We can collect gases in
4 ways :
1- Downwards into a testube or a gas jar , this is used for gases which denser than air .
2- Upwards into a testube are a gas jar , this used to collect gases which less dense than air and are soluble in water .
3- Over water , - to collect gases which are less dense than air and are insoluble in water- or to collect gases which are having the same dense like air and are insoluble in water .
4- In a gas syringe , a gas syringe is used to collect the gas and to measure the volume of the gas collected .
2- Normal test – pure water boils at 100 degrees Celsius
Friday, November 27, 2009
Sunday, November 22, 2009
TITRATION OF UNKNOWN ACID
Titration of an Unknown (if done as per your instructor's directions)
1. Obtain an unknown solid and record its number.
2. Weigh out 0.1-0.2 g and place it in an Erlenmeyer flask.
3. Dissolve the acid in about 20 mL boiled distilled water.
4. Add two drops of the phenolphthalein indicator.
5. Titrate to the pale pink endpoint.6. Carry out at least two titrations; repeat until two consecutive values for equivalent weight of the acid differ by no more than 1%.
1. Obtain an unknown solid and record its number.
2. Weigh out 0.1-0.2 g and place it in an Erlenmeyer flask.
3. Dissolve the acid in about 20 mL boiled distilled water.
4. Add two drops of the phenolphthalein indicator.
5. Titrate to the pale pink endpoint.6. Carry out at least two titrations; repeat until two consecutive values for equivalent weight of the acid differ by no more than 1%.
standardization ഓഫ് NaoH
Standardization of NaOH1.
Clean a buret and rinse it with the NaOHyou just prepared.
2. Fill the buret with the NaOH.
3. Weigh a clean dry beaker on a balance.
4. Weigh out 0.2 - 0.4 g of KHC8H4O4 and place it in the beaker you just weighed. Make sure you record the weights!
5. Pour the acid into an Erlenmeyer flask; use a stream of water from the wash bottle to complete the transfer.
6. Dissolve this acid in about 20 mL of the boiled distilled water.
7. Add two drops of the phenolphthalein indicator to the flask.
8. Read the buret and record the initial volume making sure there is not a drop on the tip of the buret; if there is, use an extra beaker to get rid of this drop by touching the side of the beaker to the tip of the buret.
9. Place the Erlenmeyer flask under the buret, and place a piece of white paper under it.
10. Position the tip of the buret so it is just beneath the rim of the flask.
11. Add several mL (probably no more than ten) of base solution (NaOH) rapidly with constant swirling.
12. Close buret stopcock to only allow a rapid stream of drops and swirl; at the site where the solution in the buret drops in the acid solution, you will see a pink color, which will disappear
13. When the pink color lingers longer, close the stopcock on the buret more so that you add a drop and swirl until the color changes before adding another drop.
14. Occasionally wash down the sides of the flask with the wash bottle.
15. Near the end point you will want to use partial drops. To do this, open the stopcock so that a drop forms on the tip of the buret. Close the stopcock and use a stream of water from the water bottle to wash the droplet into the sol.
16. Keep adding base until a very light pink color persists for at least 20 seconds.
17. Record the final buret reading.18. Repeat this procedure at least two more times; repeat the titrations until two values for molarity differ by no more than 1% C.
Clean a buret and rinse it with the NaOHyou just prepared.
2. Fill the buret with the NaOH.
3. Weigh a clean dry beaker on a balance.
4. Weigh out 0.2 - 0.4 g of KHC8H4O4 and place it in the beaker you just weighed. Make sure you record the weights!
5. Pour the acid into an Erlenmeyer flask; use a stream of water from the wash bottle to complete the transfer.
6. Dissolve this acid in about 20 mL of the boiled distilled water.
7. Add two drops of the phenolphthalein indicator to the flask.
8. Read the buret and record the initial volume making sure there is not a drop on the tip of the buret; if there is, use an extra beaker to get rid of this drop by touching the side of the beaker to the tip of the buret.
