University:
Carleton College
Course:
CHEM 122 | Introduction to Chemistry
Academic year:

2022
Views:

494

Pages:

10
Author:

Amel S.

Honors Chemistry Semester 1 Review!!! 1. Describe the two categories of matter and provide 2 examples of each. PURE SUBSTANCE: matter with a uniform and unchanging composition. Ex: compound (NaCl, C₁₂H₂₂O₁₁), element (Fe, Al) MIXTURE: 2 or more substances that combine physically 2. Describe the properties that can be used to identify matter and provide 2 examples of each. PHYSICAL PROPERTY: can be observed or measured without changing the substance's composition (density, color, odor, hardness, mp/bp) CHEMICAL PROPERTY: the ability/inability of a substance to combine with or change into another substance (rusting, combustible) Explain the law of conservation of mass. Mass is neither created nor destroyed in chemical reactions! 4. 106.5 g of HCl is reacted with an unknown amount of NH₃ to produce 157.7 g of NH₄Cl. According to the law of conservation of mass, how many grams of NH₃ reacted? HCl + NH₃ → NH₄Cl 106.5 g + ? g = 157.7 g ? g = 51.2 g NH₃ 5. Atomic Structure Determine whether the statements describe Protons (p⁺), Electrons (e⁻), Neutrons (n⁰), or Nucleus (N). There may be more than one answer. a. Composes the main volume of an atom: e⁻ b. Found in the nucleus: p⁺, n⁰ c. Most dense part of the atom: N d. Mass of 1 amu: p⁺, n⁰ e. Identifying characteristic of an atom: p⁺ f. Smallest mass: e⁻ 6. Explain the following concepts. Then complete the table. a. Atomic number: number of protons b. Mass number: total number of protons and neutrons c. Ion vs. atom: same # of protons and different # of electrons Element | Isotopic Symbol | Atomic # | Mass # | # of protons | # of Neutrons | # of Electrons ---|----|----|----|----|----|----| Scandium | ⁴⁵Sc | 21 | 44 | 21 | 23 | 21 Magnesium | ²⁴Mg | 12 | 24 | 12 | 12 | 12 Lithium ion | ⁷Li⁺ | 3 | 7 | 3 | 4 | 2 Potassium atom | ³⁹K | 19 | 39 | 19 | 20 | 19 Iodine ion | ¹²⁷I⁻ | 53 | 127 | 53 | 74 | 54 Bromine ion | ⁸⁰Br⁻ | 35 | 80 | 35 | 45 | 36 7. What is an isotope? Atoms with the same # of p⁺ and different # of n⁰ 8. What does an isotopic symbol like the one below tell us? A X Z Element: X Atomic number: Z Mass number: A 9. What is the average atomic mass, in amu, for element X? | Isotope | Mass of the Isotope (amu) | Percent Abundance | |---|---|---| | X-6 | 6.015 | 7.59% | | X-7 | 7.016 | 92.41% | X-6: 6.015 x 0.0759 = 0.456 X-7: 7.016 x 0.9241 = 6.48 X = 6.94 amu 10. Identify the element in #9. Lithium Quantum Theory 11. Complete the following table: | Principle Energy Level (n) | Number of Sublevels | Types of Orbitals | |---|---|---| | 1 | 1 | s | | 2 | 2 | s, p | | 3 | 3 | s, p, d | | 4 | 4 | s, p, d, f | 12. How do we calculate the number of orbitals in each principal energy level? # orbitals = n² ex: 2nd principal energy level: 2² = 4 orbitals 13. Draw the following orbitals: i. s-orbital: [Image of an s-orbital] ii. p-orbital: [Image of a p-orbital] 14. How many orbitals does each sublevel contain? s: 1 p: 3 d: 5 f: 7 15. Explain the Pauli Exclusion Principle. A maximum of 2 electrons can occupy a single orbital, but only if the electrons have opposite spins. 16. Explain what the coefficient, letter, and superscript stand for when describing electrons in atoms. Ex. 1s² electrons 2 principle energy level s sublevel/orbital 1 electron 2 electrons 17. Write electron configurations and orbital diagrams for the following elements: a. Mn: 1s²2s²2p⁶3s²3p⁶3d⁵4s² b. Br: 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁵ 18. Write the noble gas configuration for the following elements: a. P: [Ne]3s²3p³ b. Br: [Ar]4s²3d¹⁰4p⁵

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