Questions about adenine (help asap pls)

Question

The first four questions will apply to adenine (C5H5N5), a purine base found in DNA, RNA, and ATP

1.   Units of weight: grams vs. Daltons

 "How much does  one molecule/one mole of this molecule weigh?"

2.   Covalent bonding: atoms, covalent bonds, and molecules

 "How many atoms/bonds are found in this molecule?"

3.   Covalent bonds: polar vs. nonpolar

"How many polar covalent bonds/nonpolar covalent bonds does this molecule contain? (Note: Count double bonds as TWO covalent bonds.)"

4.   Covalent bonding: orbitals and hybridization

 "How many atoms in this molecule have undergone sp³ hybridization?"

For #1 I got 135.13 D and 135.13 g/mole

For #2 I got 20 atoms and 20 covalent bonds

For #3 I got 15 polar covalent bonds and 5 non-polar bonds

For #4 I got 2 sp^3 hybridization

Could you please let me know if my answers are correct and if not explain the correct answer?

Answer 1

#1 is correct. 1 Dalton = 1g/mole.

For #2 there are 15 atoms: 5 carbon atoms, 5 hydrogen atoms, and 5 nitrogen atoms. There are 16 covalent bonds: 12 single and 4 double covalent bonds. If each double bond counts as two covalent bonds then there are a total of 20 covalent bonds.

#3 is also correct. CH bonds are non-polar, as well as CC bonds. CN bonds and NH bonds are all polar.

#4 is also correct. The only two atoms that are SP3 hybridized are the two N atoms at the upper left of the molecule.