CHEM 1123 - EXAM 1
An atom of (15)O contains ________ neutrons. a. 7 b. 8 c. 23 d. 15 e. 9
a
An atom of 15N contains ________ protons. a. 7 b. 15 c. 8 d. 10 e. 22
a
In the symbol shown below, x = ________. (14/x)C a. 6 b. 7 c. 12 d. 13 e. not enough information to determine
a
Isotopes are atoms that have the same ________ but differing ________. a. atomic numbers, mass numbers b. mass numbers, charges c. atomic masses, charges d. mass numbers, atomic numbers e. charges, atomic masses
a
The correct result (indicating the proper number of significant figures) of the following addition is ________. 12 + 1.2 + 0.12 + 0.012 = ________. a. 13 b. 13.3 c. 13.33 d. 13.332 e. none of the above
a
The law of constant composition says ________. a. that the composition of a compound is always the same b. that all substances have the same composition c. that the composition of a heterogeneous mixture is always the same d. that the composition of a homogeneous mixture is always the same e. that the composition of an element is always the same
a
There are ________ protons, ________ electrons, and ________ neutrons in an atom of (131/54)Xe. a. 54, 54, 77 b. 54, 54, 131 c. 54, 77, 131 d. 131, 131, 131 e. 131, 131, 77
a
What is the volume (in cm3) of a 18.9 g piece of metal with a density of 19.6 g/cm3? a. 0.964 b. 6.65 c. 19.5 d. 0.425 e. none of the above
a
Which combination of protons, neutrons, and electrons is correct for the isotope of copper, (63/29)Cu? a. 29 p+, 34 n°, 29 e- b. 34 p+, 34 n°, 29 e- c. 63 p+, 29 n°, 63 e- d. 29 p+, 29 n°, 63 e- e. 34 p+, 29 n°, 34 e-
a
Which one of the following is not one of the postulates of Dalton's atomic theory? a. Atoms are composed of protons, neutrons, and electrons. b. Compounds are formed when atoms of more than one element combine; a given compound always has the same relative number and kind of atoms. c. Each element is composed of extremely small particles called atoms. d. All atoms of a given element are identical; the atoms of different elements are different and have different properties. e. Atoms of an element are not changed into different types of atoms by chemical reactions: atoms are neither created nor destroyed in chemical reactions.
a
________ and ________ reside in the atomic nucleus. a. Protons, neutrons b. Protons, electrons c. Electrons, neutrons d. Neutrons, only neutrons e. none of the above
a
An object measuring 30.0 inches will have a length of ________ centimeters. a. 11.8 b. 76.2 c. 0.0847 d. 2.54 e. 0.0131
b
Round the number 3456.5 to two significant figures. a. 3400.0 b. 3500 c. 3000.0 d. 3000 e. 3400
b
The law of constant composition applies to ______. a. homogeneous mixtures b. compounds c. solids d. solutions e. heterogeneous mixtures
b
The symbol for the element phosphorus is ________. a. Pt b. P c. Ca d. S e. K
b
What is the physical state in which matter has no specific shape but does have a specific volume? a. gas b. liquid c. salts d. ice e. solid
b
If matter is uniform throughout and cannot be separated into other substances by physical means, it is a. a homogeneous mixture b. a compound c. either an element or a compound d. an element e. a heterogeneous mixture
c
In the Rutherford nuclear-atom model, ________. a. mass is spread essentially uniformly throughout the atom b. the three principal subatomic particles (protons, neutrons, and electrons) all have essentially the same mass c. the heavy subatomic particles, protons and neutrons, reside in the nucleus d. the light subatomic particles, protons and neutrons, reside in the nucleus e. the three principal subatomic particles (protons, neutrons, and electrons) all have essentially the same mass and mass is spread essentially uniformly throughout the atom
c
Methane and ethane are both made up of carbon and hydrogen. In methane, there are 12.0 g of carbon for every 4.00 g of hydrogen, a ratio of 3:1 by mass. In ethane, there are 24.0 g of carbon for every 6.00 g of hydrogen, a ratio of 4:1 by mass. This is an illustration of the law of ________. a. constant composition b. conservation of mass c. multiple proportions d. octaves e. conservation of matter
c
The number 1.00430 has ________ significant figures. a. 2 b. 3 c. 6 d. 5 e. 4
c
The temperature of 25 °C is ________ in kelvins. a. 103 b. 166 c. 298 d. 248 e. 138
c
________ is the abbreviation for the prefix milli-. a. M b. k c. m d. d e. n
c
An object measuring 0.7500 kilograms will have a mass of ________ grams. a. 75.00 b. 0.0007500 c. 1333 d. 750.0 e. 7.500
d
In the symbol below, X = ________. (13/6)X a. Al b. N c. K d. C e. not enough information to determine
d
Which one of the following is a pure substance? a. soil b. a cup of coffee c. soda d. elemental oxygen e. apple
d
A combination of sand, salt, and water is an example of a ________. a. homogeneous mixture b. pure substance c. solid d. compound e. heterogeneous mixture
e
An atom of the most common isotope of gold, 197Au, has ________ protons, ________ neutrons, and ________ electrons. a. 118, 79, 39 b. 79, 118, 118 c. 197, 79, 118 d. 79, 118, 79 e. 79, 197, 197
e
The atomic number indicates ________. a. the number of different isotopes of an element b. the number of neutrons in a nucleus c. the total number of neutrons and protons in a nucleus d. the number of atoms in 1 g of an element e. the number of protons or electrons in a neutral atom
e
The density (in g/cm3) of a gold nugget that has a volume of 1.68 cm3 and a mass of 32.4 g is a. 0.0184 b. 0.0519 c. 54.4 d. 32.4 e. 19.3
e
Which one of the following is not an intensive property? a. boiling point b. density c. temperature d. melting point e. mass
e
