Chemistry, 08.08.2019 06:20 alwaysneedhelp84

when 3.539 grams of a hydrocarbon, cxhy, were burned in a combustion analysis apparatus, 12.15 grams of co2 and 1.990 grams of h2o were produced.
in a separate experiment, the molar mass of the compound was found to be 128.2 g/mol. determine the empirical formula and the molecular formula of the hydrocarbon.
enter the elements in the order presented in the question.
empirical formula =
molecular formula =

Answers: 1

Show answers

Answers

Answer from: helpmelol37

The empirical formula and molecular formula for the given hydrocarbon is, and $C_{10}H_{10}$ respectively.

Explanation :

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_y+O_2\rightarrow CO_2+H_2O$

where, 'x' and 'y' are the subscripts of Carbon and hydrogen respectively.

We are given:

Mass of CO_2=12.15g

Mass of H_2O=1.990g

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 12.15 g of carbon dioxide, $\frac{12}{44}\times 12.15=3.314g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18 g of water, 2 g of hydrogen is contained.

So, in 1.990 g of water, $\frac{2}{18}\times 1.990=0.221g$ of hydrogen will be contained.

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{3.314g}{12g/mole}=0.276moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.221g}{1g/mole}=0.221moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.221 moles.

For Carbon = $\frac{0.276}{0.221}=1.25\approx 1$

For Hydrogen = $\frac{0.221}{0.221}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H = 1 : 1

Hence, the empirical formula for the given compound is C_1H_1=CH

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{molecular mass}}{\text{empirical mass}}$

We are given:

Mass of molecular formula = 128.2 g/mol

Mass of empirical formula = CH=12+1=13g/mol

Putting values in above equation, we get:

$n=\frac{128.2g/mol}{13g/mol}=9.86\approx 10$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{n}H_{n}=C_{10}H_{10}$

Thus, the molecular formula for the given organic compound is $C_{10}H_{10}$

Answer from: Quest

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.

Answer from: Quest

the answer is c.the valence of the atoms combine .

Another question on Chemistry

Chemistry, 21.06.2019 15:40

Which of the following might a chemist choose to study? a. glacier movement in alaska b. better ways to recycle plastics c. the effects of hurricanes on turtle populations d. the vibrations in bridges caused by big trucks

Answers: 2

Answer

Chemistry, 22.06.2019 03:30

Select the correct answer. when carbon dioxide dissolves in water, it sometimes reacts with water to form carbonic acid as in this balanced equation: co2 + h2o → h2co3. if 495 milliliters of carbon dioxide at 25°c and 101.3 kilopascals reacts with excess water, what is the theoretical yield of carbonic acid? use the periodic table and the ideal gas resource a. 0.889 g b. 1.10g c. 1.27g d. 2.02g what's the answer! quick!

Answers: 1

Answer

Chemistry, 22.06.2019 04:20

Explanation for basic character?

Answers: 2

Answer

Chemistry, 22.06.2019 07:30

The scheme below is from a series of reactions that are part of a synthesis of vitamin a. answer the following questions with reference to this scheme. (i) what is "reagent a"? (ii) draw a step-by-step mechanism which explains the formation of compound c from compound b (iii) which reagents would you use to form compound e from compounds c and d (reagents b and c)? for each reagent suggested above in (ii) explain the role of the reagent in the reaction to (iv) form compound e. you may wish to do this by drawing a mechanism. 1. addition of reagent a но reagent a 2. н,о" thо oh нон-с compound a. compound b. compound c .ch-оh 1. reagent b "сно 2. reagent c сh oh compound e. compound d.

Answers: 2

Answer

You know the right answer?

when 3.539 grams of a hydrocarbon, cxhy, were burned in a combustion analysis apparatus, 12.15 grams...

Questions