Ending Post ! : D

Yeahh , all research on substances had been done .
We hope that we will get high marks on this holiday assignment !

Now, lets watch videos on 'Experimental Chemistry' !
by logging in to http://www.woodlandssec.sg : D

Signing Off ..

Abdul

Shah

Firdaus

Sodium Hydroxide

Sodium hydroxide (NaOH), also known as caustic soda, is an extremely caustic metallic base. It is used in many industries, mostly as a strong chemical base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a drain cleaner. Worldwide production in 1998 was around 45 million tonnes. Sodium hydroxide is a common base in chemical laboratories.

Pure sodium hydroxide is a white solid; available in pellets, flakes, granules and as a 50% saturated solution. It readily absorbs water from the air, so it should be stored in an airtight container. It is very soluble in water with liberation of heat. It also dissolves in ethanol and methanol, though it exhibits lower solubility in these solvents than does potassium hydroxide. A sodium hydroxide solution will leave a yellow stain on fabric and paper.


Two of the more common household products containing sodium hydroxide are drain cleaners and oven cleaners. When most pipes are clogged it is with a combination of fats and grease. Cleaners that contain sodium hydroxide (either as a solid or already dissolved in water) convert the fats to soap, which dissolves in water. In addition, when sodium hydroxide dissolves in water a great deal of heat is given off. This heat helps to melt the clog. Sodium hydroxide is very damaging to human tissue (especially eyes). If a large amount of solid drain cleaner is added to a clogged drain, the heat produced can actually boil the water, leading to a splash in the eyes of a solution caustic enough to cause blindness. Some drain cleaners also contain small pieces of aluminum metal. Aluminum reacts with sodium hydroxide in water to produce hydrogen gas. The bubbles of hydrogen gas help to agitate the mixture, helping to dislodge the clog.
Oven cleaners work by converting built up grease (fats and oils) into soap, which can then be dissolved and wiped off with a wet sponge.

These are products that can be found in the supermarket; and it contains sodium hydroxide. The picture on the left is the a bottle of drain cleaner, while the second picture is another bottle of oven cleaner. Both contains sodium hydroxide that pumps up to do their task.

Citric Acid

Citric acid is a weak organic acid. At room temperature, citric acid is a white crystalline powder. It is a natural preservative and is also used to add an acidic, or sour, taste to foods and soft drinks. Citric acid exists in greater than trace amounts in a variety of fruits and vegetables, most notably citrus fruits. Lemons and limes have particularly high concentrations of the acid; it can constitute as much as 8% of the dry weight of these fruits. Within species, these values vary depending on the cultivar and the circumstances in which the fruit was grown. Citric acid has been used as an additive to soft drinks, beer, and fizzy water, and occurs naturally in many juices.

As a food additive, citric acid is used as a flavoring and preservative in food and beverages, especially soft drinks. Citrate salts of various metals are used to deliver those minerals in a biologically available form in many dietary supplements. The buffering properties of citrates are used to control pH in household cleaners and pharmaceuticals.

Citric acid is the active ingredient in some bathroom and kitchen cleaning solutions. A solution with a 6% concentration of citric acid will remove hard water stains from glass without scrubbing. In industry it is used to dissolve rust from steel.
Citric acid is commonly employed in wine production as a substitute or improver where fruits containing little or no natural acidity are used. It is mostly used for inexpensive wines due to its low cost of production
Citric acid can be used in food coloring to balance the pH level of the normally basic dye.

Contact with dry citric acid or with concentrated solutions can result in skin and eye irritation, so protective clothing should be worn when handling these materials. Contact to the eyes can cause a burning sensation, and may cause blindness with prolonged exposure in extremely high concentrations. Sometimes a high concentration of citric acid can damage hair and bleach it.

These are juices that can be found at the supermarket. Both bottle of juices contains citric acid. The picture on the left is Minute Maid Orange Juice, while on the right is the Minute Maid Lemonade. Boh are made for refreshing goodness.

