Sunday, October 9, 2011

GSI RESOURCES-TEMPAHAN BAJU

salam buat pembaca ( x lupe kpd follower) ^_*
             GSI tlah menubuhkn syarikat iaitu GSI RESOURCES. dimana korg boleh membuat tempahan baju ( design tersendiri ) kpd syarikat GSI. nanti sy akn upload beberape contoh design baju terbaru kami. @ korg boleh layari FB GSI. kalau berminat, korg boleh menutarakn soklan2 ( biar mencabar minda c kit erk? haha) korg dkat sini (comment).  k. stakat ini sje info kami pd hari nie.. ^_* wink2x..

LIRIK LAGU REMEMBER YOU/SITI NURHALIZA FT SEAN KINGSTON

If we never make it back
To what we used to be
I hope you know i tried to give you all of me
I don’t wanna wake up tomorrow
If our memories filled with sorrow
I’d rather smile when i remember you
If you find someone
That can love you right
I won’t stand in your way
I won’t even fight, no
I won’t forget
I’ll always remember you
*
Babygirl you are my darling
Felling you the hardest
Now my baby i’ve been missing you the longest
Found a new one to give your heart
To the way i acted i don’t blame you
But you always on my mind
Think about you all the time
And i’m wishing you were mine
Reminiscing all the time, when i had your love
When i had your love 
*
you forever be in my heart
You’ll always have my heart
You’re everything i wanted
Exactly what i needed
I see your heart has now moved on
Got me sitting here i’m singing sad songs
I’m a love you forever
Baby i forget you never
January to december always remember you
*
If you find someone
That can love you right
I won’t even fight,
No i won’t forget i’ll always remember you
Like the sun will rise
As the seasons change
I will walk through life
Til the very end, no i won’t regret
I’ll always remember you, remember you, rember you
I won’t forget i’ll always remember you
*
I don’t wanna wake up tomorrow
If our memories filled with sorrow
I’d rather smile when i remember you
If you find someone
That can love you right
I won’t stand in your way
I won’t even fight, no
I won’t forget i’ll always remember you
Like the sun will rise
As the seasons change
I will walk through life
Til the very end, no i won’t regret
I’ll always remember you
If you find someone
That can love you right
I won’t stand in your way
I won’t even fight, no

Wednesday, October 5, 2011

EXAMPLE LAB REPORT-SOLUBILITY AND MISCIBILITY

Introduction
            In general, SOLUBILITY is an ability of a substance to dissolve. In the process of dissolving, the substance which is being dissolved is called a solute and the substance in which the solute is dissolved is called a solvent. A mixture of solute and solvent is called a solution.
A chemist understands solubility as a measure. A chemist would say that:
SOLUBILITY is understood as a maximum amount of solute that dissolves in a solvent at so called equilibrium. In chemistry equilibrium is a state where reactants and products reach a balance - no more solute can be dissolved in the solvent in the set conditions (temperature, pressure). Such a solution is called a saturated solution.
In order for a solvent to dissolve a solute, the particles of the solvent must be able to separate the particles of the solute and occupy the intervening spaces.  Polar solvent molecules can effectively separate the molecules of other polar substances.  This happens when the positive end of a solvent molecule approaches the negative end of a solute molecule.  A force of attraction then exists between the two molecules.  The solute molecule is pulled into solution when the force overcomes the attractive force between the solute molecule and its neighboring solute molecule.  Ethyl alcohol and water are examples of polar substances that readily dissolve in each other.
The solubility of one substance dissolving in another is determined by the balance of intermolecular forces between the solvent and solute and the entropy change that accompanies the solution. Factors such as temperature and pressure will alter this balance, thus changing the solubility.
Temperature will affect solubility. If the solution process absorbs energy then the solubility will be increase as the temperature is increased. If the solution process releases energy then the solubility will decrease with increasing temperature.
Molecular size will affect the solubility. The larger the molecule or the higher its molecular weight the less soluble the substance will be. Larger molecules are more difficult to surround with solvent molecules in order to solvate the substance. In the case of organic compounds the amount of carbon "BRANCHING" will increase the solubility since more branching will reduce the size (or volume) of the molecule and make it easier to solvate the molecules with solvent.
The polarity of the solute and solvent molecules will affect the solubility. Generally polar solute molecules will dissolve in polar solvents and non-polar solute molecules will dissolve in non-polar solvents. The polar solute molecules have a positive and a negative end to the molecule. If it is polar solvent molecule, then positive ends of solvent molecules will attract negative ends of solute molecules. This is a type of intermolecular force known as dipole-dipole interaction. All molecules also have a type of intermolecular force much weaker than the other forces called London Dispersion forces where the positive nuclei of the atoms of the solute molecule will attract the negative electrons of the atoms of a solvent molecule. This gives the non-polar solvent a chance to solvate the solute molecules.
Some substances, like water and alcohol, can be mixed together and create a homogenous phase in any proportion. A solubility measure cannot be applied to such two substances. Such substances are called miscible. On the other hand if two substances cannot be mixed together (like water and oil), they are called immiscible.
If you add 50 mL of water to 50 mL of water you get 100 mL of water. Similarly, if you add 50 mL of ethanol (alcohol) to 50 mL of ethanol you get 100 mL of ethanol. But, if you mix 50 mL of water and 50 mL of ethanol you get approximately 96 mL of liquid, not 100 mL. Why?
The answer has to do with the different sizes of the water and ethanol molecules. Ethanol molecules are smaller than water molecules, so when the two liquids are mixed together the ethanol falls between the spaces left by the water.
            Iodine solution is more soluble in methylene chloride compared to water. The iodine is not very soluble in water because the water is polar solvent and the iodine is non-polar. The water is has a yellow colour from the iodine that is dissolved in it. When the methylene chloride is added to the water, it falls to the bottom of the funnel because it is denser than the water and iodine mixture. The methylene chloride is also not soluble because it is also non-polar. The methylene chloride extracts the iodine from the water. The methylene chloride dissolves the iodine preferentially because they are both non-polar. Likes dissolve likes. The iodine thus shows its true purple (pink) color in this solution.







