Download Exam Review 1: CHM 1411 Time: 0hr 55mins

Exam Review 1: CHM 1411
Time: 0hr 55mins
INSTRUCTIONS No cell phones are allowed. Your name and your ID number must be
written on your answer sheet.
Answer all Questions
SECTION A
1) Molecules can be described as
A) mixtures of two or more pure substances.
B) mixtures of two or more elements that has a specific ratio between components.
C) two or more atoms chemically joined together.
D) heterogeneous mixtures.
E) homogeneous mixtures.
Answer: C
2) Give the composition of water.
A) two hydrogen atoms and two oxygen atoms
B) one hydrogen atom and one oxygen atom
C) two hydrogen atoms and one oxygen atom
D) one hydrogen atom and two oxygen atoms
Answer: C
3) A substance that can't be chemically broken down into simpler substances is
A) a homogeneous mixture.
B) an element.
C) a heterogeneous mixture.
D) a compound.
E) an electron.
Answer: B
4) A physical change
A) occurs when iron rusts.
B) occurs when sugar is heated into caramel.
C) occurs when glucose is converted into energy within your cells.
D) occurs when water is evaporated.
E) occurs when propane is burned for heat.
Answer: D
5) A chemical change
A) occurs when methane gas is burned.
B) occurs when paper is shredded.
C) occurs when water is vaporized.
D) occurs when salt is dissolved in water.
E) occurs when powdered lemonade is stirred into water.
Answer: A
6) If the temperature is 128°F, what is the temperature in degrees celsius?
A) 262.4°C
B) 401°C
C) 53.3°C
D) -145°C
E) 328°C
Answer: C
7) If a solution has a temperature of 255 K, what is its temperature in degrees celsius?
A) 491°C
B) 528°C
C) 123.9°C
D) 355°C
E) -18°C
Answer: E
7) Determine the mass of an object that has a volume of 88.6 mL and a density of 9.77 g/mL.
A) 98.37 g
B) 0.110 g
C) 9.07 g
D) 78.8 g
E) 866 g
Answer: E
9) How many significant figures are there in the answer to the following problem?
(9.992 × 3.200) + 0.610 = ?
A) one
B) two
C) three
D) four
Answer: C
10.The statement, "In a chemical reaction, matter is neither created nor destroyed" is called
A) the Law of Conservation of Mass.
B) Dalton's Atomic Theory.
C) the Scientific Method.
D) the Law of Multiple Proportions.
E) the Law of Definite Proportions.
Answer: A
11) Precision refers to ________.
A) how close a measured number is to other measured numbers
B) how close a measured number is to the true value
C) how close a measured number is to the calculated value
D) how close a measured number is to zero
E) how close a measured number is to infinity
12) What does "X" represent in the following symbol?
X
A) silicon
B) sulfur
C) zinc
D) ruthenium
E) nickel
Answer: A
13) Identify the description of an atom.
A) neutrons and electrons in nucleus; protons in orbitals
B) neutrons in nucleus; protons and electrons in orbitals
C) protons and neutrons in nucleus; electrons in orbitals
D) protons and electrons in nucleus; neutrons in orbitals
E) electrons in nucleus; protons and neutrons in orbitals
Answer: C
14) The mass number is equal to
A) the sum of the number of the electrons and protons.
B) the sum of the number of the neutrons and electrons.
C) the sum of the number of protons, neutrons, and electrons.
D) the sum of the number of protons and neutrons.
Answer: D
15) An atom of the most common isotope of gold,
Au, has ________ protons, ________ neutrons, and
________ electrons.
A) 197, 79, 118
B) 118, 79, 39
C) 79, 197, 197
D) 79, 118, 118
E) 79, 118, 79
Answer: E
16) Which one of the following is the formula of hydrochloric acid?
A) HClO3
B) HClO4
C) HClO
D) HCl
E) HClO2
17) Which one of the following compounds is chromium(III) oxide?
A) Cr2O3
B) CrO3
C) Cr3O2
D) Cr3O
E) Cr2O4
Answer: A
18) The correct name for HNO2 is ________.
A) nitrous acid
B) nitric acid
C) hydrogen nitrate
D) hyponitrous acid
E) pernitric acid
Answer: A
19) The correct name for MgF2 is ________.
