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1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

6. Chemical Reactions & Quantities

Molecular Formula

GOB Chemistry

6. Chemical Reactions & Quantities

Molecular Formula

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Multiple Choice

Cortisol (MW = 362.47 g/mol), a known steroid hormone, is found to contain 69.6% carbon, 8.34% hydrogen, and 22.1% oxygen by mass. What is its molecular formula?

C₂₁H₃₀O₅

C₂₁H₂₆O₅

C₂₈H₄₆O

C₁₈H₂₄O₂

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Verified step by step guidance

Start by determining the mass of each element in 100 g of cortisol based on the given percentages: 69.6 g of carbon, 8.34 g of hydrogen, and 22.1 g of oxygen.

Convert these masses to moles using the molar mass of each element: Carbon (C) is 12.01 g/mol, Hydrogen (H) is 1.008 g/mol, and Oxygen (O) is 16.00 g/mol.

Calculate the number of moles for each element: moles of C = 69.6 g / 12.01 g/mol, moles of H = 8.34 g / 1.008 g/mol, moles of O = 22.1 g / 16.00 g/mol.

Determine the simplest whole number ratio of moles of each element by dividing each by the smallest number of moles calculated in the previous step.

Use the whole number ratio to write the empirical formula, then compare the empirical formula mass to the given molecular weight (362.47 g/mol) to find the molecular formula.