Could someone please tell me what is the general chemical formula for starch?

Answer 1

Starch is a polysaccharide consisting of many glucose molecules (C6H12O6). For each bond forming between two glucose molecules you have one water molecule being lost.

In the simplest case you would have a linear polymer of n glucose molecules. Then you would be losing n-1 H2O so you would have C=6n, H=12n-2(n-1)=10n+2, O=6n-(n-1)=5n+1
So the formula would be C(6n)H(10n+2)O(5n+1).

In reality you also have branches of glucose chains so the actual number of H2O that is lost is bigger.

Answer 2

Urea is an organic compound with the chemical formula (NH2)2CO. Urea is also known as carbamide, especially in the recommended International Nonproprietary Names (rINN) in use in Europe. For example, the medicinal compound hydroxyurea (old British Approved Name) is now hydroxycarbamide. Other names include carbamide resin, isourea, carbonyl diamide, and carbonyldiamine. It was the first organic compound to be artificially synthesized from inorganic starting materials, thus dispelling the concept of vitalism. Urea is highly soluble in water and is therefore an efficient way for the human body to expel excess nitrogen. Due to extensive hydrogen bonding with water (up to six hydrogen bonds may form[citation needed], two from the oxygen atom and one from each hydrogen), it is very soluble and thus is also a good fertilizer. The urea molecule is planar and retains its full molecular point symmetry, due to conjugation of one of each nitrogen's P orbital to the carbonyl double bond. Each carbonyl oxygen atom accepts four N-H-O hydrogen bonds[citation needed], a very unusual feature for such a bond type. This dense (and energetically quite favourable) hydrogen bond network is probably established at the cost of efficient molecular packing: the structure is quite open, the ribbons forming tunnels with square cross-section.

Answer 3

Starch is a very general term for many types of complex sugar molecules. Sorry, but there is no one answer to your problem.

Answer 4

That depends on the length of the startch, but the general ratio is that of a carbohydrate:

CnH2nOn where n is a multiple of 6.