Ammonium Sulphate

Ammonium sulfate, (NH4)2SO4, is an inorganic salt with a number of commercial uses. It is a brownish-grey to white crystalline salt, commonly use in soil fertilizer. It contains 21% nitrogen as ammonium cations, and 24% sulfur as sulfate anions. In fertilizer the purpose of the sulfate is to reduce the soil pH.

It is used largely as an artificial fertilizer for alkaline soils. Alkaline, soils are clay soils with high pH (> 9), a poor soil structure and a low infiltration capacity. In the soil, the sulfate ion is released and forms an acid sulphate, lowering the pH balance of the soil, while contributing essential nitrogen for plant growth.

It is also used as an agricultural spray that prevents or removes water soluble insecticides, herbicides, and fungicides. There it functions to bind iron and calcium cations that are present in both well water and plant cells.

It is also used in the preparation of other ammonium salts.

These are 2 products. The picture on the left shows a bottle of Scotts Agricultural Sprays, while the picture on the right shows Scotts Fertilizers. Both product contains ammonium sulphate; and these product can be found at supermarkets. The product that contains ammonium sulphate are usually products that are meant for plantation purposes. They are not edible as they are treatment products.

Mono-Sodium Glutamate

The Ajinomoto company was formed to manufacture and market MSG in Japan; the name 'Aji no moto' translates to "essence of taste". It was introduced to the United States in 1947 as Ac'cent flavor enhancer. In its pure form, it appears as a white crystalline powder which rapidly dissociates into sodium cations and glutamate anions on contact with water.

MSG is normally obtained by the fermentation of carbohydrates and by using bacterial or yeast species from genera such as Brevibacterium. Brevibacterium is a genus of bacteria which are Gram-positive soil organisms. It is suitable for us to consume; but when we consume too much of it, it will cause side effects.

MSG side effects can result in:

• Numbness
• Burning sensation
• Tingling
• Facial pressure or tightness
• Chest pain
• Headache
• Nausea
• Rapid heartbeat
• Drowsiness
• Weakness
• Difficulty breathing for asthmatics

These are 2 product that contains mono-sodium glutamate. The picture on the left shows a bottle of Maggie Oyster Sauce, while the picture on the right shows a cup of Maggie Cup Noodles. Both product can be found in the supermarket .

Sodium Chloride

Sodium chloride, is also known as salts, common salts, table salts, or halite, is an ionic compound with the formula NaCl. The second picture on the left shows a halite. Halite is the mineral form of sodium chloride, NaCl, commonly known as rock salt. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluids of many multicellular organisms. Extracellular fluids usually denotes all body fluids outside the cell (sweats). As the major ingredient in edible salts, is commonly used as a condiment and food preservative. A condiment is a type of sauce, of seasoning added to the particular food.

Uses of salt in cooking, salt is used in many applications, from manufacturing pulp and paper, to setting dyes in textiles and fabric, to producing soaps, detergent, and other bath products. It is the major source of industrial chlorine and sodium hydroxide, and used in almost every industry.

Salting in an effective mathod of food preservation historically; as it draws water out of bacteria through osmotic pressure, preventing them from reproducing and causing food to spoil. Osmotic pressure applied by a solution to prevent the inwards flow of water across a semipermeable membrane. Even though more effective desiccants (silica gel) are available, few are safe for humans to ingest .

During our search at the supermarket, we found out that both product on the left contains sodium chloride. The first picture shows a product called 'Sunny 1 Enriched White Bread' while the second shows another product called 'Hinode Lower Sodium Salts' . These are products which are commonly consumed .

at the supermarket entrance !

the supermarket entrance !
three of us at the entrance : )

shah ; D abdul : ) firdaus o.0

Chemistry Holiday Assignment

We are suppose to choose 5 substances from the list which is given .
We choose 3 substance which is under salt and the other 2 substance
are from base and acid each . We had chosen ;

1. Sodium Chloride (salts)
2. Mono-sodium Glutamate (salts)
3. Ammonium Sulphate (salts)
4. Citric Acid (acid)
5. Sodium Hydroxide (base)

We will have to do research on all the selected substances , and have to make a visit to the supermarket to search for products that contain the above substances . But before that , we will have to take a photo of us at the supermarket entrance .