Literature Review
There are many factors that can affect the solubility of solute in the solvent.
The first factor is temperature. Basically, solubility increases with temperature. It is the case for most of the solvents. The situation is though different for gases. With increase of the temperature they became less soluble in each other and in water, but more soluble in organic solvents. However, in this experiment, the temperature is fixed as it is carried out in the room temperature.
In most cases solutes dissolve in solvents that have a similar polarity. Chemists use a popular aphorism to describe this feature of solutes and solvents: "Like dissolves like". Non-polar solutes do not dissolve in polar solvents and polar solutes do not dissolve in non-polar solvents. In this experiment, we can conclude that distilled water is polar solvent, ethanol is partially polar solvent which contains polar and non-polar properties and hexane is non-polar solvent according to the solubility and miscibility of salts and liquids in them.
The larger the molecules of the solute are the larger is their molecular weight and their size. It is more difficult it is for solvent molecules to surround bigger molecules. If all of the above mentioned factors are excluded, a general rule can be found that larger particles are generally less soluble. If the pressure and temperature are the same than out of two solutes of the same polarity, the one with smaller particles is usually more soluble.
Stirring increases the speed of dissolving. Stirring does not have an effect on solubility of a substance, but everyone knows that if he puts sugar in his tea and does not stir, it will not dissolve. Actually, if we left the tea to stand for a long enough time, the sugar would dissolve. Stirring only increases the speed of the process - it increases move of the solvent what expose solute to fresh portions of it, thus enabling solubility. As molecules in liquid substances are in constant move, the process would take place anyway, but it would take more time. Thus, we are required to shake the mixtures vigorously to speed up the dissolving of salts and liquids.


There are several fundamental rules governing the miscibility of liquids in other liquids. First, the solubility of liquids in liquids increases with increasing temperature. Second, the more similar two compounds are in terms of polarity, the more likely that one is soluble in the other, i.e., polar compounds dissolve in polar compounds, and non-polar compounds dissolve in non-polar compounds. (Polar molecules dissolve in polar molecules because the dipole of one attracts the dipole end of the other.) Thus, benzene and carbon tetrachloride, being both non-polar, dissolve in each other, but neither will appreciably dissolve in water, which is polar.
Both alcohols and ethers with up to three or four carbons are miscible in water because the OH groups in these molecules form hydrogen bonds with the water molecules. Alcohols and ethers with higher molecular weights are not miscible in water, however, because the water molecules cannot completely surround those molecules. The molecule 1-heptanol, for example, consists of an alkyl chain of seven carbons and an OH group. The OH group forms hydrogen bonds with water molecules, but the alkyl portion of the molecule exerts no attraction on the water molecules. This part of the molecule is called hydrophobic, meaning water-hating. Because this part of the molecule cannot be surrounded by water, 1-heptanol is immiscible in water.
The methylene chloride forms bottom layer in the test tube due to it is denser than water and iodine dissolves in methylene chloride as they are both non-polar molecules.
Since Hexane and ethanol are very volatile and very flammable liquids. While working with them, absolutely no Bunsen burner flames should be in the nearby vicinity.









Experiment Objective
1.                  To become familiar with the components of a solution
2.                  To examine some of the terms and concepts associated with solutions.
3.                  To investigate solute and solvent interaction.
4.                  To learn to make inferences about the nature of substances based on their solubility or miscibility.


















