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

Stoichiometry

General Chemistry

3. Chemical Reactions

Stoichiometry

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Multiple Choice

How many grams of alum (KAl(SO4)2·12H2O) can be produced from 20.0 g of aluminum (Al) when the reaction proceeds with 100% yield?

23.7 g

47.3 g

94.6 g

189.2 g

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Verified step by step guidance

Start by writing the balanced chemical equation for the reaction. The reaction involves aluminum reacting with potassium sulfate and sulfuric acid to form alum (KAl(SO4)2·12H2O). The balanced equation is: 2 Al + 2 K2SO4 + 6 H2SO4 + 24 H2O → 2 KAl(SO4)2·12H2O.

Calculate the molar mass of aluminum (Al). The atomic mass of aluminum is approximately 26.98 g/mol.

Determine the number of moles of aluminum you have. Use the formula: \( \text{moles of Al} = \frac{\text{mass of Al}}{\text{molar mass of Al}} \). Substitute the given mass of aluminum (20.0 g) and its molar mass to find the moles.

Using the stoichiometry from the balanced equation, find the moles of alum (KAl(SO4)2·12H2O) that can be produced. According to the equation, 2 moles of Al produce 2 moles of alum, so the moles of alum will be equal to the moles of Al.

Calculate the mass of alum produced using its molar mass. First, find the molar mass of KAl(SO4)2·12H2O by adding the atomic masses of all atoms in the formula. Then use the formula: \( \text{mass of alum} = \text{moles of alum} \times \text{molar mass of alum} \) to find the mass.