Midterm Review Answers
Chapter 1 pg. 26
- 5.a. A measure of the amount of matter.
b. The amount of space occupied by matter.
6. The proportions of elements in a pure substance or fixed.
7.a. Any characteristic of a substance or material
b. In order to classify unknown materials as members of known groups or subgroups of substances or to identify substances directly.
9. a. A characteristic can be observed or measured without changing identity of the substance.
b. Color, odor, length, size, melting point, and boiling point.
10. a. A property that describes the ability of a substance to undergo changes that alter its identity.
b. Coal to burn and iron to rust.
11. Physical change-substance that does not involve a change in identity
Chemical change-substance converted into other substances
12. a. solids, liquids, gases
b. solid state has definite volume and shape where as liquid has definite volume but takes the shape of its container.
c. A gas has neither definite volume or shape
d. Liquids and gases take the shape of the container
17. Reactants are potassium and oxygen, the products are potassium hydroxide and hydrogen.
19.a. physical because the wood remains wood
b. chemical because the milk changes composition, as signified by the change in flavor
c. physical because the butter remains butter
20 .a. potassium, metal
b. silver, metal
c. silicon, metalloid
d. sodium, metal
e. mercury, metal
f. helium, noble gas
23. a. group 14, period 2
b. 18, 3
c. 6, 4
d. 2, 6
e. 17, 5
f. 11, 6
Chapter 2 pg. 60
- 26. 7.5m3
28. 3.70 x 102 g
29. 0.547 mL
30. 8.82 x 10-4 g
31. 6.03 x 102 mL
32. a. 9.225 x 10-2 km
b. 9.225 x 103 cm
36. a. four
37. 1.1 cm
41.a. 6.730 x 10-4
b. 5.000 00 x 104
c. 3.010 x 10-6
42.a. 0.007 050 g
b. 40 000 500 mg
c. 23 500. ML
43.a. 8.278 x 104 mg
b. 2.5766 x 10-2 kg
c. 6.83 x 10-2 m3
d. 8.57 x 108 m2
Chapter 3 pg. 87
- 1. a. Because all chemical reactions involve the rearrangement of atoms, mass in neither created nor destroyed in such changes
b. Atoms of each element have their own characteristic mass, so compounds consisting of atoms always have the same composition by mass.
c. Only whole atoms combine in chemical compounds, so different compounds between the same two elements must result form the different whole numbers of atoms.
3. a. the smallest particle of am element that retains the chemical properties of that element
b. the nucleus and surrounding electrons
5. Rutherfords atom has not of the mass concentrated at its center in the nucleus. This model resulted from bombarding gold atoms with positively charged particles. Most of the particles went right through the atom, but some actually bounced back.
6. the atomic number
7. a. Atoms of an element that contain the same number of neutrons
8. isotope pro e- neut
si-28 14 14 14
Si-29 14 14 15
Si-30 14 14 16
11. a. helium-4
17. a. 6.94g
17. a. 1.000 mol
c. 1.57x10^3 mol
22. b. 6.05 g
23. b. 1.50X10^23 atoms
28. 0.500 mol
Chapter 4 pg.118
- 3. Frequencies range from 5 x 1014 to 1 x 1015 Hz
Wavelengths range from 400 to 700 nm
4. Red, orange, yellow, green, blue, violet
6.a. Velocity = Wavelength x Frequency
b. Energy = Plancks Constant x Frequency
c. Energy = (Plancks Constant x Velocity) / Wavelength
7.a. Wave theory
b. Particle theory
c. Particle theory
7. Ground State- atoms lowest energy state
Excited State- any energy state that is higher in energy than the atoms ground state
13. a. 1; s
b. 2; s and p
c. 3; s, p and d
d. 14; s, p, d, and f
17. a. 2
d. theoretically 72, but it does not seem to hold more than 32
e. theoretically 98, but it does not seem to hold more than 32
22. a. First main energy level (n=1)
b. Second main energy level (n=2)
c. Third energy level (n=3)
d. Fourth energy level (n=4)
e. Fifth energy level (n=5)
23.a. &Mac221;&Mac223; &Mac221;&Mac223; &Mac221;&Mac223; &Mac221;&Mac223;&Mac221;&Mac223;
1s 2s 2px 2py 2pz
. &Mac221;&Mac223; &Mac221; &Mac221; &Mac221;
3s 3px 3py 3pz
b. &Mac221;&Mac223; &Mac221;&Mac223; &Mac221; &Mac221; &Mac221; .
