Question

phase changes (graph: temperature, k (340, 320, 300, 280, 260, 240, 220, 200, 180, 160, 140) vs. time (0–20), labeled 1,2,3,4,5). part a: during the freezing phase on the graph, the temperature ... a stays the same b decreases c increases. part b: which area on the graph does the substance have particles that are close, but flow past each other a 2 b 3 c 5 d 4 e 1. part c: which number of the graph shows where the substance has no shape and no volume?

Explanation:

Part A

During a phase change like freezing (a phase transition from liquid to solid), the temperature remains constant because the energy is used for the phase change (latent heat) rather than changing temperature. So in the freezing phase (the flat part of the heating/cooling curve), temperature stays the same.

Particles that are close but flow past each other describe a liquid. In a heating/cooling curve, the liquid phase is typically the region between the melting (or freezing) and boiling (or condensation) phase changes. Looking at the graph:

• Region 1: Likely gas (particles far apart, moving freely)
• Region 2: Likely solid - liquid phase change (freezing/melting, flat line)
• Region 3: Likely liquid (particles close, flow past each other)
• Region 4: Likely liquid - solid phase change (freezing/melting, flat line)
• Region 5: Likely solid (particles close and fixed)

Wait, correction: Wait, actually, when cooling (since temperature is decreasing), region 1: gas (high temp, particles far), region 2: liquid - solid phase change (freezing, flat), region 3: liquid (cooling liquid, temp decreasing), region 4: liquid - solid phase change? No, maybe I mixed up. Wait, the phases:

• Gas: particles far, no shape/volume (region 1? No, region 1 is high temp, maybe gas cooling to liquid. Wait, the key is "particles close, but flow past each other" is liquid. So in the graph, region 3: when temperature is decreasing after the first phase change (freezing starts at region 2? No, maybe the graph is a cooling curve. Let's re - analyze:
• Region 1: Temperature decreasing, substance is gas (particles far)
• Region 2: Temperature constant, freezing (liquid to solid phase change)
• Region 3: Temperature decreasing, substance is liquid (particles close, flow past each other)
• Region 4: Temperature constant, another phase change (maybe solidification of another component? Or maybe condensation? No, wait, the y - axis is temperature in K. Wait, no, maybe the first flat line (region 2) is freezing (liquid to solid), so before that (region 1) is liquid? No, I think I made a mistake. Let's recall: In a cooling curve (temperature vs time), as we cool a gas, it condenses to liquid (temperature constant during condensation), then liquid cools (temperature decreases), then freezes to solid (temperature constant during freezing). Wait, the graph has two flat lines (region 2 and region 4). So:
• Region 1: Gas cooling (temperature decreasing, particles far)
• Region 2: Condensation (gas to liquid, temperature constant, particles become close, start to flow past each other? No, condensation is gas to liquid. Then region 3: liquid cooling (temperature decreasing, particles close, flow past each other)
• Region 4: Freezing (liquid to solid, temperature constant)
• Region 5: Solid cooling (temperature decreasing, particles close and fixed)

Wait, the question is "particles that are close, but flow past each other" which is liquid. So region 3? But the options have B as 3. Wait, but maybe I had the phases reversed. Alternatively, maybe region 3 is liquid. So the answer is B. 3? Wait, no, let's check the options again. The options for part B are A)2, B)3, C)5, D)4, E)1.

Wait, another approach: In a typical phase diagram (cooling curve):

• Gas: particles far apart, move freely (no shape/volume)
• Liquid: particles close, can flow past each other (definite volume, no definite shape)
• Solid: particles close, fixed in place (definite shape and volume)

Phase changes:

• Condensation: gas to liquid (temperature constant)
• Freezing: liquid to solid (temperature constant)

Looking at the graph:

• Region 1: Temperature is high, decreasing. So substance is gas (particles far)
• Region 2: Temperature constant (condensation? Gas to liquid)
• Region 3: Temperature decreasing, substance is liquid (particles close, flow past each other)
• Region 4: Temperature constant (freezing? Liqui…

A substance with no shape and no volume is a gas. In the graph, region 1 has the highest temperature, and at high temperatures (and depending on the phase), the substance is in the gas phase. So the number on the graph where the substance has no shape and no volume (gas) is region 1. But wait, let's check the graph. Region 1 is the first part where temperature is decreasing from 340 K. At high temperatures, the substance is gas (particles far apart, no definite shape or volume). So the answer should be the region corresponding to gas, which is region 1. But let's confirm:

• Gas: no shape, no volume (particles move freely, fill container)
• Liquid: definite volume, no definite shape (particles close, flow)
• Solid: definite shape and volume (particles close, fixed)

In the graph, region 1 is at the highest temperature, so it's gas. So the number is 1.

Answer:

A. stays the same

Part B