CH 301 Unit 0: Approximations and Percent Error

Flashcards covering key approximation techniques, percent error formulas, and molar mass estimation strategies from the CH 301 Unit 0 review notes.

Percent Error Formula

A formula used to estimate error in approximations, defined as $\text{\% Error} = \frac{\text{approximation} - \text{exact value}}{\text{exact value}} \times 100$.

Atomic Mass Rounding

The practice of rounding atomic masses of individual elements to simpler values (such as integers or simple decimals) to quickly estimate a compound's molar mass.

AuF3 Molar Mass Approximation

An estimated calculation of the molar mass of $\text{AuF}_3$ using rounded atomic masses ($\text{Au} \approx 200$, $\text{F} \approx 20$) to quickly obtain $\approx 260\,\text{g}$, compared to the exact molar mass of $253.964\,\text{g}$.

SCl6 Molar Mass Approximations

Calculations of the molar mass of $\text{SCl}_6$ demonstrating the trade-off between precision and speed: $244.76\,\text{g/mol}$ (exact), $245\,\text{g/mol}$ (using $32 + 6 \times 35.5$), or $240\,\text{g/mol}$ (using $30 + 6 \times 35$).

Carbon Atomic Mass Rounding Error

Rounding Carbon ($12.011 \rightarrow 12$) introduces a higher relative discrepancy error rate ($\approx 0.1\%$) when rounded to an integer atomic mass compared to elements like Nitrogen, Oxygen, or Fluorine.

Avogadro's Number Approximation Error

Approximating Avogadro's number as $1 \times 10^{24}$, which results in an error rate of $66.1\%$ (significantly greater than a $10\%$ error threshold).