Midterm Exam2 takehome PDF

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General chemistry practice questions for the ACS Exam...

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1. What is the name of Mn(SO4)2? (A) magnesium sulfate (B) manganese sulfate

(C) manganese(II) sulfate (D) manganese(IV) sulfate

2. In an ionic compound with the formula unit XCl2, which is the best choice for the identity of X? (A) aluminum (B) sodium (C) adamantium (D) strontium

3. On the basis of lattice energy, which salt is predicted to have the lowest melting point? (A) CaF2 (B) CaI2 (C) KF (D) KI

4. Chlorine occurs naturally (on Earth) as a mixture of two isotopes. One isotope has a mass of 34.97 amu and a relative abundance of 75.78%. What is the mass of the other isotope (with relative abundance 24.22%)? (A) 34.45 amu (B) 37.95 amu (C) 36.95 amu (D) 39.22 amu

5. Which pair of elements both have similar chemical properties to lithium? (A) Se, Te (B) N, Br (C) Rb, Cs (D) Be, B

6. In what respect does an atom of magnesium differ from a magnesium ion (Mg2+)? (A) The ion has a more stable electronic arrangement than the atom. (B) The positive charge on the nucleus of the ion is two units greater than the nuclear charge on the atom. (C) The ion has two more protons than the atom. (D) The ion will react more readily with free Cl2. (E) The ion has two more planetary electrons than the atom.

7. A certain atom has the symbol 14873Px. What does this symbol tell about an atom of the element? (A) It has 148 electrons. (B) It has a valence of 4. (C) It has 221 protons in the nucleus. (D) It has 75 neutrons in the nucleus. (E) Its atomic mass is 73 u.

8. The atomic mass of an element is 32.07 u and its atomic number is 16. The number of protons contained in the nucleus of an atom of this element is (A) 16 (B) 31 (C) 32 (D) 48

9. The atomic mass of an element is 32.07 u and its atomic number is 16. The element forms a mononuclear ion. The ion will most likely have a charge of (A) 1– (B) 2– (C) 3+ (D) 1+ 10. The nucleus of which atom contains seven neutrons? Atom A

n=1

n=2

n=3

Mass = 24, Z = 12

2e

8e

2e

Atom B

n=1

n=2

n=3

M = 15, Z = 7

2e

5e

Atom C

n=1

n=2

M = 17, Z = 10

2e

8e

Atom D

n=1

n=2

M = 7, Z = 3

2e

1e

n=3

n=3

Atom E

n=1

n=2

n=3

M = 34, Z = 17

2e

8e

7e

(A) A (B) B (C) C (D) D (E) E

11. Four samples of equal masses are present. Which sample contains the least number of atoms? (A) Cl2 (g) (B) Cu (s) (C) Cu (g) (D) He (g)

12. Which is the most complete and best description of a covalent bond? (A) a system of two nuclei with a pair of electrons located exactly midway between both nuclei (B) the attractive force between two atoms of opposite charge (C) a donor bond in which one atom donates an unshared pair to the other (D) a system of two nuclei where each atom donates one electron to the other atom, thus forming a bond

13. In which compound are the bonds best characterized as covalent? (A) CSe2 (B) NiCl2 (C) SrF2 (D) ZrO 14. How many moles of potassium ions are present in 53.0 g of K3PO4? (A) 0.0832 mol K+ (B) 0.749 mol K+ (C) 0.250 mol K+ (D) 1.36 mol K+

15. What is the mass of N atoms present in 1.37 x 1017 molecules of N2O? (A) 1.45 x 10−7 g (B) 1.00 x 10−5 g (C) 6.37 x 10−6 g

(D) 1.27 x 10−5 g

16. What is the energy of a photon with a wavelength of 486 nm? (A) 3.22 x 10−31 J (B) 1.07 x 10−19 J (C) 4.09 x 10−28 J (D) 4.09 x 10−19 J

17. To what element does the ground state electron configuration 1s2 2s2 2p6 3s2 3p5 correspond? (A) Br (B) Cl (C) Mn (D) P

