive ions or cations are attracted to cathode.

─       Cation  undergo discharge to form atoms.

Electrolysis Of Molten Lead (II) Bromide

v  Anode (Positive electrode)

─       Anions, Br ^- are attracted to the anode.

─       Bromide ions, Br^- discharge by releasing electron to form bromine gas, Br₂

Half equation :

2Br^-(l)      →       Br₂(g) + 2e^-

v  Cathode (negative electrodes)

─       Lead(II) ions, Pb²⁺ are attracted to the cathode.

─       Lead (II) ions, Pb²⁺ undergo discharge by accepting two electrons to form a lead atom/lead metal.

Half equation :

Pb²⁺ (I) + 2e^-       →         Pb (s)

Overall equation:

Pb²⁺ (I) + 2Br ^-  → Pb(s) + Br₂(g)

Electrolytes & Non-Electrolytes

Electrolytes

v  Substance that can conduct electricity in molten state or aqueous solution.

v  Contains free moving ion that carry electrical charges.

v  Ionic compounds such as molten lead (II) chloride, PbCI₂.

v  Acid solutions such as nitric acid, HNO₃.

Non-Electrolytes

v  Substance which cannot conduct electricity in all states.

v  Made from molecules only-no ions that can carry electrical charges and conduct electricity.

v  Covalent compounds such as alcohol, sugar and naphthalene.

Elements In A Period

Elements In A Period

v  The Change In The Physical Properties of Elements Across Period 3

1)      Proton number increases by one from one element to another element.

2)      Number of valence electron increases by 1.

3)      Physical state change from solid to gas.

4)      Atomic radius (atomic size) of elements decreases because:

Ø  Force of attraction between nucleus and valence electron increases.

Ø  The stronger the force of attraction, the smaller the atomic size.

5)      Electronegativity of element increases because:

Ø  As the size of atom decreases, force of attraction between nucleus and valence electron increases.

Ø  Thus, the strength of the atom to attract electrons to the nucleus increases.

Ø  Metallic properties decrease across the period.

v  The Changes In Oxide Properties of Elements Across Period 3

The properties of the oxide of elements in Period 3 change from basic to acidic

Na2O MgO	Basic oxides	§  Metal oxides are basic. §  Metal oxides dissolve in water to form alkaline solution. v  Example: Na2O (s)  +  H2O (l) →  2NaOH (aq)
Al2O3	Amphoteric	§  Amphoteric means oxide that shows both properties of acid and base. v  Examples: Al2O3 (s)  +  6 HCl (aq) →  2AlCl3 (aq)      +      3H2O (l) Al2O3 (s)   +   2 NaoH (aq)  →  2NaAlO2 (aq)  +  H2O (l)
SiO2 P4O10 SO2 Cl2O7	Acidic	§  Non-metal oxides are acidic. §  Non-metal oxides dissolve in water to form acidic solutions. v  Example: SO2 (s)   +   H2O (l) → H2SO3 (aq)

Transition Elements

Transition Elements

Ø  Elements that is located in Group 3 to Group 12 in the Periodic Table.

Ø  Examples: scandium, iron, nickel, tungsten and copper

Physical  Properties:

§  Solid

§  Shiny surface

§  Ductile and malleable

§  Good conductor of heat and electricity.

§  High density.

§  High melting point and boiling point.

Special characteristics

v  Show different oxidation numbers in their compounds.

v  Form coloured ions or compounds.

v  Act as catalyst.

v  Form complex ions.

•          These characteristics are not possessed by other metals.

Ions	Colour of aqueous solution
Fe2+	Green
Fe3+	Yellow/ brownish yellow/ brown
Mn2+	Pink
MnO4-	Purple
Cr2O72-	Orange
CrO42-	Yellow

The Uses Of Transition Metals In Industries

Process	Manufacture	Catalyst
Contact Process	Sulphuric acid, H2SO4	Vanadium oxide, V2O5
Ostwald process	Nitric acid, HNO3	Platinum
Haber process	Ammonia, NH3	Iron
	Margarine	Nickel