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Which element is a good conductor of electricity but is not a metal?
- A. Copper
- B. Silver
- C. Graphite
- D. Gold
Correct Answer: C
Rationale: The correct answer is graphite. Graphite is a non-metal that is a good conductor of electricity due to its unique electronic structure. While metals are typically known for their conductivity, graphite is an exception to this rule. Copper (choice A), silver (choice B), and gold (choice D) are all metals and are known for their excellent conductivity. Therefore, they do not fit the criteria of the question, which specifically asks for an element that is a good conductor of electricity but is not a metal.
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A car is accelerating down a hill. Which of the following forces is NOT acting on the car?
- A. Gravitational force
- B. Normal force from the road
- C. Air resistance
- D. The car's engine force
Correct Answer: B
Rationale: When a car is accelerating down a hill, the normal force from the road is not acting on the car. The normal force is the force exerted by a surface to support the weight of an object resting on it. As the car moves downhill, the normal force decreases since the road is no longer pushing back against the car's weight due to the downhill motion. Gravitational force pulls the car downhill, air resistance opposes the car's motion, and the car's engine force propels it forward. Therefore, the correct answer is B, as the normal force from the road is not acting on the car while it accelerates downhill.
What functional group is present in ethers?
- A. Hydroxyl
- B. Carbonyl
- C. Ether
- D. Amine
Correct Answer: C
Rationale: The functional group present in ethers is -O-, representing an oxygen atom bonded to two alkyl or aryl groups. Therefore, choice C, 'Ether,' is the correct answer. Choices A, B, and D refer to different functional groups: hydroxyl (-OH), carbonyl (C=O), and amine (NH2), respectively, which are not present in ethers. Ethers are characterized by the oxygen atom bonded to two carbon groups, distinguishing them from the other functional groups mentioned in the choices.
What does the term 'dilution' refer to in a solution?
- A. Adding more solvent to decrease concentration
- B. Adding more solute to increase concentration
- C. Reducing the temperature to increase solubility
- D. Increasing pressure to increase solubility
Correct Answer: A
Rationale: The term 'dilution' in a solution refers to adding more solvent to decrease the concentration of the solution. Dilution involves reducing the concentration of the solute in the solution by increasing the amount of solvent. Choice B is incorrect because adding more solute would increase the concentration, not decrease it. Choices C and D are also incorrect as they relate to factors affecting solubility, not dilution specifically. Therefore, choice A is the correct answer as it accurately defines the process of dilution in a solution.
Which of the following is NOT a common route of transmission for a sexually transmitted infection (STI)?
- A. Unprotected sexual contact
- B. Sharing contaminated needles
- C. Deep kissing
- D. Mother to child during childbirth
Correct Answer: C
Rationale: A) Unprotected sexual contact is a common route of transmission for sexually transmitted infections (STIs) as many STIs are spread through genital, anal, or oral sex without the use of barrier protection such as condoms. B) Sharing contaminated needles can also transmit STIs such as HIV and hepatitis B and C, especially among individuals who inject drugs. C) Deep kissing, while it can transmit certain infections like herpes simplex virus (HSV-1) or cytomegalovirus (CMV), is not a common route of transmission for most STIs. Although some STIs can be transmitted through saliva, deep kissing is not a primary mode of transmission for most STIs. D) Mother to child transmission during childbirth can occur with certain STIs such as HIV, syphilis, and herpes, where the infection can be passed from the mother to the baby during delivery. Therefore, deep kissing (option C) is the correct answer as it is not a typical route of transmission for most STIs.
Antibiotic resistance in bacteria is an example of:
- A. Convergent evolution
- B. Divergent evolution
- C. Microevolution
- D. Macroevolution
Correct Answer: C
Rationale: Antibiotic resistance in bacteria is a classic example of microevolution (option C). Microevolution refers to changes in allele frequencies within a population over a relatively short period of time. In the case of antibiotic resistance, bacteria evolve resistance to antibiotics through the natural selection of pre-existing resistant strains. This process does not involve the formation of new species or higher taxonomic groups, which are associated with macroevolution (option D). Convergent evolution (option A) involves different species independently evolving similar traits in response to similar environmental pressures, which is not the case with antibiotic resistance in bacteria. Divergent evolution (option B) refers to related species becoming more dissimilar over time, which also does not apply to the scenario of antibiotic resistance in bacteria.