Question

phase changes (graph: temperature vs energy added, labels 1,2,3,4,5) part a the graph above is a select one curve part b how does the temperature change at area 3? a stays the same b increases c decreases part c what state would the substance be in at 100°c? a solid b boiling c freezing d melting e condensation f gas g liquid

Explanation:

Part A

The graph shows temperature vs. energy added for phase changes, typical of a heating curve (shows temperature change and phase transitions as energy is added). So it's a heating curve.

In area 3 of a heating curve, the substance is in a single phase (liquid, likely) and as energy is added, temperature increases (the sloped line indicates temperature rise with energy input, unlike flat lines which are phase changes with constant temp).

At 100°C (assuming water, but generally, the flat part at 100°C in a heating curve is boiling/condensation, but when temperature is at 100°C during heating, the substance can be boiling (liquid and gas co - exist) or liquid (before boiling starts? Wait, no—area 2 is flat at 100, which is boiling (phase change between liquid and gas). But at 100°C, the substance can be in liquid (before boiling completes), boiling (liquid and gas), or gas (after boiling). But looking at the options, "Boiling" (B) is when phase change occurs at 100, and also liquid (G) and gas (F) can be present. Wait, the flat line (area 2) is boiling (phase change: liquid to gas, constant temp). So at 100°C, the substance is boiling (B), and also can be liquid (G) or gas (F). But the most appropriate: when at 100°C during the phase change (area 2), it's boiling (liquid and gas), but also, if we consider the state, at 100°C, the liquid is boiling (so B is correct, and also G and F, but the options: B is Boiling, G is Liquid, F is Gas. Wait, the flat part is the boiling point, so during that time, the substance is undergoing boiling (phase change from liquid to gas), so the state change process is boiling, and the substance can be liquid (before boiling finishes), boiling (liquid + gas), or gas (after). But the question is "what state would the substance be in at 100°C?". At 100°C, if it's in the phase change (area 2), it's boiling (B), and also liquid (G) and gas (F) are present. But among the options, B (Boiling) is the process, but states: liquid (G) and gas (F) are states. Wait, maybe the graph: area 2 is flat at 100, which is boiling (liquid to gas). So at 100°C, the substance can be liquid (before boiling starts, but area 3 is liquid heating to 100, area 2 is boiling). Wait, no—area 5: solid heating, area 4: melting (solid to liquid, constant temp), area 3: liquid heating, area 2: boiling (liquid to gas, constant temp), area 1: gas heating. So at 100°C (area 2), the substance is boiling (phase change), so the state change is boiling, but the states present are liquid and gas. But the options: B is Boiling (process), G is Liquid, F is Gas. Wait, maybe the question is about the state during the boiling process. At 100°C, the substance is boiling (so B is correct), and also liquid (G) and gas (F) are present. But maybe the intended answer is B (Boiling) or G (Liquid) or F (Gas). Wait, when you heat water to 100°C, it's liquid until it starts boiling, then during boiling (at 100°C), it's both liquid and gas (boiling). So among the options, B (Boiling) is the process, G (Liquid) is a state present, F (Gas) is a state present. But the options: let's re - check. The options for Part C: A. Solid, B. Boiling, C. Freezing, D. Melting, E. Condensation, F. Gas, G. Liquid. So "Boiling" is a process, but the question is "what state would the substance be in at 100°C?". So states are solid, liquid, gas. At 100°C, during boiling, the substance is in liquid (G) and gas (F) states, and the process is boiling (B). But maybe the graph's area 2 is the boiling phase (liquid to gas), so at 100°C, the substance is boiling (B), and also liquid (G) and gas (F) are present. But perhaps the intended answer is B (Boiling) or G (Liquid) or F (Gas). Wait, maybe the substance is water, so at 100°C, it can be liquid (before boiling), boiling (liquid and gas), or gas (after boiling). But in the graph, area 2 is flat, so it's the boiling phase. So the state change process is boiling (B), and the states present are liquid (G) and gas (F). But the question is "what state would the substance be in at…

Answer:

Heating

Part B