Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

3. Chemical Reactions

Combustion Apparatus

General Chemistry

3. Chemical Reactions

Combustion Apparatus

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Multiple Choice

Combustion analysis of 0.326 g of a compound known to contain only C, H, and O produces 0.7160 g CO₂ and 0.3909 g H₂O. A mass spectrum indicates that this compound has a formula mass of 120 g/mol. What is the molecular formula?

C₄H₈O₄

C₃H₈O

C₃H₄O

C₆H₁₆O₂

The molecular formula cannot be determined from the information given.

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Verified step by step guidance

Determine the moles of carbon in the compound by using the mass of CO2 produced. Use the molar mass of CO2 (44.01 g/mol) to find the moles of CO2, and then use the ratio of moles of C to moles of CO2 (1:1) to find the moles of carbon.

Determine the moles of hydrogen in the compound by using the mass of H2O produced. Use the molar mass of H2O (18.02 g/mol) to find the moles of H2O, and then use the ratio of moles of H to moles of H2O (2:1) to find the moles of hydrogen.

Calculate the mass of carbon and hydrogen in the compound using their respective moles and atomic masses (C: 12.01 g/mol, H: 1.008 g/mol). Subtract the sum of these masses from the original mass of the compound to find the mass of oxygen.

Determine the moles of oxygen in the compound by using the mass of oxygen calculated in the previous step and the atomic mass of oxygen (16.00 g/mol).

Find the empirical formula by dividing the moles of each element by the smallest number of moles calculated. Then, determine the molecular formula by comparing the empirical formula mass to the given formula mass (120 g/mol) and adjusting the subscripts accordingly.