In the graph, a sample of water is heated from 40 degrees Celsius to 100 degrees Celsius. Which statement correctly describes the curve?

Question

Responses
A QR- liquid only
RS- phase change liquid-gas
ST- gas onlyQR- liquid only RS- phase change liquid-gas ST- gas only
B QR- liquid only
RS- phase change liquid-solid
ST- solid onlyQR- liquid only RS- phase change liquid-solid ST- solid only
C QR- solid only
RS- phase change solid-liquid
ST- liquid only

QR- solid only RS- phase change solid-liquid ST- liquid only
D QR- phase change solid-liquid
RS- liquid only
ST- phase change liquid-gas

Answer 1

To analyze the descriptions based on the heating of water from 40 degrees Celsius to 100 degrees Celsius, we can consider the following key points:

1. QR Segment: Starting at 40 degrees, water is in the liquid state as it is below its boiling point.
2. RS Segment: This segment represents the phase change from liquid to gas, which occurs at 100 degrees Celsius during boiling.
3. ST Segment: After reaching 100 degrees Celsius, water is in the gas state (steam) as it is heated further.

Given this heating process, the correct description of the segments is:

• QR: Liquid only (below boiling point, water is in liquid state)
• RS: Phase change liquid-gas (boiling point at 100 degrees Celsius)
• ST: Gas only (after boiling, water is in gas state)

Therefore, the correct choice from the given options is:

A: QR- liquid only, RS- phase change liquid-gas, ST- gas only.