1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Musya8 [376]
3 years ago
7

When a sample of a compound in the vitamin D family was burned in a combustion analysis, 5.983 mg of the compound gave 18.490 mg

of CO2 and 6.232 mg of H2O. This compound was found to have a molecular mass of 399. What is the molecular formula of this compound? Put your answer in form of CxHyOz.
Chemistry
2 answers:
enyata [817]3 years ago
6 0

Answer:

Molecular formula C33H27O3

Explanation:

<u>Given:</u>

Mass of CO2 produced = 18.490 mg

Mass of H2O produced = 6.232 mg

Mass of sample = 5.983 mg

<u>To determine:</u>

Molecular formula of the compound

<u>Calculation:</u>

<u>Step 1</u>: Calculate the mass of carbon in the sample

Molar Mass of CO2 = 44 g/mol

Moles of CO2 = \frac{Mass}{Molar mass } = \frac{18.490}{44} =0.4202

The carbon content in the sample corresponds to the amount of CO2 produced

Moles of C in the sample = 0.4202

Mass of C = moles * atomic mass of C

                = 0.4202 moles * 12 g/mol = 5.0424 g

<u>Step 2 </u>: Calculate the mass of hydrogen in the sample

Molar Mass of H2O = 18 g/mol

Moles of H2O = \frac{Mass}{Molar mass } = \frac{6.232}{18} =0.3462

The hydrogen content in the sample corresponds to the amount of H2O produced

Moles of H in the sample = 0.3462

Mass of H = moles * atomic mass of H

                = 0.3462 moles * 1 g/mol = 0.3462 g

<u>Step 3</u>: Mass of O in the sample

Mass of O = Total mass - Mass of C - Mass of H

= 5.983 - 5.0424-0.3462=0.5944 g

<u>Step 4</u>: Moles of O

Moles of O = mass of O/atomic mass = 0.5944/16 = 0.03715

Step 5: Find the empirical formula

Moles of C = 0.4202

Moles of H = 0.3462

Moles of O = 0.03715

Ratio

C = \frac{0.4202}{0.03715} =11.31\\

H = \frac{0.3462}{0.03715} =9.32\\

O = \frac{0.03715}{0.03715} =1.00\\

Empirical formula = C11H9O

<u>Step 6</u>: Find n

Empirical formula mass = 12(11) + 1(9) + 16 = 157

n = n = \frac{Molar\ Mass}{Empirical\ Mass} = \frac{399}{157} =2.54

n = 3.0

<u>Step 7</u>: Find molecular formula

(C11H9O)3 = C33H27O3

Jet001 [13]3 years ago
5 0
We calculate it as follows:

Moles CO2 = 0.01849 g / 44 = 0.000420 
<span>Mass C = 0.000420 x 12 = 0.00504 g </span>
<span>Moles H = 2 x 0.006232 / 18 = 0.000692 </span>
<span>Mass H = 0.000692 g </span>
<span>Mass O = 0.005982 - ( 0.00504 + 0.000692) = 0.00025 </span>
<span>Moles O = 0.00025 / 16 = 0.0000156 </span>
<span>C 0.000420
H 0.000692
O 0.0000156 
</span>
<span>divide each by the smallest value, giving you the chemical formula as:
</span><span>
C27H44O</span>
You might be interested in
Write the Henderson-Hasselbalch equation for a solution of formic acid. Calculate the quotient [HCO2]/[HCO2H] at (a) pH 3.000; (
Elena L [17]

Answer:

a. 0.182

b. 1.009

c. 1.819

Explanation:

Henderson-Hasselbach equation is:

pH = pKa + log [salt / acid]

Let's replace the formula by the given values.

a. 3 = 3.74 + log [salt / acid]

3 - 3.74 = log [salt / acid]

-0.74 = log [salt / acid]

10⁻⁰'⁷⁴ = 0.182

b. 3.744 = 3.74 + log [salt / acid]

3.744 - 3.74 = log [salt / acid]

0.004 = log [salt / acid]

10⁰'⁰⁰⁴ = 1.009

c. 4 = 3.74 + log [salt / acid]

4 - 3.74 = log [salt / acid]

0.26 = log [salt / acid]

10⁰'²⁶ = 1.819

3 0
3 years ago
The bonds of the product store 27 KJ more energy than the bonds of the reactants how is energy conserved during this reaction
Blababa [14]

If the bonds of the product store 27 KJ more energy than the bonds of the reactants, It means the surroundings absorb 27 kj of energy from the reaction system Hence, Option (D) is the correct answer

<h3>What is the Exothermic reaction ?</h3>

An exothermic process releases heat, causing the temperature of the immediate surroundings to rise.

The bonds of the product store 27 KJ more energy than the bonds of the reactants, It means that energy has been absorbed by the surrounding as the product formed is more stable due to more stronger bond

This can be inferred from more stored energy with in the bonds and Thus, It is a exothermic reaction.Hence, Option (D) is the correct answer

Learn more about exothermic reaction here ;

brainly.com/question/9799465

#SPJ1

6 0
2 years ago
Sometimes a cloud may form at or near the ground when the ground cools at night. This cloud is known as...
melomori [17]

Answer:

im belive the answers fog

8 0
2 years ago
Read 2 more answers
Which element has the same number of valence electrons as hydrogen (H)? A. helium (He). . B. oxygen (O). . C. nitrogen (N). . D.
deff fn [24]
Li is in group 1 so it has same number of valence electrons as hydrogen.
hope it helps.
4 0
3 years ago
Read 2 more answers
About 3% of the water on Earth is freshwater. Only about 40% of that freshwater is available for human use. Why is so much fresh
Ilya [14]
I believe the answer you're looking for is B. It's Polluted. I hope this helps.
3 0
3 years ago
Read 2 more answers
Other questions:
  • Calculate the mass, in grams, of a single xenon atom (mxe = 131.29 amu ).
    8·1 answer
  • You are trying to determine the volume of the balloon needed to match the density of the air in the lab. You know that if you ca
    14·1 answer
  • How can toxicant absorption be reduced after exposure to the skin? How can absorption be reduced for orally consumed chemicals?
    12·1 answer
  • If particles have enough kinetic energy to partly overcome
    14·1 answer
  • Bread dough rising<br> gas formation<br> color change<br> light emission
    13·2 answers
  • When the following molecular equation is balanced using the smallest possible integer coefficients, the values of these coeffici
    14·1 answer
  • Helllllp meh pleaseeeeeee
    15·2 answers
  • Find the mass of a 60 ML volume of water if the density of water is 1 g/mL
    11·1 answer
  • What results when two or more atoms share electrons equally?
    8·1 answer
  • At what point on the roller coaster do the riders have the greatest amount of potential energy?
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!