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Grade 10 · unit review

Review: Solutions, Acids and Concentration

Use supplied concentration and pH models without handling chemicals.

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Bring the unit skills together

Use these 4 new cases to check your reasoning. Choices are temporary and are not saved to an account, sent to staff or recorded as school grades. Download your current review choices before leaving or reloading.

Unit review questions
1. Supplied case 5: solute amount (mol)=2.4; solution volume (L)=6, using the explicitly named quantities. Molarity equals solute moles divided by solution liters. What result follows?
Need a hint?
  • Molarity equals solute moles divided by solution liters.
  • Moles and grams are different units.
2. Supplied case 5: initial concentration (mol/L)=2.5; initial volume (L)=3; final volume (L)=10, using the explicitly named quantities. Final concentration equals initial concentration times initial liters divided by final liters. What result follows?
Need a hint?
  • Final concentration equals initial concentration times initial liters divided by final liters.
  • Final volume belongs in the denominator.
3. Supplied case 5: positive exponent a in hydronium 10^(-a) mol/L=6, using the explicitly named quantities. If hydronium concentration is 10 raised to negative a mol/L, model pH equals a. What result follows?
Need a hint?
  • If hydronium concentration is 10 raised to negative a mol/L, model pH equals a.
  • A one-unit pH difference corresponds to a tenfold concentration factor.
4. Supplied case 5: pH at 25°C=8, using the explicitly named quantities. At stated 25°C, pOH equals 14 minus pH. What result follows?
Need a hint?
  • At stated 25°C, pOH equals 14 minus pH.
  • pOH concerns hydroxide rather than hydronium.

The download contains your current choices and any checked feedback. Keep the separate transfer-task work in your own document; downloading its instructions does not mark it complete.

Use the skills in a new task

Create a four-panel explanation for “Solutions, Acids and Concentration” using one supplied case from each lesson. Include the observation, scientific mechanism or calculation, result and a limitation. You may draw and speak your explanation; all inputs are supplied.

Work on paper or in your own document. Explain the choices you made.

  • Use one supplied case from each of the four lessons.
  • Name the relevant structure, quantity or process in every panel.
  • Show calculations with units or a causal evidence chain.
  • Distinguish source facts from fictional classroom data.
  • State a model limit or a condition that would change the result.
Compare with a model response

Panel 1: Supplied case 1: solute amount (mol)=0.6; solution volume (L)=2, using the explicitly named quantities. Molarity equals solute moles divided by solution liters. What result follows? Result: 0.3 mol/L. Reasoning: Substitute the supplied values: (0.6)/(2) = 0.3 mol/L. Use final solution volume. Do not assume solute volume is zero in actual preparation. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 2: Supplied case 1: initial concentration (mol/L)=2; initial volume (L)=1; final volume (L)=4, using the explicitly named quantities. Final concentration equals initial concentration times initial liters divided by final liters. What result follows? Result: 0.5 mol/L. Reasoning: Substitute the supplied values: (2)*(1)/(4) = 0.5 mol/L. Track conserved solute, not constant concentration. This is a supplied calculation, not mixing instructions. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 3: Supplied case 1: positive exponent a in hydronium 10^(-a) mol/L=2, using the explicitly named quantities. If hydronium concentration is 10 raised to negative a mol/L, model pH equals a. What result follows? Result: 2 pH units. Reasoning: Substitute the supplied values: (2) = 2 pH units. Use the negative logarithm, not concentration multiplied by ten. These are idealized educational values. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified. Panel 4: Supplied case 1: pH at 25°C=2, using the explicitly named quantities. At stated 25°C, pOH equals 14 minus pH. What result follows? Result: 12 pOH units. Reasoning: Substitute the supplied values: 14-(2) = 12 pOH units. Keep the 25°C condition. Do not apply a constant fourteen at every temperature. Model limitation: only the stated classroom boundary and supplied observations are established; unmeasured real-world performance remains unverified.

A different response can also meet the criteria. Compare the evidence and reasoning, rather than copying the wording.