18. What is the ground electron configuration for Fe3+ ion? (A) [Ar]4s2 3d3 (B) [Ar]3d5 (C) [Ar]4s1 3d4 (D) [Ar]4s2 3d5 19. Which ion has the largest radius? (A) F− (B) Mg2+ (C) Na+ (D) O2−

20. Which atom has the largest first ionization energy? (A) Mg (B) S (C) Si (D) Sr

21. How many non-bonding pairs of electrons are on the central atom in BrF3? (A) 0 (B) 1 (C) 2 (D) 3

22. Which molecule has a tetrahedral geometry about the central atom? (A) SiF4 (B) PF4 (C) PF3 (D) XeF4

23. What is the formal charge on an oxygen atom in carbon monoxide? (A) −1 (B) −2 (C) 0 (D) +1

24. When comparing a carbon-carbon single bond to a carbon-carbon double bond, the single bond is... (A) longer and stronger (B) longer and weaker (C) shorter and stronger (D) shorter and weaker

25. What is the hybridization of the oxygen atom in water? (A) 1s2 2s2 2p4 (B) sp (C) sp2 (D) sp3 26. Electrons in a polar covalent bond are (A) shared equally (B) unpaired (C) shared unequally (D) gained

27. What is the molar concentration of a 3.50 x 102 mL solution that contains 5.43 g of KCl? (A) 0.208 M (B) 4.81 M (C) 15.5 M (D) 2.08 M

28. What volume of 10.2 M HCl is required to prepare 50.0 mL of a 0.500 M HCl solution? (A) 0.510 mL (B) 4.90 mL (C) 2.45 mL (D) 49.0 mL

29. How many moles of Al2O3 can be produced by the complete reaction of 13.35 g of Al? 4 Al (s) + 3 O2 (g) → 2 Al2O3 (s) (A) 0.2474 mol (B) 0.4948 mol (C) 0.9896 mol (D) 6.675 mol

30. When 5.60 g of CaF2 reacted with excess H2SO4, 1.73 g HF was obtained. What is the percent yield? (A) 30.9% (B) 49.8% (C) 51.3% (D) 60.3%

31. What is the oxidation number for manganese in Ca(MnO4)2? (A) −4 (B) +2 (C) +4 (D) +7

32. The reaction Cl2 (g) → 2 Cl (g) is (A) exothermic because breaking bonds requires energy (B) exothermic because breaking bonds releases energy (C) endothermic because breaking bonds requires energy (D) endothermic because breaking bonds releases energy

33. How much heat is produced in the reaction of propane with oxygen that produces 5.00 g of CO2? (A) 757 kJ (B) 740 kJ (C) 252 kJ (D) 84.1 kJ

34. Consider the reaction 2 Fe3+ (aq) + 2 I–(aq) → 2 Fe 2+ (aq) + I2 (aq) Which statement is true for the reaction? (A) Fe3+ is oxidized. (B) Fe3+ increases in oxidation number. (C) Fe3+ is reduced. (D) I–is reduced.

35. Which isoelectronic ion is the smallest in size? (A) Al3+ (B) Na+ (C) F– (D) O2–

36. Which ion has the largest radius?

(A) Cl– (B) F– (C) K+ (D) Ca2+

37. An amino acid has a molar mass of 776.9 g·mol–1 and contains 65.34% iodine by mass. What is the number of iodine atoms per molecule of amino acid? (A) one (B) three (C) four (D) five 38. 100 J of energy as heat is transferred to equal mass samples of four metals at the same initial temperature. Which metal reaches the highest temperature? The specific heat of each metal is given in () with units of J g–1 K–1 (A) aluminum (0.902) (B) gold (0.129) (C) copper (0.385) (D) iron (0.450)

39. What is the enthalpy change for this reaction? 2 CO + O2 → 2 CO2 Use the following table of bond dissociation enthalpies (kJ/mol) C≡O

1070

C=O

800

C−O

351

O=O

499

O−O

142

(A) −1039 kJ (B) 561 kJ (C) −561 kJ (D) 1039 kJ...