Comments:
Shin Yong: Her answers are very clear and understandable. She makes the effort to change the font sizes and everything, which can be very tedious.
Jiale: He organised his answers very well which makes it very easy to read. Very nice blog, nice background and layout.
Chun boon: He puts in effort in his work and his answers and my answers are very similar and i can hardly find any mistakes in his blog. But his blog is abit plain.

Q1 Zinc nitrate reacts with aqueous ammonia (NH4OH) to form a salt and a base.  
(i) Name the salt and the base.
The salt is Zinc hydroxide.The base is Ammonium nitrate.
(ii) Describe the observations for the reaction. 
A white precipitate is formed when the two aqueous solutions(Zinc nitrate and aqueous ammonia)are introduced to each other.
(iii) Write a chemical equation for the reaction (include state symbols). 
ZnNO3(aq)+NH4OH(aq)-->ZnOH(s)+NH4NO3(aq)
(iv) Write an ionic equation for the reaction. 
 Zn(+)(aq)+OH(-)(aq)-->ZnOH(s)

Q2 Ammonium sulfate is heated with sodium hydroxide. 
(i) Write a chemical equation (include state symbols) for the reaction. 
 (NH4)2SO4(aq)+2NaOH(aq)-->Na2SO4(aq)+2H2O(l)+2NH3(g)
(ii)  Describe a test for the gas. 
Hold a piece of damp red litmus paper above the solutions reacting.

Q3. An unknown green solution is heated with a piece of aluminium foil and sodium hydroxide solution.

(i) The gas produced turns damp red litmus paper blue.  Name the gas evolved.

The gas evolved is Ammonia gas.

(ii) This is a confirmatory test for an anion.  Name this anion.

It is Nitrate.

(iii) Give a possible cation which gives the green solution.

Iron (III) ion. 

Q4.  Sulfuric acid is titrated with potassium hydroxide in the preparation of potassium sulfate salt. 

(i) Explain why this method is recommended for the preparation for this salt.

This is because Potassium Sulfate is a colourless soluble salt and there is no suitable metal, metal oxide, metal hydroxide or metal carbonate that is insoluble in water to react with it. Therefore, titration is the only way to prepare it.

(ii) Write an ionic equation for the reaction.

H(+)(aq)+OH(-)(aq)-->H2O(l)Q5 Excess zinc carbonate is added to hydrochloric acid in the preparation of zinc chloride salt. 
(i) Write an ionic equation for the reaction. 
ZnCO3(s)+H(+)(aq)-->Zn(+)(aq)+H2O(l)+CO2(g)
(ii)  Why excess zinc carbonate is used? 
To ensure the complete reaction of the hydrochloric acid with the zinc carbonate.
(iii) Briefly explain how the zinc chloride crystals can be obtained.
After the reaction of the zinc carbonate with the hydrochloric acid,filter and heat the filtrate until there is a small amount of water for crystalization.

Here the pictures you asked for, Mr Tan(: I done my chem assignment too.

Sodium (2.8.1) has a valency of 1, thus it will lose 1 electron during chemical process, and it will become a positively charged ion. Sulfur (2.8.6) has a valency of 6, thus it will gain 2 electrons during chemical process, and it will become a negatively charge ion. Sodium is found in group I in the periodic table and Sulfur is found in group VI in the periodic table. Therefore sodium is metal and sulfur is non-metal. The physical properties of metal is that it conduct electricity well and non-metal is a poor conductor of electricity.

Image from: http://www.simplechemconcepts.com/o-level-chemistry-periodic-table-mini-series-part-iii//

Ans 4) Chlorine-35 atom and Chlorine-37 atom are called isotopes... Use these two examples to explain what is 'isotopes'.

Defination of iostopes, different atoms of the same element which have the same number of protons but different number of electrons.

Chlorine-35 have a proton and neutron no. of 35.
Chlorine-37 have a proton and neutron no. of 37.
Both have the same number of 17 protons.
Chlorine-35 has 18 neutrons (35-17=18)
Chlorine-37 has 20 neutrons (37-17=20)

Therefore, Chlorine-35 and Chlorine-37 are isotopes.

{/Chemistry Ans 3) --

( 10:19 PM )

Ans 3) Draw the atomic structure of a sulfur atom and a sulfide ion... Explain why you draw it in this way. Sulfur has a valency of 6. Sulfur needs to accept two electrons to achieve a full shell (2.8.8). When sulfur gains two electrons, sulfide ion is formed.

QUESTIONS

1. What does an atom looks like?  
What are the sub-atomic particles inside it.....(talk about electrons, neutrons, protons, electron shells, nucleus....)

This is an example of an Atom. 

Atom; It is the basic unit of matter that consists of a dense, central nucleus surrounded by a cloud of negatively charged electrons.
Subatomic particles; The smaller particles composing nucleons and atom

An atom consists of protons, electrons and neutrons. These particles are smaller than the atom, thus they are called subatomic particles.

Electron; It carries a negative electric charge and it is a subatomic particle It does not have any components or substructure. . It has a mass of 1/183. The smallest part of an atom and it is found in the atom's shell
Protons; The number of protons in the nucleus of an atom is called the proton number or an atomic number. relative charge of the proton is +1 and relative mass is 1
Neutron ; The are large and heavy like protons, however it does have no electrical charge. It has the exact same mass as the proton.


2.Draw the atomic structure of a sodium atom and a sodium ion....
explain why you draw it this way.

The sodium atom is drawn this way as its electronic configuration is (2.8.1) It only has one electron on its last shell. 

The sodium ion lost its last shell consisting of 1 election causing its electronic configuration to be only (2.8), making it stable