Chemistry Questions

A 40% solution of Formaldehyde known as Formalin is used in the preservation of biological specimens because of its hardening action on proteins. 

Vitamins are essential nutrients found in foods. They perform specific and vital functions in a variety of body systems, and are crucial for maintaining optimal health.

The two different types of vitamins are fat-soluble vitamins and water-soluble vitamins.

Fat-soluble vitamins :

 Vitamins A, D, E and K — dissolve in fat before they are absorbed in the bloodstream to carry out their functions. Excesses of these vitamins are stored in the liver, and are not needed every day in the diet.

Water-soluble vitamins :

Vitamins dissolve in water and are not stored by the body. Since they are eliminated in urine, we require a continuous daily supply in our diet. The water-soluble vitamins include the vitamin B-complex group and vitamin C.

Water-soluble vitamins are easily destroyed or washed out during food storage or preparation.

Here in the given options, Gold is a malleable substance.

Malleable substance means a metal or a material able to be hammered or pressed into shape without breaking or cracking. i.e, tensile.

A sample of matter must be copper if each atom in the sample has 29 protons.

A closed room is aplace where charcoal is burnt in limited supply of air. There is every chance for the formation of the deadly poisonous carbon monoxide, which when inhaled, reacts with the iron in haemoglobin of blood and prevents the supply of oxygen. It is said to be treacherous as there can be no previous warning of its presence because it is an odourless and colourless gas.

The halogens make up group 17 in the periodic table.

They are five elements:

Chlorine (Cl)

Fluorine (F)

Bromine (B)

Iodine (I)

Astatine (At).

But astatine is not purely halogen as it is radioactive.

A substance that cannot be decomposed (broken down) into simpler substances by ordinary chemical means.

Examples: gold, iron, carbon, hydrogen, oxygen, nitrogen.

Material composed of only one kind of matter throughout (same atoms or same molecules).

The boiling point of the compounds depend on the number of carbons in them. Hexane has 6, Pentane has 5 and Propane has 3 carbons. As Hexane is with 6 carbons it has highest boiling point and next Pentane with 5 and lowest Propane with 3.