Displaying 11 to 20 of 255 Questions. You are on Page No. 2 of total 26 pages
Question: What is the process used to separate the different components of oil?
Correct Answer This process is based on the fact that the different components of oil have different boiling points. In this process, oil is heated in a furnace to 400 degree Celsius(752 F) and it vapourises. The vapours are introduced into a tall fractionating column. There the component vapours condense one by one at different heights. The vapours with lower boiling points condense at the top and those with higher boiling points condense near the bottom. The various fractions are then collected from the column. Some of them are - Petroleum gas, gasoline, kerosene, diesel, fuel oil, lubricating oil, wax and asphalt.
Question: What is the main constituent of coal gas?
Correct Answer By the destructive distillation of coal, we can obtain coal gas, coal tar and ammonia. Coke is left as a residue. Coal gas contains methane, carbon monoxide and hydrogen. Since all the three are combustible, coal gas is a good fuel with a high calorific value.
Question: Coal is formed due to the process of...?
Correct Answer About 300 million years ago, in a period of history called the Carboniferous Era, huge swamp forests were buried deep in the Earth's crust due to earth movements. Extreme pressure and temperature converted their biomass into coal. This process is called Carbonization.
Question: Which of these has the highest calorific value?
Correct Answer One gram of Hydrogen releases about 150 kilojoules of energy, almost thrice as much as methane does. I'm sure you know about liquid hydrogen! Coal comes second followed by wood having a low calorific value of 17 kJ/g.
Question: What is the main component of biogas and natural gas?
Correct Answer Biogas also contains hydrogen, carbon dioxide and hydrogen sulphide. In fact it contains about 65 percent of CH4. Natural gas contains small amounts of ethane and propane also. Both the gases are clean fuels since they cause little or no pollution. The importance of these gases is increasing at a fast rate for both rural and urban usage.
Question: Heating fuels in the absence of air is called 'Destructive Distillation', as it 'destroys' it to form simpler substances. What do we get when we do the same to wood?
Correct Answer Besides charcoal, tar and acetic acid, wood gas and methyl alcohol are also formed. Charcoal is the residue and the others are volatile. Charcoal is an ideal fuel but its use is widely discouraged because thousands of trees are felled for this.
Question: If you wanted to lighten your hair at home, what is the active ingredient in the dye preparation that will lighten your hair?
Correct Answer Although there are other substances that will lighten hair, hydrogen peroxide (chemical formula H202 - looks like water, but very different!) is still very common in hair dye preparations (especially ones designed to turn you into a blond). The hydrogen peroxide in the preparation acts as a bleach and strips the hair shaft of its colour; the amount of hydrogen peroxide you use on your hair will determine how "blond" you go. Hydrogen peroxide is actually not a very nice chemical at all (the materials safety data sheet for hydrogen peroxide says it can cause serious burns), so wear gloves and be careful when using it!
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Question: "Antifreeze" is used in car radiators to stop the liquid that cools the engine from, well, freezing when it gets cold outside. Water is one component of antifreeze; what is the other main component?
Correct Answer Antifreeze is an ethylene glycol-water mixture. Water is an excellent conductor of heat, which is why it's used in car radiators, but it freezes at too high a temperature to be used on its own. It's mixed with ethylene glycol to lower the freezing point - a phenomenon known as freezing point depression (this is the same phenomenon that makes pouring salt onto snow effective in making it melt faster). The ethylene glycol molecules act as "impurities" in the water, meaning that when the temperature gets low, the water can no longer easily form the regular 3-dimensional solid lattice it does when it freezes, so the temperature must be taken lower to freeze the mixture. A 50:50 mixture of water and ethylene glycol freezes at -37C (-35F) - very comforting to know when you're driving in a snowstorm! See http://auto.howstuffworks.com/cooling-system3.htm for more information.
Question: Aspirin can be found in many household medicine cabinets. But what is it chemically?
Correct Answer A tablet of aspirin contains pure acetylsalicylic acid and a bit of binder to help hold the tablet together. Aspirin is a remarkable substance in that it can act as an analgesic (to relieve pain), an antipyretic (to lower fever) _and_ an anti-inflammatory agent (to reduce inflammation). It was first synthesised in 1853 and was accepted into widespread pharmaceutical use at the end of the 19th century. The parent compound salicylic acid was also known as spiraeic acid, and the name "aspirin" was derived by taking the "a" from "acetyl" and combining it with "spir" taken from the acid's name. Aspirin can cause irritation of the stomach, and due to this, its popularity has declined recently (in favour of other medications such as paracetamol, ibuprofen and acetaminophen) but it is still the most widely used drug for the treatment of illness or injury.