Question

what do these two changes have in common?
an iceberg melting slowly
snowflakes forming in a cloud
select all that apply.
both are changes of state.
both are chemical changes.
both are caused by cooling.
both are caused by heating.

Explanation:

1. Analyze "an iceberg melting slowly": This is a phase change from solid (ice) to liquid (water), a physical change (change of state), caused by heating (absorbing heat to melt).
2. Analyze "snowflakes forming in a cloud": This is a phase change from gas (water vapor) to solid (snowflakes, deposition), a physical change (change of state), caused by cooling (water vapor loses heat to form solid).
3. Evaluate options:

• "Both are changes of state": Correct, as both involve phase changes (melting: solid to liquid; snowflake formation: gas to solid).
• "Both are chemical changes": Incorrect, both are physical changes (no new substances with different chemical composition are formed).
• "Both are caused by cooling": Incorrect, iceberg melting is caused by heating, snowflake formation by cooling.
• "Both are caused by heating": Incorrect, snowflake formation is caused by cooling, iceberg melting by heating.

Answer:

A. Both are changes of state.