Midterm Review U1-6

Unit 1 - Introduction to Chemistry

1. Scientific Method Steps

• Identification of a problem or question

• Formulating a hypothesis

• Conducting experiments to test the hypothesis

• Analyzing data and drawing conclusions

• Communicating results

2. Match Column A to Column B

• A: refers to physical characteristics (e.g., color, odor) - b. qualitative data

• B: refers to mass, volume, temperature measurements - c. quantitative data

• C: controlled variable by the experimenter - d. independent variable

• D: changes based on the controlled variable - e. dependent variable

3. Definitions

• Chemistry: The study of matter, its properties, and how it interacts with other matter.

• Matter: Anything that has mass and occupies space.

4. State of Matter Identification

• a. Gas: Indefinite volume and shape, compressible, low density, particles can move freely.

• b. Solid: Definite volume and shape, not compressible, high density, particles cannot move, just vibrate.

• c. Liquid: Definite volume, takes the shape of its container, slightly compressible, less dense than solids, particles can slide past each other.

5. Chemical vs Physical Change

• a) Melting snow - Physical Change

• b) Boiling water - Physical Change

• c) Rusting metal - Chemical Change

• d) Sugar dissolving in water - Physical Change

• e) Burning paper - Chemical Change

• f) Baking cookies - Chemical Change

6. Chemical vs Physical Property

• a) Reacts with oxygen - Chemical Property

• b) Melting point is 183 °C - Physical Property

• c) Density is 2.27 g/mL - Physical Property

• d) Orange-red color - Physical Property

• e) Catches on fire easily - Chemical Property

• f) Freezing point - Physical Property

• g) Smells like burning paper - Physical Property

• h) Burns when oxygen is added - Chemical Property

7. Element, Compound, or Mixture

• a) Carbon dioxide - Compound

• b) Sugar solution - Mixture (Homogeneous)

• c) Oxygen - Element

8. Properties Classification

• Extensive Properties: Depend on the amount of matter (e.g., mass, volume).

• Intensive Properties: Do not depend on the amount of matter (e.g., density, boiling point).

9. SI Units

• a. Length: Meter (m)

• b. Mass: Kilogram (kg)

• c. Volume: Liter (L) or cubic meter (m³)

• d. Temperature: Kelvin (K)

10. Rounding Significant Figures

• a. 12.555 -> 12.56

• b. 1.0009 -> 1.001/,, Figures

• a. 12.783 456 -> 2 significant figures -> 13

• b. 12.783 456 -> 5 significant figures -> 12.783

• c. 12.783 456 -> 6 significant figures -> 12.7835

• d. 12.783 456 -> 7 significant figures -> 12.7835

12. Rounding Atomic Mass

• a. 120.752416 -> 3 significant figures -> 120

• b. 120.752416 -> 4 significant figures -> 120.8

• c. 120.752416 -> 5 significant figures -> 120.75

• d. 120.752416 -> 7 significant figures -> 120.7524

Unit 2 - Dimensional Analysis

13. Dimensional Analysis Examples

• a) 1.45 m = 145 cm

• b) 325 g = 0.325 kg

Unit 3 - Atomic Structure

14. Subatomic Particles

• Protons: Mass: 1 amu, Charge: +1, Location: Nucleus

• Neutrons: Mass: 1 amu, Charge: 0, Location: Nucleus

• Electrons: Mass: 0 amu, Charge: -1, Location: Outside nucleus

15. Atomic Information

• Atomic Number: Represents the number of protons in an element.

• Mass Number: Represents the total number of protons and neutrons in an atom.

• Isotopes: Atoms of the same element with different numbers of neutrons.

• Atomic Mass: The weighted average of all isotopes of an element.

16. Isotope Calculations

• Carbon: 12.000 amu (98.89% abundance), 13.003 amu (1.11% abundance)

• Nitrogen: 14.003 amu (99.63% abundance), 15.000 amu (0.37% abundance)

• Oxygen: 15.995 amu (99.759% abundance), 16.995 amu (0.037% abundance), 17.999 amu (0.204% abundance)

Unit 4 - Electron Configurations

17. Orbital Structures and Configurations

• Types of Sublevels: s, p, d, f

• Maximum Electrons: 1s (2), 2p (6), 3d (10), 4f (14)

18. Orbital Diagrams

• Oxygen: 1s² 2s² 2p⁴

• Neon: 1s² 2s² 2p⁶

19. Electron Configurations for Cl and Cl-1

• Cl: 1s² 2s² 2p⁶ 3s² 3p⁵

• Cl-1: 1s² 2s² 2p⁶ 3s² 3p⁶ (Filled valence shell)

• Valence Electrons in Neutral Cl: 7

20. Electron Configurations for Sr and Sr+2

• Sr: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s²

• Sr+2: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶

• Isoelectronic with: K (Potassium)

Unit 5 - Periodic Trends

21. Periodic Table Mappings

• Group: Column on the periodic table

• Period: Row on the periodic table

• Metals: Generally shiny conductors.

• Transition Elements: Groups 3 to 12.

22. Properties of Metals

• Good conductors of heat and electricity

• Malleable and ductile

• High melting and boiling points

• Lustrous (shiny)

• Tend to lose electrons in reactions

23. Trends in Atomic and Ionic Size

• Ionization Energy: Energy required to remove an electron from an atom

• Trends: Increases across a period, decreases down a group

• Electronegativity: Tendency of an atom to attract electrons in a bond

• Trends: Increases across a period, decreases down a group

24. Valence Electrons and Electron Dot Structure

• Calculate number of valence electrons based on the group number.

• Draw electron dot structures to predict ionic compounds and molecular polarity.

Conclusion

• This review covers fundamental concepts in Chemistry, including states of matter, chemical properties, atomic structure, and periodic trends essential for understanding basic chemistry principles.