which of the following is a common characteristic of alkynes

ATI TEAS 7

TEAS 7 science quizlet

1. Which of the following is a common characteristic of alkynes?

A. They have a triple bond between carbon atoms.
B. They are saturated hydrocarbons.
C. They contain only single bonds.
D. They are aromatic compounds.

Correct answer: A

Rationale: The correct answer is A. Alkynes are hydrocarbons characterized by at least one triple bond between carbon atoms. This triple bond sets them apart from alkanes, which only have single bonds, and alkenes, which feature at least one double bond. The presence of a triple bond makes alkynes unsaturated hydrocarbons. Choice B is incorrect as alkynes are unsaturated hydrocarbons, not saturated. Choice C is incorrect because alkynes contain at least one triple bond, making them different from compounds with only single bonds. Choice D is incorrect because aromatic compounds have a distinct cyclic structure with resonance stabilization, a feature not shared by alkynes.

2. Which of the following hormones is responsible for regulating blood sugar levels?

A. Insulin
B. Adrenaline
C. Cortisol
D. Melatonin

Correct answer: A

Rationale: Insulin is the hormone responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells. Insulin helps lower blood sugar levels by promoting the storage of glucose in the liver, muscle, and fat cells. Adrenaline, cortisol, and melatonin do not directly regulate blood sugar levels. Adrenaline is involved in the fight-or-flight response, cortisol is a stress hormone that affects metabolism, immune response, and anti-inflammatory actions, while melatonin regulates sleep-wake cycles.

3. What happens to the frequency of a wave when its wavelength is doubled, assuming the speed remains constant?

A. Frequency remains the same.
B. Frequency is halved.
C. Frequency is doubled.
D. Frequency information is insufficient to determine.

Correct answer: B

Rationale: When the wavelength of a wave is doubled, and the speed of the wave remains constant, the frequency of the wave is halved. This relationship is governed by the equation speed = frequency x wavelength. Therefore, if the wavelength is doubled while the speed remains constant, the frequency must be halved to maintain a constant speed. Choice A is incorrect because frequency and wavelength are inversely proportional when speed is constant. Choice C is incorrect as doubling the wavelength does not result in a doubled frequency. Choice D is incorrect as the relationship between frequency, wavelength, and speed can be determined using the given information.

4. What happens to the density of a substance if its mass increases while its volume remains constant?

A. Density increases
B. Density decreases
C. Density remains constant
D. Density becomes zero

Correct answer: A

Rationale: When the mass of a substance increases while its volume remains constant, the density, which is calculated by dividing mass by volume, will increase. This is because with a higher mass and the volume staying the same, the ratio of mass to volume (density) will be greater, resulting in an overall increase in density. Choice B, 'Density decreases,' is incorrect because an increase in mass with constant volume leads to a higher density. Choice C, 'Density remains constant,' is incorrect as an increase in mass will cause the density to increase. Choice D, 'Density becomes zero,' is incorrect because even with an increase in mass, as long as volume remains constant, density will not reach zero; it will increase instead.

5. What is the main function of valence electrons in chemical bonding?

A. They are responsible for holding the nucleus together.
B. They are involved in forming bonds with other atoms.
C. They determine the element's physical properties.
D. They play no role in chemical reactions.

Correct answer: B

Rationale: Valence electrons are the electrons in the outermost energy level of an atom. These electrons are involved in forming bonds with other atoms, which is crucial for chemical bonding. By participating in bonding, valence electrons determine an atom's ability to form compounds and engage in chemical reactions. Therefore, the primary function of valence electrons is to facilitate the formation of bonds between atoms, making option B the correct answer. Choices A, C, and D are incorrect because valence electrons primarily influence chemical bonding by participating in the formation of bonds between atoms, rather than holding the nucleus together, determining physical properties, or having no role in chemical reactions.