Part a) theobromine, c7h8n4o2, is a component of chocolate. it is mildly diuretic, is a mild stimulant, and relaxes the smooth muscles of the bronchi in the lungs. because dogs metabolize it more slowly than humans, theobromine is very toxic to dogs.
if there are 0.064 g of theobromine in a 43 g chocolate bar, how many moles of theobromine are there?
a) 1.5 x 10−3 moles
b) 3.55181 x 10−4 moles
c) 3.6 x 10−4 moles
d) 12 moles
part b) calculate the molarity (m) of 151.1 g of h2so4 in 1.405 l of solution.
express your answer to four significant figures.
part c) sodium hydroxide, naoh, is a strong base that is used in industrial synthesis and processes such as making paper.
what is the mass of 2.30 ×1022 molecules of naoh (molar mass = 40.0 g/mol)?
express the mass in grams to three significant figures.

a. 3,6x10⁻⁴ moles

b. 1,096M

c. 1,53 g of NaOH

Explanation:

a. Theobromine has a molar mass of:

C: 12,01×7= 84,07 g/mol

H: 1,01×8= 8,08 g/mol

N: 14×4= 56,04 g/mol

O: 16×2= 32 g/mol

84,07 g/mol + 8,08 g/mol + 56 g/mol + 32 g/mol = 180,15g/mol. Thus, in 0,064g of theobromine are:

= 3,6x10⁻⁴ moles -two significant figures-

b. Molar mass of H₂SO₄ is 98,079 g/mol.

151,1g are:

= 1,54 moles of H₂SO₄

As molarity is moles of solute per liters of solution, molarity is:

1,54 moles of H₂SO₄ / 1,405L = 1,096 M

c. 2,30x10²² molecules of NaOH are:

2,30x10²²molecules × (1mol/6,022x10²³molecules) = 0,0382 moles of NaOH

As molar mass of NaOH is 40,04g/mol:

= 1,53 g of NaOH

I hope it helps!

the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.