chemistry

Chem 101 – Final Exam

Select Response Write the best response to each question in the answer table. ( 1 pt each – 25 pts)

1. An atom has only two stable isotopes. One stable isotope has a mass number of 10 and the other has a mass number of 11.

Which of the following could be the atomic mass of the element?

a. 9.5 b. 10.8 c. 11.7 d. 12.4

2. Which electron configuration is possible for a nitrogen atom in the excited state?

a. 1s22s5 b. 1s22s12p4 c. 1s22s22p3 d. 1s22s22p2

3. Which orbital notation represents the outermost energy level (valence electrons) of oxygen in the ground state?

s p

a.   

b.   

c.    

d.    

4. Consider the elements in Group-15. In order of increasing atomic number, which sequence occurs?

a. nonmetal → metalloid → metal b. metal → metalloid → nonmetal

c. metalloid → metal → nonmetal d. metal → nonmetal → metalloid

5. Which lists atoms in order of increasing atomic radii?

a. Li, Be, B, C b. Sr, Ca, Mg, Be c. F, Cl, Br, I d. Sc, Ti, V, Cr

6. Which sequence represents a correct order of historical developments leading to the modern model of the atom?

a. the atom is a hard sphere → most of the atom is empty space → electrons exist in orbitals outside the nucleus

b. the atom is a hard sphere → electrons exist in orbitals outside the nucleus → most of the atom is empty space

c. most of the atom is empty space → electrons exist in orbitals outside the nucleus → the atom is a hard sphere

d. most of the atom is empty space → the atom is a hard sphere → electrons exist in orbitals outside the nucleus

7. In which of the following orbitals would an electron have the highest energy?

a. 3p b. 2p c. 3s d. 4s

8. The elements within a family have similar properties because they have similar .

a. atomic masses b. isotopes

c. number of filled energy levels d. valence electron configurations

9. Substances and their boiling points are listed. Which substance has the stronger intermolecular force of attraction?

a. H2S, -60 ºC b. Br2, 59 ºC c. C2H5OH, 78 ºC d. H2O, 100 ºC

10. Which is a covalent compound?

a. Kr b. LiOH c. N2O4 d. NaI

11. Which statement best describes why atoms bond?

a. Atoms want to be stable. b. Bond formation forms a lower energy state.

c. Bond formation creates a higher energy state. d. Bonds are needed to build molecules.

12. In the reaction: __NaI + __Cl2 → __NaCl + __I2, sodium iodide is a .

a. coefficient b. product c. reactant d. subscript

Chem 101 – Final Exam 13. What is the empirical formula for a compound with the molecular formula C4H12N2?

a. CHN b. CH3N c. C2H6N d. C4H12N2

14. How many particles are in one mole of any substance?

a. 6.022 x 1022 b. 6.022 x 1023 c. 6.022 23 d. 6.022 x e23

15. A sample contains 1 mol of Cu and another sample contains 1 mol of Fe. Which statement is true?

a. Both samples have the same number of atoms, since they both contain 1 mol.

b. Both samples have the same mass, since they both contain 1 mol.

c. The Cu sample has a smaller mass, since the atomic mass of Cu is more than that of Fe.

d. The Fe sample contains fewer atoms, since the atomic mass of Fe is less than that of Cu.

16. Consider the reaction between calcium oxide, CaO, and carbon, C: CaO + 3C → CaC2 + CO.

How many moles of carbon, C, are needed to react completely with 2.0 moles of calcium oxide, CaO?

a. 3.0 moles b. 6.0 moles c. 12.0 g d. 24.0 g

17. A flask contains a 1.00 mole of neon gas and 2.00 moles of argon gas. If the total pressure of the gases is 6.0 atm, then

what is the partial pressure of the argon gas?

a. 1.0 atm b. 4.0 atm c. 3.0 atm d. 12.0 atm

18. What temperature is required to maintain 2.50 mol of hydrogen gas, H2, at 250 torr with a volume of 2.00 L?

a. 3.21 K b. 24.1 K c. 2440 K d. 12,500 K

19 - 20 Refer to the following gases at 0˚C and 1 atm.

