A graduated cylinder contains 92 milliliters (mL) of solution. If 38 mL of the solution evaporates, what is the remaining...

1. TRANSLATE the problem information

• Given information:
  • Initial volume in graduated cylinder: \(\mathrm{92\,mL}\)
  • Volume that evaporates: \(\mathrm{38\,mL}\)
  • Need to find: remaining volume

• What this tells us: We have two quantities and need to determine what's left after one amount is removed.

2. INFER the approach

• Key insight: Evaporation means liquid turns to gas and leaves the container
• This means the volume in the cylinder decreases
• When we want to find what remains after something is removed, we subtract
• Mathematical operation needed: \(\mathrm{92\,mL - 38\,mL}\)

3. Calculate the remaining volume

• Remaining volume = Initial volume - Evaporated volume
• Remaining volume = \(\mathrm{92 - 38 = 54\,mL}\)

Answer: D (54)

Why Students Usually Falter on This Problem

Most Common Error Path:

Weak INFER skill: Students misunderstand the relationship between evaporation and volume change. They might think evaporation means adding liquid (confusion about the process) or they automatically add the two numbers without considering what the situation means physically.

This leads them to calculate \(\mathrm{92 + 38 = 130}\), causing them to select Choice A (130).

Second Most Common Error:

Poor TRANSLATE reasoning: Students correctly understand that subtraction is needed but get confused about what the question is asking for. They might report the original volume (\(\mathrm{92\,mL}\)) or the evaporated amount (\(\mathrm{38\,mL}\)) instead of calculating the difference.

This causes them to select Choice B (92) or Choice C (38) without performing any calculation.

The Bottom Line:

This problem tests whether students can connect the physical process of evaporation to the mathematical operation of subtraction. The key is recognizing that "evaporates" means "leaves the container," which requires subtraction to find what remains.