How do you think the physical properties of carbon, hydrogen, and oxygen change when they combine to form sugar?

Carbon, hydrogen and oxygen are the elements that make up sugars including sucrose, white table sugar.

Carbon is a solid at room temperature and is found in three different forms: Coal, graphite and diamond. Graphite and coal are soft while diamond, which has covalent network bonding, is a very hard material.  All are insoluble in water. Graphite and coal are dark gray to black. Carbon has a melting point of about 3500 degrees C.

Oxygen and hydrogen are both colorless gases at room temperature, with boiling points of -183 and -253 degrees C respectively.

The sugars that contain these three elements have very different properties. Sucrose and glucose are water-soluble colorless crystalline solids that appear white in the granulated form. Sucrose has a melting point of 186 degrees C and glucose melts at 146 degrees C. Glucose is  more often available as  a thick, syrup-like aqueous solution. The molar masses of sugars are much higher than those of their constituent elements:

sucrose - 342 g/mol

glucose - 180 g/mol

hydrogen gas - 2 g/mol

oxgen gas - 32 g/mol

carbon - 12 g/mol

There are other sugars with the same chemical formulas as sucrose and glucose, but different structural formulas. They have physical properties similar to those of sucrose and glucose.

Note that although sugars contain the elements carbon, hydrogen and oxygen, they aren't produced directly from their elements. Sugars are plant products that are produced from the carbon dioxide gas and water that plants take in.