1. Seminar: Test 1 Review Freddie Arocho-Perez Kaplan University SC155: Introduction to Chemistry

2. General Information Access Dates: Wednesday, Oct 13 – Tuesday, Oct 26 During the time that the test is available, you may take it anytime you wish and as many times as you want. Only the last submission will be saved and graded. I made it available for more time than I originally noted in the syllabus. The only reason I did this was because I assume most of you may want to work on this test on evenings and weekends.

3. General Information The questions have been formulated by me (Instructor) and the Science Instructional Committee. I did apply this change in order to make the test content more related to our seminars and discussions. The test consists of 30-multiple choice questions. Study Guide sent by e-mail and posted in DocSharing.

4. General Information The test questions will account for reading comprehension, applications, definitions, and mathematical analysis. There will be 9 math-related questions, coming specially from the material included in: – “Seminar: Math Review Session” – “Seminar: Elements, Compounds, and Chemical Reactions” Useful Materials: – Calculator – Periodic Table (see DocSharing for a hand-out) – Conversion Factors (see hand-outs “Metric and English Conversion Factors” and “Math Review: Metric System / Dimensional Analysis” in DocSharing)

5. Practice Question Which of the following element/chemical symbol pairs is incorrectly matched? – Chromium: Cr – Rubidium: Rb – Scandium: S – Argon: Ar – Gold: Au

6. Practice Question Which of the following element/chemical symbol pairs is incorrectly matched? – Chromium: Cr – Rubidium: Rb – Scandium: S – Argon: Ar – Gold: Au

7. Solution: Practice Question From the Periodic Table: – Scandium: Sc – Atomic Number: 21 – Sulfur: S – Atomic Number: 16

8. Practice Question Which of the following statements is incorrect? – All atoms of an element have the same atomic number. – All atoms of an element must have the same mass. – All atoms of an element have the same number of protons. – Atoms of an element may have different numbers of neutrons.

9. Practice Question Which of the following statements is incorrect? – All atoms of an element have the same atomic number. – All atoms of an element must have the same mass. – All atoms of an element have the same number of protons. – Atoms of an element may have different numbers of neutrons.

10. Solution: Practice Question All atoms of an element have the same atomic number = TRUE All atoms of an element must have the same mass = FALSE All atoms of an element have the same number of protons = TRUE – (# Protons = Atomic Number) Atoms of an element may have different numbers of neutrons = TRUE – Isotopes: different forms of an element each having different atomic mass. Isotopes of an element have the same number of protons (the same atomic number) but different numbers of neutrons.

11. Practice Question Which of the following involves chemistry? – automobiles – detergents – cooking – all of the above

12. Practice Question Which of the following involves chemistry? – automobiles – detergents – cooking – all of the above

13. Solution: Practice Question Chemistry is EVERYWHERE!!!!

14. Practice Question Tap water consists of water, sodium and chloride ions, and possibly bacteria, chlorine, and other ingredients. Which choice best defines what tap water is? – a molecule – an element – a mixture – a compound

15. Practice Question Tap water consists of water, sodium and chloride ions, and possibly bacteria, chlorine, and other ingredients. Which choice best defines what tap water is? – a molecule – an element – a mixture – a compound

16. Solution: Practice Question Pure Substance: A sample of matter, either an element or a compound, that consists of only one component with definite physical and chemical properties and a definite composition. Element: Substance consisting of only one type of atom. Compound: Two or more atoms joined together chemically (with bonds). Mixture: Composed of two or more substances, but each keeps its original properties.

17. Practice Question Calculate how many liters of liquid are in a container that has 579 mL of the liquid. (1 L = 1,000 mL) – 5.79 L – 0.0579 L – 0.579 L – 57.9 L

18. Practice Question Calculate how many liters of liquid are in a container that has 579 mL of the liquid. (1 L = 1,000 mL) – 5.79 L – 0.0579 L – 0.579 L – 57.9 L

19. Solution: Practice Question Conversion Factor: 1 L = 1,000 mL Use Dimensional Analysis:

20. Practice Question How many grams are contained in 3.20 pounds? (1 pound = 453.6 g) – 678.2 g – 964.3 g – 1,322.2 g – 1,451.5 g

