Question 1
A solid piece of chocolate is left in the sun and slowly turns into a runny liquid. Which term best describes this change?No clue? Show me the answer
Correct answerCorrect!
IncorrectStep-by-step walkthrough
Choose a solution method
Method #1Direct ApproachStep 1: Identify the change occurring
The chocolate starts as a solid and becomes a liquid when heated by the sun.
Step 2: Match the change to the correct term
The change from solid → liquid when a substance is heated is called melting. This occurs at the substance's melting point.
Step 3: Select the correct answer
The correct answer is Melting, as the chocolate is changing from solid to liquid due to heat energy.
Method #2Process of EliminationStep 1: Identify what is being asked
We need to name the process by which a solid becomes a liquid when heated.
Step 2: Eliminate 'Evaporation'
Evaporation is the change from liquid to gas below the boiling point. The chocolate is going from solid to liquid, not liquid to gas, so this is incorrect.
Step 3: Eliminate 'Condensation'
Condensation is the change from gas to liquid. The chocolate is not a gas, so this does not apply.
Step 4: Eliminate 'Sublimation'
Sublimation is the change from solid directly to gas, skipping the liquid phase. The chocolate becomes a liquid, not a gas, so this is wrong.
Step 5: Select the correct answer
The only remaining option is Melting, which correctly describes a solid turning into a liquid when heated.
Question 2
Which of the following best describes the arrangement and movement of particles in a liquid?No clue? Show me the answer
Correct answerCorrect!IncorrectStep-by-step walkthrough
Choose a solution method
Method #1Direct ApproachStep 1: Recall the properties of a liquid
A liquid has a fixed volume but takes the shape of its container. Its particles are close together but not locked in place.
Step 2: Describe particle behaviour in a liquid
In a liquid, particles can flow around each other, which is why liquids can pour and change shape. They are still relatively close together compared to gas particles.
Step 3: Choose the correct description
The correct answer is 'Particles are close together and can flow around each other', which matches the properties of the liquid state.
Method #2Process of EliminationStep 1: Identify what is being asked
We need to find the correct description of particle arrangement and movement in a liquid.
Step 2: Eliminate the solid description
'Tightly packed and vibrate in fixed positions' describes a solid, where particles cannot move freely. A liquid is not like this.
Step 3: Eliminate the gas description
'Move freely and rapidly in all directions' describes a gas, where particles are spread far apart and move quickly. This is not a liquid.
Step 4: Eliminate the impossible description
'Spread far apart and have a fixed shape' is incorrect — gases are spread far apart but do NOT have a fixed shape, and liquids definitely don't have a fixed shape either.
Step 5: Select the correct answer
The correct description is 'Particles are close together and can flow around each other', which is the defining feature of the liquid state.
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