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
Maru [420]
3 years ago
15

Anabolic steroids are sometimes used illegally by athletes to increase muscle strength. A forensic chemist analyzes some tablets

suspected of being a popular steroid.
He determines the substance contains only C,H and O and has a molar mass of 300.42g/mol.

When a 1.200g sample is subjected to combustion analysis, 3.516g of CO2 and 1.007g H2O are collected.a) What is the empirical formula of the unknown substance in the tablets?b)What is the molecular formula of the unknown substance in the tablets?
Chemistry
1 answer:
11111nata11111 [884]3 years ago
6 0

Answer:

The empirical formula is = C_{10}H_{14}O

The formula of steroid = C_{20}H_{28}O_2

Explanation:

Mass of water obtained = 1.007 g

Molar mass of water = 18 g/mol

Moles of H_2O = 1.007 g /18 g/mol = 0.0559 moles

2 moles of hydrogen atoms are present in 1 mole of water. So,

Moles of H = 2 x 0.0559 = 0.1119 moles

Molar mass of H atom = 1.008 g/mol

Mass of H in molecule = 0.1119 x 1.008 = 0.1128 g

Mass of carbon dioxide obtained = 3.516 g

Molar mass of carbon dioxide = 44.01 g/mol

Moles of CO_2 = 3.516 g  /44.01 g/mol = 0.0799 moles

1 mole of carbon atoms are present in 1 mole of carbon dioxide. So,

Moles of C = 0.0799 moles

Molar mass of C atom = 12.0107 g/mol

Mass of C in molecule = 0.0799 x 12.0107 = 0.9595 g

Given that the steroids only contains hydrogen, oxygen and carbon. So,

Mass of O in the sample = Total mass - Mass of C  - Mass of H

Mass of the sample = 1.200 g

Mass of O in sample = 1.200 - 0.9595 - 0.1128 = 0.1277 g  

Molar mass of O = 15.999 g/mol

Moles of O  = 0.1277 / 15.999  = 0.00798 moles

Taking the simplest ratio for H, O and C as:

0.1119 : 0.00798 : 0.0799

= 14 : 1 : 10

The empirical formula is = C_{10}H_{14}O

Molecular formulas is the actual number of atoms of each element in the compound while empirical formulas is the simplest or reduced ratio of the elements in the compound.

Thus,  

Molecular mass = n × Empirical mass

Where, n is any positive number from 1, 2, 3...

Mass from the Empirical formula = 10×12 + 14×1 + 16= 150 g/mol

Molar mass = 300.42 g/mol

So,  

Molecular mass = n × Empirical mass

300.42 = n × 150

⇒ n = 2

The formula of steroid = C_{20}H_{28}O_2

You might be interested in
A scientist measures the standard enthalpy change for the following reaction to be -327.2 kJ : P4O10(s) 6 H2O(l)4H3PO4(aq) Based
OleMash [197]

Answer:

ΔH°f P4O10(s) = - 3115.795 KJ/mol

Explanation:

  • P4O10(s) + 6H2O(l) ↔ 4H3PO4(aq)
  • ΔH°rxn = ∑νiΔH°fi

∴ ΔH°rxn = - 327.2 KJ

∴ ΔH°f H2O(l) = - 285.84 KJ/mol

∴ ΔH°F H3PO4(aq) = - 1289.5088 KJ/mol

⇒ ΔH°rxn = (4)(- 1289.5088) - (6)(- 285.84) - ΔH°f P4O10(s) = - 327.2 KJ

⇒ ΔH°f P4O10(s) = - 5158.035 + 1715.04 + 327.2

⇒ ΔH°f P4O10(s) = - 3115.795 KJ/mol

5 0
3 years ago
Which type of energy in gasoline is transformed into mechanical energy and a motorcycle engine
vichka [17]
"Chemical Energy" <span>in gasoline is transformed into mechanical energy and a motorcycle engine

Hope  this helps!</span>
7 0
3 years ago
(06.01 MC)
skelet666 [1.2K]

Answer:

Part 1. When the balloon is filled half of the way, and placed into the freezer, it will shrink. This happens because kinetic molecular theory tells us that a decrease in temperature decreases the kinetic energy of the gas molecules in the balloon. Viscous gases like hydrogen are less likely to shrink.

Part 2. When the balloon is placed out in the hot sun, most likely the balloon will swell and grow. This happens because the kinetic energy of the gas molecules increases due to solar radiation transforming into heat energy and then transforming into kinetic energy. Sticky gases like neon are more likely to grow.

Explanation:

7 0
3 years ago
Why do you think the atomic number is basically represented by the number of protons and not the number of electrons?
Naya [18.7K]

Answer:

The atomic number equals the charge on the nucleus. It therefore also equals the number of protons in the nucleus and also equals numerically the number of electrons in the neutral atom. i think so, hope this helps you

Explanation:

6 0
3 years ago
Write the complete balanced equation for the reaction between aluminum metal (Al) and oxygen gas (O2). You do not need to make t
Soloha48 [4]
For the answer to the question above, asking to w<span>rite the complete balanced equation for the reaction between aluminum metal (Al) and oxygen gas (O2)and You do not need to make the subscripts smaller.
My answer would be,
</span><span>4Al(s) + 3O2(g) --->2 Al2O3(s)
</span>
I hope this helps.
3 0
3 years ago
Other questions:
  • Max discovered a beaker full of transparent liquid in the science lab. He hypothesized that since the liquid is transparent like
    13·1 answer
  • What is the atomic radi for Cs and Cs+1​
    6·1 answer
  • Is electrons gained or lost when a rod becomes positively charged after it is rubbed with a dry silk cloth?
    13·1 answer
  • This human cause process is called ____ and can drastically increase the natural process _____​
    11·2 answers
  • Technetium has a half-life of six hours. If you obtain 100g of a pure technetium sample, after 18 hours how much of the pure sub
    14·1 answer
  • What is the formula for the molecular compound disulfur decafluoride?
    7·2 answers
  • Please help thankyou
    15·1 answer
  • Ideal gasses
    5·1 answer
  • What are periods on the periodic table? How many are there?
    5·1 answer
  • What are the answers to these?
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!