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A Learning Portal from Recruitment India
What are the number of moles of CO2 which contains 16 g of oxygen?
0.2 MOLE
0.5 MOLE
0.4 MOLE
0.25 MOLE
Answer with explanation
Answer: Option BExplanation
One mole of CO2 has mass of 44 g and 32 g of O2. So 16 g of O2 have 22 g of CO2 or 0.5 moles of it.
(or)
Mass of carbon (1 atom) = 12g.
Mass of oxygen (2 atoms) = 16*2 = 32g.
Given mass = 16g.
No.of moles = given mass/actual mass.
=16g/32g.
=0.5g.
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The paramagnetic character of the metals is due to ______.
Number of holes more than electrons
Completely filled orbits
Low melting point
Unpaired electrons
Answer with explanation
Answer: Option DExplanation
Unpaired electrons-The paramagnetic character exhibited by those compounds which have unpaired electrons.paramagnetic character is directly proportional to number of unpaired electrons. … this is due to 5 unpaired electrons as manganese is present in +2 state. it has configuration 3d5
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Nuclear particles responsible for holding all nucleons together are
electrons
protons
neutrons
mesons
Answer with explanation
Answer: Option DExplanation
Mesons are hadronic subatomic particles composed of one quark and one antiquark, bound together by the strong interaction.
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Elements with the same atomic number but different mass numbers are called _________.
Isobars
Isotopes
Isotones
Isomers
Answer with explanation
Answer: Option BExplanation
Isotopes are atoms with the same number of protons but that have a different number of neutrons. Since the atomic number is equal to the number of protons and the atomic mass is the sum of protons and neutrons, we can also say that isotopes are elements with the same atomic number but different mass numbers.
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Potassium Permanganate is used for purifying drinking water, because_________
It is a reducing agent
It is an oxidising agent
It is a sterilising agent
It dissolves the impurities of water
Answer with explanation
Answer: Option BExplanation
Potassium permanganate(KMnO4) is a strong oxidizing agent that does not generate toxic byproducts. It is used extensively in the water treatment industry. It was used to disinfect drinking water and can turn the water pink. Now a days it is used in control of nuisance organisms such as zebra mussels in fresh water collection and treatment systems.
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Which element is present in the largest amount in rocks and minerals?
Hydrogen
Carbon
Oxygen
Silicon
Answer with explanation
Answer: Option DExplanation
Silicon- Silicon is the most easily available semiconductor metal which is present in largeamount in rocks and minerals. Silicon is also the basic component of sand ,and sand is the basic component of almost every rocks and impure minerals.
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Photochemical smog is a resultant of the reaction among
NO₂, O₃ and peroxy acetyl nitrate in the presence of Sunlight
High concentration of NO₂, O₃ and CO in the evening
NO₂, and peroxy acetyl nitrate in the presence of Sunlight
CO, CO₂ and NO₂ at low temperature
Answer with explanation
Answer: Option AExplanation
NO₂, O₃ and peroxy acetyl nitrate in the presence of Sunlight
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When H₂ gas is allowed to expand from a region of high pressure to a region of low pressure the temperature of the gas
decreases to a small extent
increases
does not change
decreases suddenly
Answer with explanation
Answer: Option BExplanation
increases
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