Question

students in mr. kleins chemistry class are conducting an experiment to calculate the specific heat of a copper sample. mr. klein requires each lab team to repeat the experiment until their percent error is 2% or less. percent error is calculated using observed values (those students calculate from their lab results) and the true value (the accepted value based on reference). the formula for percent error is: (observed - true) x 100 / true. if the accepted value for the specific heat of copper is 0.385 j/g°c, which of the following lab teams have an unresolved problem on their hands? a. team 1: calculates 0.390 j/g°c b. team 2: calculates 0.395 j/g°c c. both teams d. neither team

Explanation:

Step1: Calculate percent - error for team 1

The formula for percent error is $\frac{\vert\text{observed}-\text{true}\vert}{\text{true}}\times100$. The true value of the specific heat of copper is $0.385\ J/g^{\circ}C$ and team 1's observed value is $0.390\ J/g^{\circ}C$. So, $\text{Percent Error}_1=\frac{\vert0.390 - 0.385\vert}{0.385}\times100=\frac{0.005}{0.385}\times100\approx1.299\%$.

Step2: Calculate percent - error for team 2

Team 2's observed value is $0.395\ J/g^{\circ}C$. So, $\text{Percent Error}_2=\frac{\vert0.395 - 0.385\vert}{0.385}\times100=\frac{0.01}{0.385}\times100\approx2.597\%$.

Step3: Check the requirements

Mr. Klein requires the percent error to be $2\%$ or less. Team 1 has a percent error of approximately $1.299\%$ which is less than $2\%$, and team 2 has a percent error of approximately $2.597\%$ which is greater than $2\%$.

Answer:

B. team 2: calculates $0.395\ J/g^{\circ}C$