21. Practice Question How many grams are contained in 3.20 pounds? (1 pound = 453.6 g) – 678.2 g – 964.3 g – 1,322.2 g – 1,451.5 g

22. Solution: Practice Question Conversion Factor: 1 pound = 453.6 g Use Dimensional Analysis:

23. Practice Question Which component of the atom has no charge? – electrons – protons – neutrons – all components have a charge

24. Practice Question Which component of the atom has no charge? – electrons – protons – neutrons – all components have a charge

25. Solution: Practice Question Sub-atomic Particles: – Protons: Positive (+) Charge – Electrons: Negative (-) Charge – Neutrons: Neutral (0) Charge Center of the Atom: – Protons – Neutrons Surrounding the Center of the Atom: – Electrons

26. Practice Question Which of the following is an example of a chemical property of water? It – boils at 100 C. – is transparent. – has no odor. – reacts with calcium.

27. Practice Question Which of the following is an example of a chemical property of water? It – boils at 100 C. – is transparent. – has no odor. – reacts with calcium.

28. Solution: Practice Question A chemical property of a substance is how the substance reacts with other substances and what new products may form. A physical property describes the substance’s characteristics. An example of a chemical property is how substances react to heat (flammability) or acid. An example of a physical property is the melting point or density of a substance.

29. Solution: Practice Question Water: – Physical properties: it melts at 0 C, boils at 100 C (at sea level), transparent, odorless, density is 1.0 g/cm 3. – Chemical properties: reacts with some metals like Calcium quickly, reacts with other metals slowly to form rust. Doesn’t burn. Salt: – Physical: white, crystalline, high melting point. – Chemical: doesn’t burn, doesn’t react with acid.

30. Practice Question Which of the following is an example of a physical property of hydrogen? It – is less dense than air. – reacts with oxygen. – is highly flammable. – forms hydrochloric acid.

31. Practice Question Which of the following is an example of a physical property of hydrogen? It – is less dense than air. – reacts with oxygen. – is highly flammable. – forms hydrochloric acid.

32. Mass Relations Atomic Mass vs. Molecular Mass: – Atomic Mass: Mass of the atom of an element. – Molecular Mass: Mass of a molecule; Sum of the atomic masses of the atoms in a molecule. – amu: atomic mass units. From the Periodic Table, we can obtain atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu

33. Mass Relations Atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu Calculate the molecular mass of H 2 O: H: 2 atoms X 1.008 = 2.016 O: 1 atom X 16.00 = 16.00 Total: 18.016 ~ 18.02 amu

34. Mass Relations Atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu Calculate the molecular mass of CO 2 : C: 1 atom X 12.01 = 12.01 O: 2 atoms X 16.00 = 32.00 Total: 44.01 amu

35. Practice Question Atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu Calculate the molecular mass of CH 4 :

36. Practice Question Atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu Calculate the molecular mass of CH 4 : C: 1 atom X 12.01 = 12.01 H: 4 atoms X 1.008 = 4.032 Total: 16.042 ~ 16.04 amu

37. Practice Question 48 C is approximately the same as – 341 K. – 321 K. – 285 K. – 205 K. – 158 K.

38. Practice Question 48 C is approximately the same as – 341 K. – 321 K. – 285 K. – 205 K. – 158 K.

39. Solution: Practice Question This is a temperature conversion problem: K = C + 273.15 K = 48 + 273.15 = 321.15 = 321(rounded)

40. Practice Question 120.0 C is approximately the same as – 100 F. – 159 F. – 207 F. – 248 F. – 306 F.

41. Practice Question 120.0 C is approximately the same as – 100 F. – 159 F. – 207 F. – 248 F. – 306 F.

42. Solution: Practice Question This is a temperature conversion problem F = (1.8 x C) + 32 F = (1.8 x 120.0) + 32 = 216 + 32 = 248(rounded)

43. Practice Question Atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu Calculate the molecular mass of K 2 SO 4 :

44. Practice Question Atomic masses: C = 12.01 amu Ca = 40.08 amu H = 1.008 amu K = 39.10 amu P = 30.97 amu S = 32.07 amu O = 16.00 amu Calculate the molecular mass of K 2 SO 4 : K: 2 atoms X 39.10 = 78.20 S: 1 atom X 32.07 = 32.07 O: 4 atoms X 16.00 = 64.00 Total: 174.27 amu