Molecules in Motion
Before melting, how do solid water molecules move?
(Answer: They vibrate in place.)
On a cooling curve, molecules get closer together. Is kinetic energy increasing or decreasing?
(Answer: Decreasing.)
Water left outside as ice melts to liquid — how did molecules change
From vibrating in place to moving around each other.)
What happens to molecular attraction during condensation?
Answer: Attraction increases as molecules move closer together.)
What does “CER” stand for?
(Claim, Evidence, Reasoning.)
What happens to water molecules when temperature increases from 18°C to 25°C?
Answer: They move faster.)
: On a heating curve, when temperature is constant but heat is still being added, what type of energy increases?
(Answer: Potential energy.)
Which phase change is happening when dew forms?
(Answer: Condensation.)
Why does gas fill its container? Attraction & how molecules move
Answer: Low attraction, molecules spread freely.)
Which part of CER answers why evidence supports the claim?
Reasoning
In chocolate making, going from liquid to solid — how do the molecules change movement?
(Answer: From moving around each other to moving in place.)
Which sections of a heating curve represent phase changes?
(Answer: Flat sections – B and D.)
A puddle disappears in the sun. Which phase change occurred?
(Answer: Evaporation.)
What makes one liquid change phase while another doesn’t under the same energy input?
(Answer: Differences in molecular attraction strength.)
Claim: “Condensation is a cooling process.” Give 1 piece of evidence.
(Answer: Particles slow down and get closer together.)
In evaporation, how do molecules change?
(Answer: They move faster and spread apart.)
In the jar of sweet liquid ( Weak Attraction) vs sour food liquid (Strong Attraction), which changed and why? What did they over come
Answer: Sweet food, because molecules overcame attraction and spread apart.)
Mineral A vs Mineral B → Why did only Mineral A change phase?
(Answer: Molecules gained enough energy to overcome attraction; Mineral B’s attraction was too strong.)
Claim: “Mineral A changed but Mineral B didn’t.” Explain why.
(Answer: Mineral A molecules overcame attraction, Mineral B’s didn’t.)
Why do some substances change phase while others don’t when the same energy is added?
(Answer: Differences in molecular attraction.)
Full CER: Explain why ice melts in the sun.
(Claim: Ice melts because heat was added. Evidence: Ice changed from solid to liquid. Reasoning: Heat made molecules move faster and overcome attraction.)