Question

aldehydes and ketones are very similar in that they both contain
phosphorus atoms
sulfur atoms
a carbonyl group
nitrogen atoms
the same r group

molecules containing many hydroxyl groups tend to be *
basic
structurally less stable than those with fewer hydroxyls
complex macromolecules
soluble in water
nonpolar

the monomer of a carbohydrate is a(n) *
amino acid
simple sugar (monosaccharide)
fatty acid
glycerol
nucleotide

the two covalent bonds in a water molecule are polar because?
oxygen and hydrogen have similar electronegativities.
oxygen is more electronegative than hydrogen.
hydrogen is more electronegative than oxygen.
water a small molecule.
water is hydrophilic.

Explanation:

1. Aldehydes have a carbon - oxygen double bond (carbonyl) with the carbon of the carbonyl bonded to a hydrogen and another group, while ketones have a carbon - oxygen double bond with the carbonyl carbon bonded to two other carbon - containing groups. So they both contain a carbonyl group.
2. Hydroxyl groups ($-OH$) are polar and can form hydrogen bonds with water molecules. Molecules with many hydroxyl groups are soluble in water due to these hydrogen - bonding interactions.
3. Carbohydrates are polymers made up of monomers called monosaccharides (simple sugars).
4. In a water molecule ($H_2O$), oxygen is more electronegative than hydrogen. This causes the shared electrons in the covalent bonds between oxygen and hydrogen to be pulled closer to the oxygen atom, creating a polar bond.

Answer:

1. C. a carbonyl group
2. D. soluble in water
3. B. simple sugar (monosaccharide)
4. B. oxygen is more electronegative than hydrogen.