Question

phase changes
heating curve of substance x (graph with temperature (°c) vs time (minutes))
part a
which area of the graph shows where the particles only vibrate in place?
a iii
b iv
c v
d ii
e i
part b
after area iv on the graph, the particles of the substance move
select one and select one
part c
while undergoing the temperature changes shown in the graph, the
substance select one energy(heat).
part d
the freezing point is
the boiling point is

Explanation:

Part A

In a heating curve, the region where particles only vibrate in place is the solid phase (lowest temperature, before melting). Area I is the solid phase (temperature increasing while solid, particles vibrate). Wait, no—wait, phase changes: Area I is solid (heating solid, temp rises, particles vibrate). Wait, no, let's recall: Heating curve regions: I (solid, temp rising), II (melting, phase change, temp constant), III (liquid, temp rising), IV (boiling, phase change, temp constant), V (gas, temp rising). In solid (Area I), particles vibrate in place. Wait, but the options: E is I. Wait, let's check again. Wait, maybe I mixed up. Wait, when a substance is solid, particles vibrate in fixed positions. So the area where it's solid (before melting) is Area I (since I is from -20 to ~5°C, then II is melting (temp constant at ~5°C), then III is liquid (temp rising), IV is boiling (temp constant at ~50°C), V is gas (temp rising). So in solid (Area I), particles vibrate in place. So the correct option is E. I.

After Area IV (which is the boiling phase change, so after IV is the gas phase). In gas, particles move faster (higher kinetic energy) and are more freely (more space between them, move in random directions, more rapidly). So the first dropdown: "faster" (since gas has higher KE than liquid) and the second dropdown: "more freely" (or "farther apart" but movement: faster and more freely).

During temperature changes (the sloped regions: I, III, V) and phase changes (flat regions: II, IV), the substance absorbs energy (heat). Because heating curve: adding heat (energy) to increase temp or change phase. So the substance "absorbs" energy (heat).

Answer:

E. I

Part B