experiment steps ...chemistry form 4 n 5Full description
Full description
Separation of contents of a ternary mixtureFull description
MAH CET Sample Paper-3 (Chemistry-paper)Full description
chem format for writing your pre labs in your notebook.Full description
Suggested solutions for 2017 H2 Chemistry Paper 3
Final Examination Chemistry Form 4
CSEC - Chemistry - May June 1995 Paper 3
ISC 2011 Chemistry PaperFull description
Chemistry Olympiad 2008 (Paper)
Chemistry paper 1 2009.docFull description
ICAS writing Paper H
Chemistry Olympiad 2009 (Paper)
report writing uitmFull description
SgtMaj Thielen from Regimental Combat Team 5 put together a guide for the regiment's officers on writing effective fitness reports on their subordinate leaders. The guide provides a light ov…Full description
Descripción completa
1
Chemistry Paper 3 (Section B - Report Writing)
1. Aim 2. Variables 3. Hypothesis 4. Apparatus & Materials 5. Procedure of experiment 6. Tabulation of data
a) Experiment 1: The melting and freezing points of naphthalene
i)
Aim = To determine the melting/ freezing points of naphthalene when heated/cooled.
ii)
iii)
Variable Manipulated v:
The time of heating/ cooling
Responding v:
The temperature of naphthalene
Constant v:
The volume of water bath used
Hypothesis = The longer the time taken to heat/cool, the higher/lower the temperature of naphthalene.
iv)
Materials = Naphthalene powder, water Apparatus = Boiling tube, retort stand with clamp, thermometer, stopwatch, Bunsen burner, tripod stand, wire gauze, beaker, spatula, asbestos sheet
1
2
v)
Procedure of experiment
1. A boiling tube is filled to about 5cm high with naphthalene powder. 2. The boiling tube is half-immersed in a beaker half-filled with so water so that naphthalene powder in the boiling tube is totally immersed in water. 3. A thermometer is put into the naphthalene powder in the boiling tube. 4. The water in the beaker is heated gently and steadily. 5. The naphthalene powder is stirred continuously with a thermometer throughout heating to get a uniform temperature. 6. While stirring, the temperature of naphthalene is recorded every o
o
half a minute from the temperature of 60 C to 90 C. vi)
Tabulation of data Can be used for both heating/cooling of naphthalene Time (s) 0 30 60 90 120 150 180 210
Temperature (oC)
2
3
b) Experiment 2: Reaction of alkali metals with water (Group 1 Elements)
I.
Aim
= To determine the reaction of alkali metals with water. II.
III.
Variable Manipulated v:
The alkali metals used
Responding v:
The reactivity of the metal with water
Constant v:
The size of alkali metal / the temperature of water
Hypothesis = The lower the position in Group 1 elements in the Periodic Table, the higher the reactivity of the elements with water.
IV.
Materials = Small pieces of lithium, sodium and potassium metals, and basin filled with water, filter paper and red litmus paper Apparatus = Pen knife and goggles
V.
Procedure of experiment
* Draw three of the same diagram and label each with lithium, sodium & potassium 3
4
1. A basin is half filled with water. 2. A piece of lithium is cut with a pen knife 3. The oil on its surface is dried with a filter paper. 4. The lithium is dropped into the water in the trough. 5. The reactivity of lithium with water is observed and recorded. 6. The water in the trough is then tested with a piece of red litmus paper when the reaction stops. 7. The experiment is repeated by using sodium and potassium of the same size. VI.
Tabulation of data Metal
Observation
Lithium Sodium Potassium
4
5
c) Experiment 3: The empirical formula of copper oxide
i.
Aim = To determine the empirical formula of copper oxide
ii.
iii.
Variable Manipulated v:
The mass of copper oxide
Responding v:
The mass of copper formed
Constant v:
The excess of hydrogen gas
Hypothesis = The empirical formula of copper (II) oxide can be determined by finding out the mass of copper and oxygen in a sample of copper (II) oxide.
iv.
Materials = Copper oxide powder, dry hydrogen gas Apparatus = Porcelain dish, combustion tube and electronic balance
v.
Procedure of experiment
1. The combustion tube with a porcelain dish is weighed. The weight is recorded. 2. A spatula of copper oxide powder is placed in the porcelain dish. The combustion tube with its contents is weighed again. The weight is recorded. 3. Dry hydrogen gas is passed through the tube for a few minutes to expell all the air.
5
6
4. The copper oxide is than heated strongly and the hydrogen gas passing through the end of the combustion tube is llit. 5. When all the copper oxide is reduced to copper metal (the black copper oxide has all become brown), heating is stopped. 6. A continous stream of hydrogen gas is allowed to pass through the tube until it is cooled. 7. The combustion tube with the contents is weighted. The weight is recorded. 8. The heating, cooling and weighing process is repeated until a constant weight is obtained. vi.
