sublimation is the change in matter from solid to gas or gas to solid without passing through a liquid phase outside of the laboratory which solid pro

HESI A2

HESI Exams Quizlet Physics

1. Sublimation is the change in matter from solid to gas or gas to solid without passing through a liquid phase. Outside of the laboratory, which solid provides the best example of this?

A. Iron
B. Silver
C. Salt crystal
D. Dry ice

Correct answer: D

Rationale: Dry ice (solid carbon dioxide) provides the best example of sublimation outside of the laboratory. When dry ice is exposed to normal atmospheric conditions, it changes directly from a solid to a gas without passing through a liquid phase. This process is commonly observed in everyday situations such as creating 'smoke' or 'fog' effects. Choices A, B, and C (Iron, Silver, and Salt crystal) do not undergo sublimation. Iron and Silver melt and then vaporize, while Salt crystal dissolves in water, and the resulting solution evaporates, which involves a liquid phase.

2. A 3-volt flashlight uses a bulb with 60-ohm resistance. What current flows through the flashlight?

A. o.05 amp
B. o.5 amp
C. 1.8 amp
D. 18 amp

Correct answer: A

Rationale: : Using Ohm's Law, I = V / R: I = 3 / 60 = 0.05 amp. So, the correct current is 0.05 amp.

3. Which property of a substance does not change with a change in temperature?

A. Mass
B. Volume
C. Phase
D. Solubility

Correct answer: A

Rationale: Mass is an intrinsic property of a substance that remains constant regardless of temperature changes. It is a measure of the amount of matter in an object, and this quantity does not vary with temperature or the environment in which the substance is located. The conservation of mass in chemistry dictates that mass is neither created nor destroyed, making it independent of temperature variations.\nVolume, on the other hand, changes with temperature due to thermal expansion or contraction. Phase can change with temperature, leading to transitions between solid, liquid, and gas states. Solubility is affected by temperature changes as it influences the ability of a substance to dissolve in a solvent.

4. If a 5-kg ball is moving at 5 m/s, what is its momentum?

A. 10 kg⋅m/s
B. 16.2 km/h
C. 24.75 kg⋅m/s
D. 25 kg⋅m/s

Correct answer: D

Rationale: The momentum of an object is calculated by multiplying its mass by its velocity. In this case, the mass of the ball is 5 kg and its velocity is 5 m/s. Therefore, the momentum of the ball is 5 kg × 5 m/s = 25 kg⋅m/s. Choice A (10 kg⋅m/s) is incorrect as it does not account for both mass and velocity. Choice B (16.2 km/h) is incorrect as it provides a speed in a different unit without considering mass. Choice C (24.75 kg⋅m/s) is incorrect as it does not correctly calculate the momentum based on the given mass and velocity.

5. An object moves 100 m in 10 s. What is the velocity of the object over this time?

A. 10 m/s
B. 90 m/s
C. 110 m/s
D. 1,000 m/s

Correct answer: A

Rationale: Velocity is calculated as the displacement divided by the time taken to cover that displacement. In this case, the object moves 100 meters in 10 seconds. Therefore, the velocity is 100 m / 10 s = 10 m/s. Choice B, 90 m/s, is incorrect as it doesn't match the calculated velocity. Choice C, 110 m/s, is incorrect as it is higher than the calculated velocity. Choice D, 1,000 m/s, is incorrect as it is significantly higher than the calculated velocity.