c. Isotopes differ only in their number of neutrons – so they contain 0, 1, and 2 neutrons, respectively.

The ans is C

Isotopes have the same number of protons but different number of neutrons.

Answer:

The given statement is TRUE

Explanation:

Sulfur oxides (SOx) are compounds of sulfur and oxygen molecules. Sulfur dioxide (SO2) is the pre- dominant form found in the lower atmosphere. It is a colorless gas that can be detected by taste and smell. Scrubbers help to remove most of the sulfur oxides from the smoke stack exhaust of a power plant. In the scrubber, there is a water spray that produces a cloud of fine water droplets. The water is mixed with crushed limestone, which reacts with the sulfur and pulls it out of the exhaust

Answer: b. pollution causes destruction of coral reefs, which are important sources of shelter and breeding for marine animals

Explanation:

Some of the air pollutants like carbon dioxide, carbon monoxide and sulfuric acid mixes with the marine water also the solid waste materials which are discharge in water and oil spill also contaminate the quality of marine water.  The pollutants directly influence the life of the marine animals. They cause destruction of the coral reefs. Water pollutants such as fertilizers, oils, animal wastes can block the sunlight reaching the reef. This can cause coral bleaching which may occur due to the removal of the algal colony living in symbiotic association with the coral polyp. The poisonous pollutants can kill the coral polyps and this will leave many marine creatures devoid of shelter. Hence, some marine species will not be able to  copulate and reproduce. Thus they may become extinct.

Hydrogen bonds are not like covalent bonds. They are nowhere near as strong and you can’t think of them in terms of a definite number like a valence. Polar molecules interact with each other and hydrogen bonds are an example of this where the interaction is especially strong. In your example you could represent it like this: 

H2C=O———H-OH 

But you should remember that the H2O molecule will be exchanging constantly with others in the solvation shell of the formaldehyde molecule and these in turn will be exchanging with other H2O molecules in the bulk solution. 

Formaldehyde in aqueous solution is in equilibrium with its hydrate. 

H2C=O + H2O <—————–> H2C(OH)2

 The chemical formula of Helium is He. 

Question 1 : 

Given n = 1.11 x 10^-6 

To get no. of the particle, 
No of particle = no. of mole x Avogadro Constant 
p = n x NA 

1 mol of Helium = 6.02 x 10^23 

No of atoms = (6.02 x 10^23) x (1.11 x 10^-6) 
= 6.66 x 10^17 

………………………….. 

Question 2 : 

Given p = 4.29×10^21 

p = n x NA 
4.29 x 10^21 = n x (6.02 x 10^23) 
(4.29 x 10^21) / (6.02 x 10^23) = n 
n = Approximately 7.126 x 10^-3 

Hope the answer is right 🙂