Thursday, August 30, 2018
Tuesday, August 28, 2018
Engineering chemistry question
1.Hydrogenation is conversion of unsaturated acid groups into the saturated one by catalyst
a) Ti
b) Pb
c) Ni
d) Sn
Answer: c
Explanation: Hydrogenation is conversion of unsaturated acid groups into the saturated one by metal Nickel (Ni) catalyst.
2.Vegetable ghee is manufactured by
a) Saponification
b) Hydrogenation
c) Oxidation polymerisation
d) Reduction polymerisation
Answer: b
Explanation: Vegetable ghee is manufactured by hydrogenation. But due to the trans fatty acids dilemma, partial hydrogenation is no longer viable
3. Hydrogenolysis is a reaction which leads to the reduction products of
a) Aldehyde
b) Ketone
c) Alcohol
d) Ester
Answer: c
Explanation: Hydrogenolysis is a reaction which leads to the formation of glycerol and reduction products of alcohol.
Thursday, August 23, 2018
Biochemistry quiz
Q.1 Main function of insulin hormone is to
A. increase glycogen in liverB. decrease glycogen in liver
C. increase blood sugar
A. reducing agent
B. oxidizing agent
C. oxidizing and reducing agent both
D. none of the above
Answer: Option A
Q.3 A deficiency of thiamin produces the disease known as
A. beri-beri
B. scurvy
C. cataract
D. anemia
Answer: Option A
Friday, August 17, 2018
Basic quizzes
Q.1 An _______ bond is a bond in which electrons are transferred.
A.Covalent
Q.2 Gold is an example of a ______.
A.Molecule
B.Element
C.Atom
Q.3 The water molecule is _________, because there is an uneven distribution of electron within the molecule.
A.Uneven
B.Weird
C.Polar
A.Covalent
B.Ionic
C.Double
Answer:-Ionic
A.Molecule
B.Element
C.Atom
D.Covalent bond
Answer:-Element
Q.3 The water molecule is _________, because there is an uneven distribution of electron within the molecule.
A.Uneven
B.Weird
C.Polar
D.Strange
Answer:-Polar
Wednesday, August 15, 2018
Basic quiz
Suppose the elements X and Y combine to form two compounds XY2 and X3Y2. When 0.1 mole of XY2 weighs 10 g and 0.05 mole of X3Y2 weighs 9 g, the atomic weights of X and Y are [NEET 2016]
(A) 40, 30
(B) 60, 40
(C) 20, 30
(D) 30, 20
(A) 40, 30
(B) 60, 40
(C) 20, 30
(D) 30, 20
Tuesday, August 14, 2018
What Common Chemicals Shouldn't Be Mixed?
Some of the common chemicals found in your home shouldn't be mixed together. It's one thing to say "don't mix bleach with ammonia," but it's not always easy to know what products contain these two chemicals. Here are some household products you may have around the home that shouldn't be combined.
This mixture can result in toxic, potentially deadly fumes.
Vinegar is a type of acid.
Toxic chlorine vapor is produced. Don't mix chlorine bleach with any acid.
This is toxic. Potentially lethal vapors are produced. The main danger comes from chloramine vapors.
Don't mix different cleaners together. They may react violently, produce toxins, or become ineffective.
Acids and bases (alkalis) can react violently, presenting a splash hazard. Acids and bases are caustic and may cause chemical burns.
Don't mix disinfectants with 'quaternary ammonia' listed as an ingredient with a detergent. The effectiveness of the disinfectant may be neutralized.
Chlorine bleach is sometimes called “sodium hypochlorite” or “hypochlorite.” You will encounter it in chlorine bleach, automatic dishwashing detergents, chlorinated disinfectants and cleaners, chlorinated scouring powder, mildew removers, and toilet bowl cleaners.
Do not mix products together. Do not mix them with ammonia or vinegar.
Read the labels of products in your home and following instructions for proper use. Many containers will state the most common dangers from interaction with other products.
Thursday, August 9, 2018
Monday, August 6, 2018
Chemistry Facts
Chemistry is a fascinating science, full of unusual trivia! The following is a list of some of the most fun and most interesting chemistry facts for you.
