Investigating Matter — Chapter quiz · Physical Science: Chemistry, Grade 11

Build the measurement, classification, and evidence skills used throughout chemistry.

Problem 1

Convert 75.0 mL to liters.
Hints

Write the relationship first; substitute with consistent units.

Answer and explanation

0.075 L

75/1000 = 0.0750.

Problem 2

Why are five readings from one miscalibrated balance insufficient to establish accuracy?
Answer and explanation

Repetition checks precision but can preserve systematic bias. Check a known reference or an independent method.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 3

Independent chapter check: An unknown has mass 37.5 g at volume 15.0 mL. Three repeat densities cluster near 2.50 g/mL, but the independently certified reference is 2.80 g/mL. Calculate density and explain the evidence limits.
Answer and explanation

Density is 37.5/15.0 = 2.50 g/mL. Repetition supports precision, but the difference from 2.80 suggests a method/reference comparison issue; check calibration, conditions and uncertainties rather than claim identity from one property.

Density is 37.5/15.0 = 2.50 g/mL. Repetition supports precision, but the difference from 2.80 suggests a method/reference comparison issue; check calibration, conditions and uncertainties rather than claim identity from one property.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the chemical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 4

How can two clear liquids differ as pure substances versus mixtures?
Answer and explanation

Clarity indicates no visible separate regions, not purity. Composition and properties across separation or analysis distinguish them.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 5

Select a method to separate insoluble chalk from water and explain it.
Answer and explanation

Filter the mixture; large chalk particles remain as residue while water passes through.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

Problem 6

Independent chapter check: A mixture contains 6.00 g salt and 4.00 g sand. You recover 5.10 g of dry salt-containing material. Calculate apparent salt recovery and explain why its purity remains uncertain.
Answer and explanation

Apparent recovery is 5.10/6.00 ×100 = 85.0%. The calculation treats the recovered mass as salt, but residual sand or other substances require a separate purity test. Distinguish mass loss from composition evidence.

Apparent recovery is 5.10/6.00 ×100 = 85.0%. The calculation treats the recovered mass as salt, but residual sand or other substances require a separate purity test. Distinguish mass loss from composition evidence.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the chemical mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

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