Hydrocarbons are compounds that contain
(1) carbon, only
(2) carbon and hydrogen, only
(3) carbon, hydrogen, and oxygen, only
(4) carbon, hydrogen, oxygen, and nitrogen, only

Once similarity and one difference between a mixture of elements and a mixture of compounds

Scientists often have to deal with numbers that are either very large or very small. for example, the radius of the sun is approximately 696,000 kilometers, while bacterial cells are as small as 1.9 × 10-4 millimeters. express each number in an alternate form.

Akno3 solution containing 51 g of kno3 per 100.0 g of water is cooled from 40 ∘c to 0 ∘c. what will happen during cooling?