1.The only elements that are liquid at room temperature are bromine and mercury. However, you can melt gallium by holding a lump in the warmth of your hand.
2.Unlike many substances, water expands as it freezes. An ice cube takes up about 9% more volume than the water used to make it.
3.If you pour a handful of salt into a full glass of water, the water level will actually go down rather than overflowing the glass.
4.Similarly, if you mix half a liter of alcohol and half a liter of water, the total volume of the liquid will be less than one liter.
5.There is about 1/2 lb or 250 g of salt (NaCl) in the average adult human body.
6.A pure element can take many forms. For example, diamond and graphite both are forms of pure carbon.
7.Many radioactive elements actually do glow in the dark.
8.The chemical name for water (H2O) is dihydrogen monoxide.
9.The only letter that doesn't appear on the periodic table is J.
10.Lightning strikes produce O3, which is ozone, and strengthen the ozone layer of the atmosphere.
11.The only two non-silvery metals are gold and copper.
12.Although oxygen gas is colorless, the liquid and solid forms of oxygen are blue.
13.The human body contains enough carbon to provide 'lead' (which is really graphite) for about 9,000 pencils.
14.Hydrogen is the most abundant element in the universe, while oxygen is the most abundant element in the earth's atmosphere, crust, and oceans (about 49.5%).
15.The rarest naturally-occurring element in the earth's crust may be astatine. The entire crust appears to contain about 28 g of the element.
16.Hydrofluoric acid is so corrosive that it will dissolve glass. Although it is corrosive, hydrofluoric acid is considered to be a 'weak acid'.
17.One bucket full of water contains more atoms than there are buckets of water in the Atlantic ocean.
18.Approximately 20% of the oxygen in the atmosphere was produced by the Amazon rainforest.
19.Helium balloons float because helium is lighter than air.
20.Bee stings are acidic while wasp stings are alkaline.
21.Hot peppers get their heat from a molecule called capsaicin. While the molecule acts as an irritant to mammals, including humans, birds lack the receptor responsible for the effect and are immune to the burning sensation from exposure.
22.It's possible to die from drinking too much water.
23.Dry ice is the solid form of carbon dioxide, CO2.
24.Liquid air has a bluish tint, similar to water.
25.You can't freeze helium simply by cooling it to absolute zero. It will freeze if you apply extremely intense pressure.
26.By the time you feel thirsty, you've already lost about 1% of your body's water.
27.Mars is red because its surface contains a lot of iron oxide or rust.
28.Sometimes hot water freezes more quickly than cold water! A high school student documented the effect, which bears his name (the Mpemba effect).
Chemistry question
1.You can't live without iron. Where in the body is most of the iron located?
A.your brain
B.your skin
C.your bone
D.your blood
Answer:-Your blood
Explane:-Most of the body's iron is locked up in the hemoglobin found in red blood cells, used for oxygen transport.
2.The symbol Ag stands for which element?
A.Gallium
B.Silver
C. Gold
D.Magnesium
Answer:-Silver
Explane:-Ag stands for argentum, which is an old name for silver. The term "argent" survives, meaning silvery.
3.. Organic chemistry is the study of the compounds that make up living organisms. All organic molecules contain:
A.Carbon only
B.Carbon and Nitrogen
C.Carbon and Hydrogen
D.Carbon ,Hydrogen and Oxygen
Answer:-Carbon and Hydrogen
Explane:-Not all compounds that contain carbon are organic. An example of an inorganic carbon compound is carbon dioxide. All organics contain both carbon and hydrogen. A quasi-exception would be carbon tetrachloride, which is an organic solvent. It's not actually organic, but it is nonpolar so it dissolves organic molecules.
Sunday, August 5, 2018
What Happens When You Put Dry Ice in Water?
Placing dry ice into water, such as fruit punch, to simulate a boiling cauldron of witch’s brew is a favorite Halloween party trick. Science teachers commonly use this effect to demonstrate the principles of sublimation and condensation.
Dry Ice
“Dry ice” is actually solidified carbon dioxide (CO?). Carbon dioxide is normally a gas at room temperature and pressure. When it is put under high pressure at low temperature, however, it solidifies into what is commonly called “dry ice.” When the dry ice is brought to atmospheric pressure, it remains solid and very cold (-109 °F).
