All AP Chemistry Resources
Example Questions
Example Question #11 : Data Analysis And Other Calculations
Working in the laboratory, a student finds the density of pure aluminum to be . The accepted value for the density of aluminum is . What was the student's percent error?
To find the percent error, the formula is:
Therefore we plug in the values given:
Therefore, the correct answer including significant figures is
Example Question #11 : Laboratory Techniques And Analysis
The table shows the data obtained by three groups when finding the boiling point of methanol. The accepted value is . Is group A precise, accurate or both?
Precise but not accurate
Precise and accurate
Neither precise nor accurate
Accurate but not precise
Precise but not accurate
Group A's values are precise because the data values are all close to each other, but it is not accurate because it none of them is near the accepted value.
Example Question #12 : Laboratory Techniques And Analysis
The table shows the data obtained by three groups when attempting to find the boiling point of methanol. The accepted value is . Is group C precise, accurate, both, or neither?
Accurate but not precise
Precise and accurate
Precise but not accurate
Neither precise nor accurate
Precise and accurate
Group C is precise because all of their values are close to one another. Their data is also accurate because their values are all near the accepted value. Therefore group C is both accurate and precise.
Example Question #13 : Calculations
Find the volume that of carbon dioxide will occupy if it's density is .
Remember:
Rearrange the equation to solve for volume:
Plug in the values given in the problem:
However, we must take into account significant figures. Because both our given values have 3 significant figures, our answer must have 3 significant figures.
Therefore after rounding the correct answer is:
Example Question #15 : Data Analysis And Other Calculations
A student experimentally determines the specific heat of water to be . He then looks up the accepted value and finds that it is . What was the student's percent error?
The formula for percent error is:
Plug in the given values and solve:
Therefore, after accounting for significant figures the correct answer is
Example Question #13 : Laboratory Techniques And Analysis
Place the following metric prefixes in order from smallest to largest:
k, M, m, n
n, k, M, m
n, M, k, m
n, m, k, M
m, n, k, M
n, m, k, M
Remember the saying "King Henry Died by Drinking Chocolate Milk". This is referencing the order of metric prefixes: kilo, hecto, deca, deci, centi, milli. Or in their abbreviations: k, h, da, d, c, m.
You also need to know nano (n) which is .
The final one you need to know for this question is Mega (M) which is .
Therefore the correct answer is: n, m, k, M (nano, milli, kilo, Mega).