1s 2s 2px 2py 2pz
c. &Mac221;&Mac223; &Mac221;&Mac223; &Mac221;&Mac223; &Mac221;&Mac223;&Mac221;&Mac223;
1s 2s 2px 2py 2pz
d. &Mac221;&Mac223; &Mac221;&Mac223; &Mac221;&Mac223; &Mac221; &Mac221; .
1s 2s 2px 2py 2pz
31. 7.0 x 1016 Hz
32. 2.35 x 10-16 J
Chapter 17 p. 514
16. 3.6 x 103 J
Chapter 22 p.723
- 4.a. Decreases mass number by 4 and atomic number by 2
b. Increases atomic number by 1, does not change mass number
7.a. 10 n 11 P + 0-1 B
b. 9.a. high-energy electromagnetic radiation Gamma rays are produced when nuclear particles undergo transition in nuclear energy levels.
33.a. 0-1 B
b. 42 He
34. 21084 Po 42 He + 20682 Pb
35. 21084 Po 0-1 B + 21083 Bi
36. 6.25 g
37. 37.44 days
39. 0.938 mg
Chapter 5 P. 155-157
- 1. b. Mendeleev organized the elements according to increasing atomic mass and noticed that similar properties appeared periodically.
c. Mosely discovered that nuclear charge (i.e. atomic number), not atomic mass, should be the basis of organizing the periodic table.
3. Groups of elements exhibit similar chemical properties and behavior.
4. a. Generally the configurations of the outermost electron shells of elements within the same group are the same. There are a number of exceptions to this rule, however, among transition elements.
b. their outer shells are completely filled
8. a. the group one elements
b. Group one elements are very reactive. They react vigorously with water, they re silvery in appearance, and each o soft enough to be cut with a knife.
9. a. group 2 elements
b. the group 2 elements are harder denser and stronger that the group one elements. They also have higher melting points. Group2 elements are less reactive than group1.
11. Transition elements
12. a. The p block consists of non-metals and the right, metalloids on the middle, and metals at the left.
b. The p-block metals are generally harder and denser that the s-block metals but softer and less dense than the d-block metals.
13. a. the group 17 elements
b. the halogens are the most reactive non metals: they react vigorously with most metals to form salts. They are also the most-electronegative elements.
17. a. one half the distance between the nuclei of 2 bonded identical atoms.
b. they decrease
c. as electrons are called to s and p sublevels in the same main energy level the increasing positive charge if the nucleus pulls electrons closer to the nucleus, resulting in decreasing atomic radii.
18. a. they generally increase
b. Down a group, the outer electrons of each element occupy comparable sublevels in successively higher main energy levels farther from the nucleus.
19 a. a charged atom or a charged group of bonded atoms.
b. any process that results in the formation of an ion
c. the energy required to remove one electron form neutral atom on an element
d. the energy required to remove an electron form a 1+ ion
20. a. they increase across the period and decrease down a group
b. Across a period, the increasing nuclear charge more strongly attract electrons in the same energy level and makes them more difficult to remove. Down a group, the electrons to be removed form each successive element are in increasingly higher energy levels farther from the nucleus and are thus more easily removed.
21. a. the energy taken in or given off when an electron is added to an atom
b. Electron affinity values are either negative or positive. A negative sign indicated that energy is given off, a positive sign indicated that energy is taken in.
