TARGET SSC: Chemistry Test- 4
1. The pollutant responsible for ozone holes is _____?
2. One of the best solutions to get rid of non-biodegradable wastes is
3. The alkaloid naturally found in coffee, cocoa and cola nut is
4. The metal used for aircrafts and rockets is
5. Which of the following is not a noble gas?
6. The isotope used for the production of atomic energy is
7. Which of the following is not a nucleon?
8. The pair of compounds used as anaesthetic in medicines
- Ether, Ammonia
- Nitrous oxide, Chloroform
- Chloroform, Nitrogen dioxide
- Nitrogen dioxide, ether
9. The compound that has the least value for octane number
- 2- methyl heptane
- 2, 2- dimethyl hexane
10. The percentage of carbon in cast iron is
- 0.01 to 0.25
- 0.5 to 1.5
- 6 to 8
- 3 to 5
The ozone layer forms a thick layer in stratosphere, encircling the earth, that has large amount of ozone in it. It protects our planet i.e. Earth from the harmful radiations that comes from the sun. The ozone layer was discovered in 1913 by the French physicists Charles Fabry and Henri Buisson.
Ozone depleting substances (ODSs) are those substances which deplete the ozone layer and are widely used in refrigerators, airconditioners, fire extinguishers, in dry cleaning, as solvents for cleaning, electronic equipment and as agricultural fumigants.
Ozone depleting substances controlled by Montreal Protocol include:
- Chlorofluorocarbons (CFCs): The most widely used ODS, accounting for over 80% of total stratospheric ozone depletion.
- Carbon tetrachloride (CCl4), Methyl chloroform (CH3CCl3)
- Hydrobromofluorocarbons (HBFCs)
- Hydrochlorofluorocarbons (HCFCs)
- Methyl bromide (CH3Br)
- Bromochloromethane (CH2BrCl)
Noble gas, any of the seven chemical elements that make up Group 18 (VIIIa) of the periodic table. The elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and element 118 (temporarily named ununoctium [Uuo]).
Natural uranium as found in the Earth’s crust is a mixture largely of two isotopes: uranium-238 (U-238), accounting for 99.3% and uranium-235 (U-235) about 0.7%.
The isotope U-235 is important because under certain conditions it can readily be split, yielding a lot of energy. It is therefore said to be ‘fissile’ and we use the expression ‘nuclear fission’.
Meanwhile, like all radioactive isotopes, they decay. U-238 decays very slowly, its half-life being about the same as the age of the Earth (4500 million years). This means that it is barely radioactive, less so than many other isotopes in rocks and sand. Nevertheless it generates 0.1 watts/tonne as decay heat and this is enough to warm the Earth’s core. U-235 decays slightly faster.
A nucleon is one of the particles that makes up the atomic nucleus. Each atomic nucleus consists of one or more nucleons, and each atom in turn consists of a cluster of nucleons surrounded by one or more electrons. There are two known kinds of nucleon: the neutron and the proton.
In the measurement of octane quality of gasoline a mixture of two hydrocarbons called iso-octane and normal heptane. Iso-octane is assigned an octane rating of 100, and normal heptane is assigned an octane rating of zero. A blend of 90% iso-octane and 10% n-heptane would have an octane rating of 90 octane.