Group 6 (Lim Zheng Xiang 22 Benedict Chin 6 Soo Jian Xian 30 Javier Toh 14)

2P07

Observation

	Sodium Hydroxide + ammonium chloride	Carbon hydroxide + ammonium nitrate
Colour of gas	Colourless	Colourless
Odour of gas	Pungent	Pungent
Effect of gas on damp red litmus paper	Turns blue	Turns blue
Effect of gas on damp blue litmus paper	Remains blue	Remains blue
Name of gas formed	Ammonia gas	Ammonia gas

1. What can you conclude about the reaction between an alkali and an ammonium salt?

Alkali reacts with ammonium salt to produce: Salt +water + ammonia

2. Write the general equation for the reaction:

Alkali + Ammonium salt à Salt + water + ammonia gas

3. Why is it necessary to warm the mixture when we need to test for ammonia gas?

The reaction requires heat energy to break down the bonds in the compound formed before ammonia gas is released.

4. From the effect of gas in damp litmus paper, what can you conclude about the nature of ammonia gas?

It is alkaline

5. When pieces of dry litmus paper are placed above a bottle of aqueous ammonia, there is no visible observation. However, then the experiment is repeated using damp red litmus paper, the damp litmus paper turned blue. What can you conclude from the above observations?

The litmus paper can only show its alkaline properties when it is placed in water. The alkaline properties cannot be observed when it is dry.

6. Substance X is a white solid and is soluble in water. Describe a chemical test to confirm X is an ammonium salt.

1. Dissolve substance X in the water till it is completely dissolved. 2. Heat the solution. 3. Place damp litmus papers (blue and red) over the heated solution. 4. If X is an ammonium salt, the damp read litmus paper will turn blue while the blue litmus paper would remain blue. This is caused by ammonia gas, which is only released when ammonium salt solution is heated.

We are not quite sure for the answer for question 7

Exercise

1 (a) sodium hydroxide +ammonium chloride ->sodium chloride + water + ammonia gas

(b) NaOH(aq) + NH₄Cl à NaCl +H₂O(l) + NH₃(g)

2 (a) sodium hydroxide + ammonium sulfate -> sodium sulfate + water + ammonium

(b) 2NaOH(l) + (NH₄)₂SO₄(aq) -> Na₂SO₄ (aq) + 2H₂O + 2NH₃ (l)

3 (a) sodium hydroxide + ammonium nitrate -> sodium nitrate + water + ammonia gas

(b) NaOH(s) + NH₄NO₃ -> NaNO₃(s) + H₂O (l) + NH₃

4 (a) calcium hydroxide + ammonium chloride -> Calcium chloride + water + ammonia gas

(b) Ca(OH)₂(aq) +2NH₄Cl(s) -> CaCl₂(aq) + 2H₂O (l) + 2NH₃(g)

5 (a) calcium hydroxide + ammonium sulfate -> calcium sulfate + water + ammonia gas

(b) Ca(OH)₂(aq) + (NH₄)₂SO₄(aq) -> CaSO₄ + 2H₂O (l) + 2NH₃(g)

6 (a) calcium hydroxide + ammonium nitrate -> Calcium nitrate + water + ammonia gas

(b) Ca(OH)₂(aq) + NH₄NO₃ -> Ca(NO₃)₂ + 2H₂O + 2NH₃(g)

Practical 5 by Aloysius , Yu heng, Jia hao and de xin

Conclusion

1. A dilute acid and a carbonate forms carbon dioxide gas

2. Dilute acid + carbonate--> salt+ water+ carbon dioxide

3.

4. Use limewater to test for carbon dioxide released during the reaction between a dilute acid and carbonate. If the gas is carbon dioxide, white precipitate will be formed in the limewater.

5a. carbon dioxide is acidic

5b. Bubble the sample through a delivery tube into a test tube of alkaline, as carbon dioxide is acidic, the alkaline will neutralise the gas.

Exercise

Practical 5 by mervin, ethan, ryan, bohan

Observations:

Observation when carbonate is added to acid: Effervescene(bubbling) occurs

Effect of gas on limewater: Forms a white precipitate

Damp litmus paper: Red litmus-turns blue

Blue litmus-turns red

Conclusion

1) Effervescene occurs and carbon dioxide, water and salt is produced

2) Acid+carbonate-> salt+carbon dioxide+water

3) The salt produced is different

Explanation:

The reactants are different, thus it would produce a difference salt product

4) Bubble gas in to a beaker of limewater and see if a white precipitate forms. If it forms, it is carbon dioxide.

5a) Carbon dioxide is acidic.

Exercise:

2) na2co3+2hcl->2nacl+h2o+co2
3)potassium carbonate+hydrocho ...->potassium chloride+carbon dioxide+water
k2o3+2hcl->2kcl+h20+co2
4) calcium carbonate+nitric acid->calcium nitrate+carbon dioxide+water
2hno3 (aq) +caco3(s)=Ca(no3)2(s)+h2o(l)+co2(g)
5)sodium carbonate+nitric acid->carbonic acid+sodium nitrate
2hno3+na2co3->h2co3+2nano3
6)potassium carbonate+nitricacid->postaassium nitrate+carbon dioxide+water
na2co3+h2so4->na2so4+h20+co2
9)potassiumcarbonate+sulfuric acid->carbonic acid+potassium sulfate
k2co3+2so4->h2co3+k2so4
10)sodium carbonate+ethanoic acid->sodium ethanoate+carbon dioxoide+water
c02h(aq)+na2co3(s)->2ch3co2na(aq)+co2(g)+h20(l)
11)potassium carbonate+ethanoic acid->potassium ethanoate+water
ch3co2h(aq)+koh(aq)->ch3co2k(aq)+h2o(l)

Pratical 2P08 Preparation of soluble and insoluble salts

By Zhong Zhi (8) , Kenneth (16), Loh Jia Sheng (24) and Tan Ye Kai (32)

There are certain questions that we are not sure of, so there may be a few blanks

Part I
Procedure:
2)
Observations: copper sulfate crystals and water are formed
3)
Colour of filtrate: colourless
Colour of residue: blue
Name of filtrate: water
Name of residue: copper sulfate

1. CuO (s) + H2SO4 --> CuSO4 + H2O
2. Blue
3 (a)
Observations_________
Explanations________
(b)
Observations_________
Explanations________

Part II
Procedure
4.
Colour of filtrate: Blue
Colour of residue: White

Exercise
1.
Word equation: aqueous lead (II) nitrate + aqueous copper (II) sulfate --> Lead (II) sulfate
Chemical equation: ________________________-->_______________________
2.white precipitate is formed in a blue solution
3. lead (II) sulfate + sodiun sulfate or potassium sulfate