22. a. a Cation is a positive ion, and anion is a negative ion.
b. Cations are always smaller than the atoms from which they are formed: anion are always larger
23. a. Valence electrons are atomic electrons available to be lost or gained, or shared in formation of chemical compounds.
b. Valence electrons are located in an atoms outermost energy level.
25. a. Electro negativity is the ability of an atom in a chemical compound to attract electrons for other atoms.
b. Fluorine is the most electronegative element and is arbitrarily assigned an electronegativity of 4.0. The values of all other elements are assigned in relation to this value.
28. a. third period, p block, Group 16
b. fifth period, p block, Group 14
c. sixth period, p block, Group 17
30. a. 3d54s2
35. a. Ne, F, O, C, Li, K
b. Li and K would have the highest second ionization energies because in both cases the second electron must come from a completely filled noble-gas electron configuration. Of the two, Li would have the higher second ionization energy because the Li+ ion is smaller than the K+ ion.
Ch 6 pg. 194
- 1. A chemical bond is a link between atoms resulting from the mutual attraction of their nuclei and electrons.
2. The three major types of chemical bonding are ionic, covalent, and metallic. In ionic bonding, large numbers of oppositely charged ions join because of mutual electrical attraction. In covalent bonding, atoms join by sharing electron pairs. In metallic bonding, atoms join through an attraction to a sea of valence electrons.
3. In general, the greater the electronegativity difference between two atoms is, the more ionic the bond between them is.
4. a. Polar refers to bonds that have an uneven distribution of charge.
b. In a polar-covalent bond there is an unequal attraction for the electron pair, resulting in one of the bonded atoms possessing a partial negative charge and the other atom possessing a partial positive charge. In a non-polar covalent bond the electron pair is shared equally by the bonded atoms.
6. A molecule is a neutral group of two or more atoms- usually nonmetals-held together by covalent bonds.
7. a. The distance at which potential energy is at a minimum; bond length is the point at which there is a balance between attraction and repulsion between atoms in a covalent bond.
33. Determine the electronegativity difference, the probable bond type, and the more electronegative atom with respect to bonds formed between the following pairs of atoms.
37. Use electron-dot notation to illustrate the number of valence electrons present in one atom of each of the following elements.
- 24 a. linear, b. trigonal planar, c. tetrahedral,
43 a. trigonal planar, b. bent, c. bent
49 b,b see page 199B
- NH3 Hydrogen bonds, also has dipole dipole and london dispersion forces
PH3 has dipole dipole and london dispersion forces
CH4 weaker london dispersion forces so lower B.P. than C6H6 which also has london dispersion forces but higher mass therefore higher london dispersion forces
- 40 d.163 g
44. a. nitrous acid, +1, +3, -2, b. sulfurous acid +1,+4, -2, c. carbonic acid +1, +4 -2, d. hydroiodic acid
46 a. 30.88 % Na, 47.62 % Cl 21.49% O
- 38. C6H8O7
- empirical formula for C2H4 is CH2 and for C6H6 is CH
- # 38 C6H8O7
- #40 d163 g
- # 44, a nitrous acid +1, +3, -2, b sulfurous acid +1, +4, -2, c carbonic acid +1, +4, -2, d. hydroiodic acid, +1, -1
- #46 a 30.88 % Na, 47.62% Cl, 21.49 % O, b,2.46 % H, 39.07 % S, 58.47 % O
- 4a decrease mass number by 4 and atomic number by two, b, increase atomic number by one but no change in mass number
- 7 a. 1neutron -->1proton + beta,
- 9. high energy EMR,
- 33a. beta,b alpha,
- 34. Po --> alpha + Pb206- 82
- 35. Pb -->beta + Bi 210 83
- 36. 6.25 g
- 37. 37.44 days
- 38. 1/16
- 39. 0.938 mg