Question: Diiodine pentoxide is used as an oxidizing agent that converts carbon monoxide to carbon dioxide. What is its chemical formula?
Answer Choices:
A. (IO₅)₂
B. I₂O₅
C. IO₅
D. I₅O₂
E. 2IO₅
Answer: B. I₂O₅
Question: What is the mass of 7.80 × 10¹⁸ carbon atoms? (Nₐ = 6.022 × 10²³ mol⁻¹)
Answer Choices:
A. 1.56 × 10⁻⁴ g
B. 12.01 g
C. 6.43 × 10³ g
D. 1.30 × 10⁻⁵ g
E. 7.80 × 10¹⁸ g
Answer: A. 1.56 × 10⁻⁴ g
Question: An oxide of gadolinium contains 86.76 mass % Gd. What is its empirical formula?
Answer Choices:
A. Gd₃O₂
B. Gd₃O₄
C. Gd₂O₃
D. GdO
E. Gd₁₃O₂
Answer: C. Gd₂O₃
Question: Construct two squares of different size and explain how to construct a new square whose area is the sum of the areas of the two squares.
Answer Choices:
A. Construct a square with side length that is the sum of the lengths of the sides of the two squares. The constructed square will have area equal to the sum of the areas of the two squares.
B. Construct a square with side length that is the sum of the squares of the lengths of the sides of the two squares. The constructed square will have area equal to the sum of the areas of the two squares.
C. Construct a right triangle whose legs have length equal to lengths of the sides of the two squares. The square constructed on the hypotenuse will have area equal to the sum of the areas of the two squares.
D. Construct a right triangle whose legs have length equal to the squares of the lengths of the sides of the two squares. The square constructed on the hypotenuse will have area equal to the sum of the areas of the two squares.
Answer: C. Construct a right triangle whose legs have length equal to lengths of the sides of the two squares. The square constructed on the hypotenuse will have area equal to the sum of the areas of the two squares.
Question: Researchers wanted to determine if there was an association between the level of stress of an individual and their risk of heart disease. The researchers studied 1714 people over the course of 13 years. During this time, they interviewed individuals about their daily lives and assessed emotions. They also determined which individuals experienced heart disease during the 13-year period.
(a) What type of observational study was this? (b) What is the response variable? What is the explanatory variable? (c) What does it mean that genetics could be causing both emotions and heart disease?
Answer Choices:
(c)
A. It is not important to adjust for explanatory variables.
B. The researchers may be concerned with confounding when the effects of two or more explanatory variables are not separated or when an unconsidered variable affects the response.
C. The researchers thought genetics had greater influence than level of stress.
Answer: A. Cohort study; B. Response variable: development of heart disease; C. B. Confounding variable concern
Question: Are any two cubes similar? Why or why not?
Answer Choices:
A. Any two cubes are not similar because all the faces are not squares and the dihedral angles between two adjacent faces measure 90°.
B. Any two cubes are similar because all the faces are squares and the dihedral angles between two adjacent faces measure 90°.
C. Any two cubes are similar because all the faces are squares and the dihedral angles between two adjacent faces measure 45°.
D. Any two cubes are not similar because all the faces are squares and the dihedral angles between two adjacent faces measure 90°.
Answer: B. Any two cubes are similar because all the faces are squares and the dihedral angles between two adjacent faces measure 90°.
Question: Calculate the mass in grams of 8.35 × 10²² molecules of CBr₄.
Answer Choices:
A. 12.7 g
B. 0.139 g
C. 0.0217 g
D. 46.0 g
E. 7.21 g
Answer: B. 0.139 g
Question: A polling organization conducts a study to estimate the percentage of households that have Internet access. It mails a questionnaire to 1153 randomly selected households across the country and asks the head of each household if he or she has Internet access. Of the 1153 households selected, 16 responded.
(a) Which of these best describes the bias in the survey? (b) How can the bias be remedied?
Answer Choices:
(a)
Response bias
Sampling bias
Undercoverage bias
Nonresponse bias
(b)
A. The polling organization should mail the questionnaire to each person in the households.
B. The polling organization should mail the questionnaire to a greater number of households.
C. The polling organization should only select households in a single state.
D. The polling organization should try contacting households that do not respond by phone or face-to-face.
Answer: A. Nonresponse bias; B. D. The polling organization should try contacting households that do not respond by phone or face-to-face.
Question: A drug company wanted to test a new indigestion medication. The researchers found 600 adults aged 25–35 and randomly assigned them to one of two groups. The first group received the new drug, while the second received a placebo. After one month of treatment, the percentage of each group whose indigestion symptoms decreased was recorded and compared. What type of experimental design is this?
Answer Choices:
Single-blind design
Randomized block design
Completely randomized design
Matched pairs design
Answer: Completely randomized design
Question: Which of the following is a nonmetal?
Answer Choices:
A. Mercury, Hg, Z = 80
B. Sodium, Na, Z = 11
C. Bismuth, Bi, Z = 83
D. Bromine, Br, Z = 35
E. Lithium, Li, Z = 3
Answer: D. Bromine, Br, Z = 35