a. Ne b. Xe c. CO2 d. CO

19. Which gas moves at a speed closest to that of N2 molecules at STP?

20. Which gas has the greatest density?

21. A 220.0 mL sample of helium gas is in a cylinder with a movable piston at 105 kPa and 275 K. The piston is pushed in

until the volume is 95.0 mL, and the temperature rises to 310 K. What is the new pressure of the gas?

a. 216 kPa b. 274 kPa c. 75,400 kPa d. 2.07 x 107 kPa

22. What is the density of the carbon dioxide gas, CO2, in this room? Assume 20.0 °C and 1.00 atm of pressure.

a. 0.0181 g/L b. 1.83 g/L c. 26.8 g/L d. 44.01g/L

23. Given the reaction at equilibrium: H2(g) + Br2(g) ⇌ 2 HBr(g). The rate of the forward reaction is constant and ____.

a. greater than the rate of the reverse reaction b. less than the rate of the reverse reaction

c. the rate of the reverse reaction is constant d. independent of the rate of the reverse reaction

24. Which refers to a substance that is a proton, H+, donor?

a. acid b. base c. amphoteric d. amphiprotic

25. Which of the following statements is true of an acidic solution?

a. pH > 7 b. pH < 7 c. high [H1+]. d. low [OH1-]

Chem 101 – Final Exam

Select Response Answer Table Write the letter of the best response in the space. (25 pts)

1. 6. 11. 16. 21.

2. 7. 12. 17. 22.

3. 8. 13. 18. 23.

4. 9. 14. 19. 24.

5. 10. 15. 20. 25.

Brief Constructed Response Answer each question completely and thoroughly. 3 pts each – 75 pts total

26 - 27

26. Draw the ground state energy level diagram

of sulfur, S.

27. Write the corresponding electron configuration.

28 - 30

When a student places 35.8 g of a metal at 100.0 °C into 28.5 g of water at 18.0 °C

the temperature of the water increases to 37.3 °C. The specific heat of water is 4.184 𝐽

𝑔∙℃ .

28. Calculate the heat absorbed by the water. 29. Calculate the heat released by the metal into

the water. (heat flow is equal but opposite)

30. Calculate the specific heat of the metal.

Chem 101 – Final Exam

31. What is a shared pair of electrons between two nonmetal atoms?

32. What is the attraction of a cation, typically a metal, with an anion, typically a nonmetal?

33. What type of elements are described as atoms within a sea of loosely held valence electrons?

34. In the compound HF, are the electrons in the H–F bond more attracted to the H or to the F? Explain.

35. Draw the Lewis Structure of formaldehyde, CH2O.

36 - 38. State the geometry AND polarity of each molecule:

36. CH4

37. C2H4

38. NH3

39. a. In a decomposition reaction, if you begin with a total mass of 15.0 g,

what is the total amount of products formed?

b. What is the law that explains the correct response to part-a?

40 – 41 Balance each equation AND state the type of reaction in the blank.

40. __ H2CrO4 + __ Fe → __Fe2(CrO4)3 + __H2

41. __AlCl3 + __H2CO3 → __HCl + __Al2(CO3)3

42. How many moles of water are in 25.0 g of H2O?

43. Consider: 2CO (g) + O2 (g) → 2 CO2(g). How many moles of CO (g) react with 10.8 moles of O2(g) in this reaction?

Chem 101 – Final Exam

44. What is the energy needed to start a chemical reaction?

45. Fully define each of the following terms

a. acid

b. base

c. amphoteric (amphiprotic)

46 – 48 Identify a molecule as an acid or a base or amphiprotic/amphoteric, and then give the formula for the conjugate base or acid.

IF amphiprotic, you will write BOTH the conjugate acid AND base

46. HNO3

47. CO3 2-

48. HSO4 1-

49. If a solution has a hydrogen ion concentration of 2.2 x 10-5 M, then what is the pH of the solution?

You must show work for full credit.

50. If a solution has a pOH of 8.2 what is the pH? You must show work for full credit.