9. Place the Erlenmeyer flask under the buret, and place a piece of white paper under it.
10. Position the tip of the buret so it is just beneath the rim of the flask.
11. Add several mL (probably no more than ten) of base solution (NaOH) rapidly with constant swirling.
12. Close buret stopcock to only allow a rapid stream of drops and swirl; at the site where the solution in the buret drops in the acid solution, you will see a pink color, which will disappear
13. When the pink color lingers longer, close the stopcock on the buret more so that you add a drop and swirl until the color changes before adding another drop.
14. Occasionally wash down the sides of the flask with the wash bottle.
15. Near the end point you will want to use partial drops. To do this, open the stopcock so that a drop forms on the tip of the buret. Close the stopcock and use a stream of water from the water bottle to wash the droplet into the sol.
16. Keep adding base until a very light pink color persists for at least 20 seconds.
17. Record the final buret reading.18. Repeat this procedure at least two more times; repeat the titrations until two values for molarity differ by no more than 1% C.
Wednesday, November 18, 2009
Metallic bonding work sheet IGCSE
1. DESCRIBE METTALIC BONDING
2. WHY METALS ARE MALLIABLE?
3. DEFINE ALLOYS? GIVE EX .
4. WHY ALLOYS ARE HARD IN NATURE?
2. WHY METALS ARE MALLIABLE?
3. DEFINE ALLOYS? GIVE EX .
4. WHY ALLOYS ARE HARD IN NATURE?
IONIC BONDING / WORK SHEET / IGCSE / GCSE / CHEMISTRY
1.Draw the dot and cross diagram dor the following
Calcium oxide
Magnesiumm chloride
Lithum chloride
2. Give the properties of ionic com pounds
3. sodium chloride conduct electricity in liquid state . why/
4. sodium chloride do not conduct electricity in solid state . why/
Calcium oxide
Magnesiumm chloride
Lithum chloride
2. Give the properties of ionic com pounds
3. sodium chloride conduct electricity in liquid state . why/
4. sodium chloride do not conduct electricity in solid state . why/
The Noble Gases- igcse / gcse/ o level
1.What is the Group Number of the Noble Gases?
2.What does Monatomic mean?
3.Going down the Group, do the Noble Gases have a Higher Boiling Point?
4.Give one Use of Helium?
5.Give one Use of Neon?
6.Give one Use of Argon?
2.What does Monatomic mean?
3.Going down the Group, do the Noble Gases have a Higher Boiling Point?
4.Give one Use of Helium?
5.Give one Use of Neon?
6.Give one Use of Argon?
The Halogens- igcse/ gcse/ o level
The Halogens- igcse/ gcse/ o level
1.What is the Group Number of the Halogens?
2.What does Diatomic mean? 37.What Colour is Chlorine?
3.What Colour is Bromine?
4.Is Iodine a Liquid?
5.Going down the Group, do the Halogens become More Reactive?
6.Going down the Group, do the Halogens have a Higher Boiling Point?
7.Write the Balanced Equation for the reaction between Aluminium and Chlorine.
8.Write the Balanced Equation for the reaction of Chlorine with Potassium Iodide.
9.Write the Ionic Equation for the reaction of Chlorine with Potassium Iodide.
10.Give one Use of Fluoride?
11.Give one Use of Chlorine? 47Give one Use of Bromide?
12.What does Hydrogen Chloride make when it is Dissolved in Water?
13.How is Hydrogen Chloride Safely Dissolved in Water?
1.What is the Group Number of the Halogens?
2.What does Diatomic mean? 37.What Colour is Chlorine?
3.What Colour is Bromine?
4.Is Iodine a Liquid?
5.Going down the Group, do the Halogens become More Reactive?
6.Going down the Group, do the Halogens have a Higher Boiling Point?
7.Write the Balanced Equation for the reaction between Aluminium and Chlorine.
8.Write the Balanced Equation for the reaction of Chlorine with Potassium Iodide.
9.Write the Ionic Equation for the reaction of Chlorine with Potassium Iodide.
10.Give one Use of Fluoride?
11.Give one Use of Chlorine? 47Give one Use of Bromide?
12.What does Hydrogen Chloride make when it is Dissolved in Water?
13.How is Hydrogen Chloride Safely Dissolved in Water?
The Transition Metals- igcse/ gcse/olevel
1.Where do you find the Transition Metals in the Periodic Table?