Sublimation
Dry ice is called “dry” because it never enters a liquid state as it melts, unlike ice, which melts into liquid water. Dry ice transforms directly to gaseous carbon dioxide. Scientists refer to this process as “sublimation.”
Water
The water does not play a critical role in this process other than containing a substantial amount of heat that is transferred to the dry ice to sublimate it. Many other liquids could be used in place of water, but water is particularly good at retaining heat (in scientific terms, water has a high specific heat capacity).
Condensation
When a liquid such as water turns into vapor, the process is called evaporation. The reverse process is called condensation. At low temperatures, water will condense out of the air into very small droplets of water.
Clouds
Clouds are actually very small droplets of water (or possibly even ice crystals) that have condensed in the low temperatures of the upper atmosphere. The “witches brew” effect produced by dry ice in water represents the same phenomenon on a smaller scale. As the carbon dioxide sublimes, the gas-phase carbon dioxide is still quite cold. Water in the air condenses in the cold carbon dioxide gas as it rises above the water.
Fun Fact
The long tails of comets are the result of carbon dioxide and other ices sublimating as the comet passes close to the sun.
Friday, August 3, 2018
Logical reasoning-symbol series
A. 1
B. 2
C. 3
D. 4
Answer: Option A
Explanation:
Look carefully at the number of dots in each domino. The first segment goes from five to three to one. The second segment goes from one to three to five. The third segment repeats the first segment.
2.
A. 1
B. 2C. 3
D. 4
Answer: Option C
Explanation:
This is an alternating series. In the first segment, the letter "E" faces right, then down, then right. In the second segment, the letters all face down. To follow this pattern, in the fourth segment, the letters must all face up.
3.
A. 1
B. 2
C. 3
D. 4
Answer: Option B
Explanation:
Notice that in each segment, the figures are all the same shape, but the one in the middle is larger than the two on either side. Also, notice that one of the figures is shaded and that this shading alternates first right and then left. To continue this pattern in the third segment, you will look for a square. Choice b is correct because this choice will put the large square between the two smaller squares, with the shading on the right.
Chemistry quizzes
1. Which acid is present in lemon ?
A.marlic acid
B.citric acid
C.lactic acid
D.tartaric acid
Answer: B
Explanation:citric acid is present in lemon.
A.nitric acid
B.sulphuric acid
C.hydrochloric acid
D.phosphoric acid
Answer:- B
3. Which metal is heaviest ?
A.osmiumB.mercury
C.iron
D.nickle
Answer:-A
Wednesday, August 1, 2018
Chem quiz
1.If you fill a glass to the brim with ice water and the ice melts, what will happen?
A.The glass will over flow as the ice turns to water.
B.The level of water in the glass will remain unchanged as the ice melts.
C.The water level will drop slightly as the ice melts.
Answer: The water level will drop slightly as the ice melt.
2. DNA codes for proteins, which are the building blocks of organisms. What is the most abundant protein in the human body?
A.Tubulin
B.Albumin
C.Collagen
A.The glass will over flow as the ice turns to water.
B.The level of water in the glass will remain unchanged as the ice melts.
C.The water level will drop slightly as the ice melts.
D.I'll never find out because I'll drink the water or walk away before anything happens.
Explane:-One interesting property of water is that it achieves maximum density as a liquid, not as a solid. So, ice is less dense than water and floats. When it melts, it becomes more dense. More mass per unit volume means the level of the liquid drops slightly.
A.Tubulin
B.Albumin
C.Collagen
D.Keratin
Answer;Collagen
Explane:-You'll find keratin primarily in your hair, nails, and skin, but the most abundant protein in humans is collagen, which is found in bone and cartilage. Both proteins are strong and flexible.
3.What is the most common isotope of hydrogen?
A.Protium
B.Deuterium
C.Tritum
D.Hydrogen only has one isotope
Answer;-Protium
Explane:-Most of the hydrogen in the world is protium (one proton, no neutrons), but some deuterium and tritium occurs, too. Tritium is radioactive. Deuterium is not radioactive and is the form of hydrogen found in heavy water.
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