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

Empirical Formula

General Chemistry

3. Chemical Reactions

Empirical Formula

Previous problemNext problem

Struggling with General Chemistry?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

An unknown compound contains only carbon, hydrogen, and chlorine. Using combustion analysis, you burned 22.56 mg of the sample and collected 7.11 mg of H2O and 52.93 mg of CO2. What is the empirical formula of this compound?

CH2Cl

C2H3Cl

C2H4Cl

C3H6Cl2

Previous problemNext problem

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 convert the mass of CO2 to moles, and then use the stoichiometry of the reaction to find the moles of carbon. Since each mole of CO2 contains one mole of carbon, the moles of carbon are equal to the moles of CO2.

Calculate 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 convert the mass of H2O to moles, and then use the stoichiometry of the reaction to find the moles of hydrogen. Since each mole of H2O contains two moles of hydrogen, multiply the moles of H2O by 2 to get the moles of hydrogen.

Determine the mass of carbon and hydrogen in the original sample using their respective moles and atomic masses (carbon: 12.01 g/mol, hydrogen: 1.008 g/mol). Subtract the combined mass of carbon and hydrogen from the total mass of the sample to find the mass of chlorine.

Calculate the moles of chlorine in the compound using the mass of chlorine obtained in the previous step and the atomic mass of chlorine (35.45 g/mol).

Determine the empirical formula by finding the simplest whole number ratio of moles of carbon, hydrogen, and chlorine. Divide the moles of each element by the smallest number of moles calculated in the previous steps to obtain the ratio, and use these ratios to write the empirical formula.