serotonin, composed of c, h, n, and o, facilitates neuronal communication. the molar mass of serotonin is 176.00 g/mol. by combustion of a 5.31 g sample, serotonin was found to contain 13.3 g carbon dioxide, 3.24 g water. separate analysis shows it to be 15.9% nitrogen. determine the empirical and molecular formulas of serotonin

C₂H₁₂N₂O

Explanation:

The elements that make up the compound, serotonin are; carbon, C, hydrogen, H, nitrogen, N, and oxygen, O

The molar mass of serotonin, M = 176.00 g/mol

The mass of carbon dioxide obtained from the combustion of 5.31 g sample of serotonin = 13.3 g

The mass of water produced = 3.24 g

The percentage by mass of nitrogen per mole of serotonin = 15.9 %

The molar mass of CO₂, M = 44.01 g/mol

The mass of carbon in 13.3 g of CO₂ = 12/44.01 × 13.3 ≈ 3.36 grams

The number of moles of carbon = 3.63/12 = 0.3

The mass of nitrogen = 0.159 × 5.31 g = 0.84429 g

The number of moles of nitrogen = 0.84429/14 ≈ 0.06 moles

The mass of hydrogen, H₂ = 2/18.01528 × 3.24 g ≈ 0.36 g

The number of moles of hydrogen ≈ 0.36 moles

The mass of oxygen = 5.31 - 0.84429 - 0.36 - 3.626 = 0.47971

The number of moles of oxygen = 0.47971/16 ≈ 0.03

Dividing by 0.03 gives;

H (0.36/0.03 = 12), N(0.06/0.03 = 2), C(0.3/0.03 = 10) O(0.03/0.03 = 1)

The empirical formula is C₂H₁₂N₂O

out of these options:

ability to burn paper

pure sodium reacting violently with water

the boiling point of water

helium does not tend to react with anything

i would say this is a physical property:

helium does not tend to react with anything

why? :

i said helium does not tend to react with anything because well, it reacts to ! but ability to burn paper, pure sodium reacting violently with water, & the boiling point of water are chemical or

physical properties: the properties of a substance that can be observed without changing the chemical makeup of the substance

chemical properties: properties of a substance relating to the chemical nature and reactivity of the substance

the atomic mass is the bottom number on the element.

-steel jelly