2.What is their Group Number?
3.Do the Transition Metals Conduct Electricity?
4.Do the Transition Metals form Coloured Compounds?
5.Give one Use of Copper?
6.Give one Example of a Transition Metal Used as a Catalyst.
2.What is their Group Number?
3.Do the Transition Metals Conduct Electricity?
4.Do the Transition Metals form Coloured Compounds?
5.Give one Use of Copper?
6.Give one Example of a Transition Metal Used as a Catalyst.
Electrolysis of Sodium Chloride in Water
1.What is Brine?
2.Which Gas is given off at the Cathode?
3.Which Gas is given off at the Anode?
4.Give the Ionic Equation for the Gas given off at the Anode.
5Why don't you get Sodium Metal at the Cathode?
6.What Substance is left in Solution after Electrolysis?
7.Give one Use of this Substance?
2.Which Gas is given off at the Cathode?
3.Which Gas is given off at the Anode?
4.Give the Ionic Equation for the Gas given off at the Anode.
5Why don't you get Sodium Metal at the Cathode?
6.What Substance is left in Solution after Electrolysis?
7.Give one Use of this Substance?
The Alkali Metals- igcse/ gcse /olevel
1.What is the Group Number of the Alkali Metals?
2.Why are the Alkali Metals stored under oil?
3.Give two Properties of the Alkali Metals?
4.Going down the Group, do the Alkali Metals become More Reactive?
5.Write the Word Equation for the reaction when Potassium burns in Air.
6.What Colour is the Flame from Potassium?
7.Write the Balanced Equation for the reaction when Potassium burns in Air.
8.Write the Balanced Equation for the reaction between Sodium and Water.
9.Write two things you would See in the reaction between Sodium and Water.
10.Write the Balanced Equation for the reaction between Lithium and Chlorine.
11.Give one Property of an Alkali Metal Compound?
12.Give one Use of Sodium Chloride?
13.Give one Use of Sodium Carbonate?
2.Why are the Alkali Metals stored under oil?
3.Give two Properties of the Alkali Metals?
4.Going down the Group, do the Alkali Metals become More Reactive?
5.Write the Word Equation for the reaction when Potassium burns in Air.
6.What Colour is the Flame from Potassium?
7.Write the Balanced Equation for the reaction when Potassium burns in Air.
8.Write the Balanced Equation for the reaction between Sodium and Water.
9.Write two things you would See in the reaction between Sodium and Water.
10.Write the Balanced Equation for the reaction between Lithium and Chlorine.
11.Give one Property of an Alkali Metal Compound?
12.Give one Use of Sodium Chloride?
13.Give one Use of Sodium Carbonate?
Preparation of NaOH solution
InstructionsA.
Preparation of NaOH സോലുറേന്
1. Measure about 500 mL of distilled water and boil it for about five minutes.
2. Allow the beaker to cool enough so you can pick it up with a towel.
3. Using a graduated cylinder, measure 290 mL of this water into a large flask.
4. Add 10 mL of 3M NaOH to this water.CAUTION! NaOH IS CORROSIVE!!!!!!! If you spill any on yourself, wash it off immediately!!!!5. Stopper the flask, making sure not to let the stopper come in contact with the solution.6. Swirl the flask to mix the NaOH and water.7. Pour the rest of the water you boiled into a wash bottle. You can use this later to dissolve the acid sample and wash down the sides of the flask during the titration.B.
Preparation of NaOH സോലുറേന്
1. Measure about 500 mL of distilled water and boil it for about five minutes.
2. Allow the beaker to cool enough so you can pick it up with a towel.
3. Using a graduated cylinder, measure 290 mL of this water into a large flask.
4. Add 10 mL of 3M NaOH to this water.CAUTION! NaOH IS CORROSIVE!!!!!!! If you spill any on yourself, wash it off immediately!!!!5. Stopper the flask, making sure not to let the stopper come in contact with the solution.6. Swirl the flask to mix the NaOH and water.7. Pour the rest of the water you boiled into a wash bottle. You can use this later to dissolve the acid sample and wash down the sides of the flask during the titration.B.
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