Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 36m
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

1. Intro to General Chemistry

Density

General Chemistry

1. Intro to General Chemistry

Density

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Multiple Choice

Calculate the number of atoms in a copper rod with a length of 9.85 cm and a radius of 1.05 cm. The density of copper is 8.96 g/cm³. (The volume of a cylinder is V = πr²l.) Express the number of atoms to three significant figures. Assume the molar mass of copper is 63.55 g/mol and Avogadro's number is 6.022 × 10²³ atoms/mol.

6.02 × 10²³ atoms

1.32 × 10²⁴ atoms

2.64 × 10²⁴ atoms

3.96 × 10²³ atoms

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Verified step by step guidance

Calculate the volume of the copper rod using the formula for the volume of a cylinder: \( V = \pi r^2 l \). Substitute the given radius \( r = 1.05 \text{ cm} \) and length \( l = 9.85 \text{ cm} \) into the formula.

Determine the mass of the copper rod using the density formula: \( \text{mass} = \text{density} \times \text{volume} \). Use the given density of copper \( 8.96 \text{ g/cm}^3 \) and the volume calculated in the previous step.

Convert the mass of the copper rod to moles by using the molar mass of copper: \( \text{moles of copper} = \frac{\text{mass of copper}}{\text{molar mass of copper}} \). The molar mass of copper is given as \( 63.55 \text{ g/mol} \).

Calculate the number of atoms in the copper rod by multiplying the moles of copper by Avogadro's number: \( \text{number of atoms} = \text{moles of copper} \times 6.022 \times 10^{23} \text{ atoms/mol} \).

Express the final result for the number of atoms to three significant figures, as required by the problem statement.