Question

what do these two changes have in common?
dew appearing on grass in the morning
butter melting on a hot day
select all that apply.
both are only physical changes.
both are chemical changes.
both are caused by heating.
both are caused by cooling.
submit
work it out
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Explanation:

1. Analyze dew appearance: Dew forms when water vapor in the air condenses (gas to liquid) on grass. This is a physical change (no new substance, just state change) and is caused by cooling (night/morning cooling of air).
2. Analyze butter melting: Butter melts from solid to liquid due to heat (hot day). This is a physical change (no new substance, just state change) and is caused by heating.
3. Evaluate options:

• "Both are only physical changes": Correct, as both involve state changes (condensation, melting) with no new chemical substance.
• "Both are chemical changes": Incorrect, no chemical reactions (no new substances formed).
• "Both are caused by heating": Incorrect, dew is from cooling, butter from heating.
• "Both are caused by cooling": Incorrect, butter is from heating, dew from cooling.

Answer:

A. Both are only physical changes