Methodology
Materials
Test tube rack, 9 small test tubes, 3 rubber stoppers, spatula, hexane (C6H14), ethanol (C2H5OH), sodium chloride (NaCl), oxalic acid [(COOH)2], paraffin, cooking oil, methylene chloride (CH2Cl2), iodine (I2) or potassium iodide solution (KI)
Methods
A.         Solids in Liquids
1.                  Label nine test tubes as 1 to 9.
2.                  Fill test tube 1, 2 and 3 with distilled water (approximately ¼ full).
3.                  Fill test tube 4, 5 and 6 with ethanol (approximately ¼ full).
4.                  Fill test tube 7, 8 and 9 with hexane (approximately ¼ full).
5.                  Weigh 1.0 g sodium chloride and put it into test tube 1, 4 and 7, each.
6.                  Shake the mixture vigorously for about 30 seconds. Observe whether the solute dissolve in the solution or not. Record the data in Table 1.
7.                  Weigh 1.0 g oxalic acid and put it into test tube 2, 5 and 8, each. Repeat step 6.
8.                  Weigh 1.0 g paraffin and put in into test tube 3, 6 and 9, each. Repeat step 6.

CAUTION: Hexane and ethanol are very volatile and very flammable liquids. While working with them, absolutely no Bunsen burner flames should be in the nearby vicinity.





B.         Miscibility of Liquids
1.                  Add water, ethanol and hexane to 3 different test tubes (approximately ¼ full). Add 1 mL cooking oil to each of the test tubes. Froth gently to mix. Record your observations in Table 2.

C.         The Relative Solubility of a Solute in Two Solvents
1.                  Mix 2 ml methylene chloride and 4 ml water. Observe the relative position of each liquid, by noting the volume of each liquid. Shake the mixture for five seconds and allow the liquid to separate. What do you observe?

2.                  Add 2 drops of an iodine or potassium iodide solution to the test tube and note the colour of each layer and their intensities.

3.                  Shake the test tube gently for 20 seconds. Allow the liquids to separate and note again the colour of each layer.

4.                  Based on the relative intensity of the colours of the 2 layers, in which solvent is the iodine more soluble?








Result and Discussion
A.         Solids in Liquids          
Table 1
Solvent
Solute
Sodium chloride
Oxalic acid
Paraffin
Water
1) Soluble
2) Soluble
3) Insoluble
Ethanol
4) Insoluble
5) Soluble (Coldness is felt)
6) Insoluble
Hexane
7) Insoluble
8) Insoluble
9) Soluble

B.         Miscibility of Liquids
Table 2
Solvent
Observations
Water
Oil layer is formed on upper layer.
Ethanol
Oil layer is formed on bottom layer.
Hexane
Only one layer is formed. (Mixture of hexane and cooking oil)







C.         The Relative Solubility of a Solute in Two Solvents
STEP
OBSERVATIONS
1.
Two layers are formed where methylene chloride is denser than water.
2. Colour of the aqueous layer:
Colour of the methylene chloride layer:
Yellow
Colourless
3. Colour of the aqueous layer:
Colour of the methylene chloride layer:
Colourless
Pink

1.      Based on the relative intensity of the colours of the 2 layers, in which solvent is the iodine more soluble?
Methylene chloride.










Discussion
1)Using the solubility results obtained in this experiment, and knowing that sodium chloride is ionic and water is very polar, make inferences about the nature (polar or non-polar) of each of the following solutes and solvents.
Solutes:            Oxalic acid, paraffin
Solvents:          Ethanol, hexane



a - Solutes: Oxalic acid is a polar solute while paraffin is a non-polar solute.
b - Solvents: Ethanol is a polar solvent and hexane is a non-polar solvent.

The solubility of solid in liquids in part A depends on their nature. Their nature of chemical bond can contribute to attraction between molecules, hence contribute to solubility of that solid.        
 In part A, sodium chloride solid dissolve in water. This is because the nature of this solid. It is ionic compound. When dissolve in water the ions are stabilized by hydration which involve ion-dipole interaction. An ionic compound usually dissolves in polar molecule because they have dipole moment to solvate the ions. The non-polar molecules have lack dipole moment.
The term “like dissolve likes” is used to show that polar compound will dissolve in polar liquids and non-polar compound will dissolve in non-polar liquids. The same thing goes for oxalic acid and paraffin in water, ethanol and hexane. Thus, oxalic acid is a polar solute which dissolves in both water and ethanol (polar solvents) but not dissolve in hexane (non-polar solvent) and paraffin is just soluble in hexane.

2)      Infer the nature (polar or nonpolar) of cooking oil. Give reasons for your answer.