A) monomagnesium difluoride
B) magnesium difluoride
C) manganese difluoride
D) manganese bifluoride
E) magnesium fluoride
Answer: E
20) The empirical formula of a compound with molecules containing 12 carbon atoms, 14 hydrogen
atoms, and 6 oxygen atoms is ________.
A) C12H14O6
B) CHO
C) CH2O
D) C6H7O3
E) C2H4O
Answer: D
21) Predict the empirical formula of the ionic compound that forms from aluminum and oxygen.
A) AlO
B) Al3O2
C) Al2O3
D) AlO2
E) Al2O
Answer: C
22) When the following equation is balanced, the coefficients are ________.
C8H18 + O2 → CO2 + H2O
A) 2, 3, 4, 4
B) 1, 4, 8, 9
C) 2, 12, 8, 9
D) 4, 4, 32, 36
E) 2, 25, 16, 18
Answer: E
23) The formula weight of potassium dichromate (K2Cr2O7 ) is ________ amu.
A) 107.09
B) 255.08
C) 242.18
D) 294.18
E) 333.08
Answer: D
24) When the following equation is balanced, the coefficient of Al is ________.
Al (s) + H2O (l) → Al(OH)3 (s) + H2 (g)
A) 1
B) 2
C) 3
D) 5
E) 4
Answer: B
25) How many sulfur dioxide molecules are there in 1.80 mol of sulfur dioxide?
A) 1.08 × 1023
B) 6.02 × 1024
C) 1.80 × 1024
D) 1.08 × 1024
E) 6.02 × 1023
Answer: D
26) The total number of atoms in 0.111 mol of Fe(CO) 3(PH3)2 is ________.
A) 15.0
B) 1.00 × 1024
C) 4.46 × 1021
D) 1.67
E) 2.76 × 10-24
Answer: B
27) A compound that is composed of carbon, hydrogen, and oxygen contains 70.6% C, 5.9% H, and 23.5%
O by mass. The molecular weight of the compound is 136 amu. What is the molecular formula?
A) C8H8O2
B) C8H4O
C) C4H4O
D) C9H12O
E) C5H6O2
Answer: A
28) The quantity 1.0 mg/cm2 is the same as 1.0 × ________ kg/m2.
A) 10-4
B) 102
C) 10-6
D) 10-2
E) 104
Answer: D
29) Convert 2 μm to meters.
A) 2 × 10-9 m
B) 2 × 10-6 m
C) 2 × 10-3 m
D) 2 × 106 m
Answer: B
30) The mass of a single zinc atom is 1.086 × 10-22 g. This is the same mass as
A) 1.086 × 10-16 mg.
B) 1.086 × 10-25 kg.
C) 1.086 × 10-28 μg.
D) 1.086 × 10-31 ng.
Answer: B
31) A piece of metal ore weighs 8.25 g. When a student places it into a graduated cylinder
containing water, the liquid level rises from 21.25 mL to 26.47 mL. What is the density of the
ore?
A) 0.312 g/mL
B) 0.633 g/mL
C) 1.58 g/mL
D) 3.21 g/mL
Answer: C
32) The element chlorine is in a group known as the _______.
A) transition metals
D) alkaline earth metals
B) noble gases
E) halogens
33) The element calcium is in a group known as the _______.
A) transition metals
B) alkali metals
D) noble gases
E) alkaline earth metals
C) alkali metals
C) halogens
34) A small amount of salt dissolved in water is an example of a ________.
A) homogeneous mixture
B) heterogeneous mixture
C) compound
D) pure substance
E) solid
35) The outside air temperature is 40°F, what is the temperature in Kelvin?
A) 313 K
B) 377 K
C) 281 K
D) 277 K
Answer: D
SECTION B. SHOW YOUR CALCULATIONS
1. The element X has three naturally occurring isotopes. The masses (amu) and %
abundances of the isotopes are given in the table below. The average atomic mass of the
element is ________ amu.
2. How many grams of N2(g) can be made from 9.05 g of NH3 reacting with 45.2 g of CuO?
2 NH3(g) + 3 CuO(s) → N2(g) + 3 Cu(s) + 3 H2O(l)
If 4.61 g of N2 are made, what is the percent yield?
3. A compound was found to contain 90.6% lead (Pb) and 9.4% oxygen. The empirical
formula for this compound is ________.
4. What is the mass % of carbon in dimethylsulfoxide (C2H6SO) rounded to three
significant figures?
5.
How many molecules of CH4 are in 48.2 g of this compound?