Calculation of percent composition
analysis of a 12.04-g sample of a liquid compound composed of carbon, hydrogen, and nitrogen showed it to contain 7.34 g c, 1.85 g h, and 2.85 g n. what is the percent composition of this compound?

C: 61.0%, H: 15.3%, N: 23.7%

Explanation:

We can calculate the percent by mass of each element using the following expression.

%Element = (mass of the element/mass of the compound) × 100%

Carbon

%C = (7.34 g/12.04 g) × 100% = 61.0%

Hydrogen

%H = (1.85 g/12.04 g) × 100% = 15.3%

Nitrogen

%N = (2.85 g/12.04 g) × 100% = 23.7%

The percent composition of this compound is C: 61.0%, H: 15.3%, N: 23.7%.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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