Question

a.) at what temperature did freezing occur?
°c
b.) how long was the process of condensation?
min
c.) when was the object completely solid?
from min to min.
d.) over what temperature range was the object completely liquid? state the range from smallest to largest.
from °c to °c.

Explanation:

Part a)

Step1: Identify freezing plateau

Freezing occurs at the temperature where the graph has a horizontal (constant temperature) segment (freezing plateau). From the graph, the horizontal segment for freezing (or solidification) is at 200°C? Wait, no, wait—wait, maybe I misread. Wait, the graph: let's check the horizontal parts. Wait, the first horizontal part is at 350°C (from 15 to 40 min maybe? Wait, no, the x-axis: 0-10, then 10-20? Wait, the graph: at x=10 to x=40, temperature is 350? No, wait the y-axis is temperature (Celsius), x-axis time (min). Wait, the first horizontal segment: from ~15 to 40 min, temperature 350? No, then next horizontal at 200? Wait, no, freezing (solidification) is when liquid becomes solid, so the temperature where the phase change (solid-liquid) occurs, so the horizontal line for that. Wait, looking at the graph: the horizontal segment at 200°C, from x=65 to x=75? No, wait x=60 to x=80? Wait, no, let's re-express. Wait, the graph: starts at 450°C (t=0), decreases to 350 at t=15, stays constant until t=40, then decreases to 200 at t=65, stays constant until t=75, then decreases to 100 at t=100. Wait, no, maybe the horizontal segments: first plateau (condensation? No, condensation is gas to liquid, but here maybe it's cooling a substance: first, liquid cooling, then phase change (freezing) at constant temp, then solid cooling. Wait, no, maybe the first plateau is condensation (gas to liquid), second is freezing (liquid to solid). Wait, no, the problem says "freezing" (liquid to solid), so the temperature where liquid becomes solid is the freezing point, which is the horizontal segment (constant temperature) during solidification. So looking at the graph, the horizontal segment at 200°C (from t=65 to t=75? Wait, no, the x-axis: t=60 to t=80? Wait, the graph's horizontal part: at t=65 to t=75, temperature 200? Wait, no, let's check the coordinates. Wait, the y-axis: 100,150,200,250,300,350,400,450. The x-axis: 0,10,20,30,40,50,60,70,80,90,100. So at t=10 to t=40, temperature is 350 (horizontal line). Then t=40 to t=65, temperature decreases from 350 to 200. Then t=65 to t=75, temperature is 200 (horizontal line). Then t=75 to t=100, temperature decreases to 100. Wait, so freezing (liquid to solid) is the phase change from liquid to solid, so the temperature at which that happens is the freezing point, which is the horizontal segment (constant temperature) during solidification. So that's 200°C? Wait, no, maybe the first plateau is condensation (gas to liquid) at 350°C, then liquid cooling, then freezing at 200°C. So for part a, freezing occurs at 200°C? Wait, but maybe I made a mistake. Wait, let's check the graph again. The horizontal line at 200°C (from t=65 to t=75) is the freezing (solidification) plateau. So freezing temperature is 200°C.

Step2: Confirm the freezing temperature

The freezing (solidification) of the liquid occurs at the temperature where the graph has a horizontal segment (constant temperature) during the phase change from liquid to solid. From the graph, this horizontal segment is at 200°C.

Step1: Identify condensation plateau

Condensation (gas to liquid) occurs at the temperature where the graph has a horizontal segment (constant temperature) during the phase change from gas to liquid. From the graph, the first horizontal segment is from t=15 min to t=40 min (approx, but looking at the x-axis: from t=10 to t=40, temperature is 350°C). Wait, the time duration is end time - start time. So start time of condensation plateau: t=15 min (or 10 min), end time t=40 min. So duration is 40 - 15 = 25 min? Wait, no, looking at the graph: the horizontal segment (condensation) is from t=10 min to t=40 min? Wait, the x-axis: at t=10, temperature is 350, and it stays 350 until t=40. So duration is 40 - 10 = 30 min? Wait, 40 - 10 = 30. Wait, t=10 to t=40: 30 minutes.

Step2: Calculate duration

Duration = end time - start time = 40 - 10 = 30 minutes.

Step1: Identify solid phase time

The object is completely solid after the freezing (solidification) phase change is complete. The freezing (solidification) plateau is from t=65 min to t=75 min? Wait, no, after the freezing plateau (where liquid becomes solid), the temperature continues to decrease (solid cooling). Wait, no: the freezing (solidification) occurs at the horizontal segment (t=60 to t=80? Wait, earlier analysis: after t=75 min, the temperature decreases, so the object is completely solid from the end of the freezing plateau until the end (t=100 min). Wait, the freezing plateau is from t=65 min to t=75 min (temperature 200°C), so after t=75 min, the object is completely solid. Wait, no: when the phase change (liquid to solid) is complete, the substance is solid. So the solid phase starts when the freezing (solidification) is complete, i.e., after the horizontal segment. So the freezing plateau is from t=65 to t=75 (liquid to solid), so after t=75, it's completely solid. Wait, but the problem says "from [ ] min to [ ] min". Wait, maybe the solid phase is from the end of the freezing plateau to the end. Wait, the graph: after t=75, temperature decreases (solid cooling), so from t=75 min to t=100 min, the object is completely solid. Wait, but the check mark is on the second box, maybe the correct end is 100. Wait, let's see: the freezing (solidification) is from t=65 to t=75 (liquid to solid), so after t=75, it's solid. So from 75 min to 100 min.

Step2: Determine start and end

Start time: 75 min (when solidification is complete), end time: 100 min (end of graph).

Answer:

200

Part b)