Cooking oil is a non-polar molecule. This is because cooking oil does not dissolve well in water and ethanol, which are polar molecules and non-polar system do not dissolve in polar ones.
 In part B, miscibility is a consequence of intermolecular forces. If two substances have same intermolecular forces, they are likely to be soluble in each other. Cooking oil and hexane are both non-polar molecules, hence have only dispersion force. The attraction between hexane and cooking oil is comparable in magnitude to that between hexane molecules and cooking oil molecules, thus they dissolve in each other. If two liquids are completely soluble in each other in all proportions they are said to be miscible and vice versa.
Exercise
1.      Explain the difference between miscible and soluble.
Miscibility means how completely two or more liquids dissolve in each other, miscibility is a consequence of intermolecular forces. If two substances have same intermolecular forces, they are likely to be soluble in each other. If two liquids are completely soluble in each other in all proportions they are said to be miscible and vice versa. While, solubilityis an ability of a substance to dissolve in a solvent. Their nature of chemical bonds can contribute to attraction between molecules, hence contribute to solubility of that solid.

2.      Characterize these compounds as soluble or insoluble in water
.           a.         CaCO3 – insoluble
            b.         ZnSO4   – soluble
            c.         Hg (NO3)2– soluble
            d.         NH4ClO4– partially soluble

3.                  While working in a machine shop you spilt a spot of grease on your shirt sleeve. In order to remove it, what would you use as a solvent with which to wash the spot? Water, ethanol or hexane? Explain why.
Grease consisting originally of a calcium, sodium or lithiumsoap jelly emulsified with liquid paraffin. Paraffin is nonpolar and is soluble in hexane which is also nonpolar. Hence, hexane should be used as a solvent with which to wash the spot of grease as the grease will dissolves into hexane leaving the shirt clean.

Conclusions & Recommendations
Based on the result of the experiment, sodium chloride soluble in water, it is insoluble in ethanol and hexane. Oxalic acid soluble in water and ethanol, it is insoluble in hexane and paraffin soluble in hexane, it is insoluble in water and ethanol.
Cooking oil is miscible with hexane; it is immiscible with water and cooking oil. Iodine is more soluble in methylene chloride.
During the experiment, we must absolutely no Bunsen burner flames should be in the nearby vicinity because hexane and ethanol are very volatile and very flammable liquids. 
















References
·         Chang, Raymond (2003). General Chemistry.3rded. New York: McGraw-Hill
·         Umland and Bellama (1999). General Chemistry. 3rd ed. Pacific Grove, CA: Brooks/Cole Publishing Company
·         http://www.answers.com/topic/oxalic-acid

BTW~~ memandangkan korg2 dh baca apekate appreciate my writing dgn klik ni ---> http://my.sharings.cc/gsict/share/GSCSHR  just one click! ^^ thank you! 

~INI EXAMPLE JER...tapi tolong jgn copy n paste ini punyer..hahaha slalu memang dh jd tradisi copy n paste ni. tolong erk..jdkn ia sbg rujukn jer.. ^_*~  jika adik2x junior nk contoh lab report yg lain, ckp jer..insyaALLAH wa bleh tolng.. WINK2X...

HOW TO MAKE SOLUTION ( CHEMICAL ENGINEERING )~ ACETIC ACID

                                                         
   








            CHEMICAL PREPARATION FOR 2.00 M Acetic acid                 
                                                         
     


                                                                                                                                              

 
       
       
       
       
       
       
       
       
       
density 2.1    
  0.011    
  60.05    
m1 0.367    
v1 #####   Measure ##### ml Acetic acid      Pour it into beaker that   Transfer the mixture into   Fill up the volumetric flask The chemical ready  
      using pipette           contain 125 ml of      250  ml volumetric flask with distilled water up to   for used      
                         distilled water & stirred it             line scale and shake it            
                    until the chemical fully mix                              
                                                         
      FIRST AID MEASURE   CHEMICAL PROPERTIES  
                                                         
        Contact with eye : Rinse immediately for at least 15 minutes.           Name : Acetic acid   
        Contact with skin : Wash affected areas with soap and water.         Sinonim : methane carboxylic acid; ethanoic acid  
        Inhale : Move to fresh air.                 Formula Structure : 0  
        Ingest : rinse mouth and drink 2-4 cupfuls of milk or water         Density : 2.1 g/cm3        
        Spillage :  N/A                     Molecular Weight : 60.05 mol/g          
        HAZARD : Corrosive                 Location : Store 2 rack G        
                                                         

Popular Posts

LAWAK MINGGU INI

Doktor: Encik kena ambil 3 sudu ubat ni setiap hari.
Pesakit: Eh! tak boleh la doktor.
Doktor: Kenapa?
Pesakit: Rumah saya ada dua sudu jer.

maaplah kalau x lawak..hihih =P

Contributors