### 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?

**Possible Answers:**

**Correct answer:**

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?

**Possible Answers:**

Neither precise nor accurate

Precise and accurate

Accurate but not precise

Precise but not accurate

**Correct answer:**

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 #11 : 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?

**Possible Answers:**

Accurate but not precise

Precise and accurate

Neither precise nor accurate

Precise but not accurate

**Correct answer:**

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 #11 : Laboratory Techniques And Analysis

Find the volume that of carbon dioxide will occupy if it's density is .

**Possible Answers:**

**Correct answer:**

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 #13 : Laboratory Techniques And Analysis

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?

**Possible Answers:**

**Correct answer:**

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 #12 : Laboratory Techniques And Analysis

Place the following metric prefixes in order from smallest to largest:

k, M, m, n

**Possible Answers:**

n, m, k, M

m, n, k, M

n, M, k, m

n, k, M, m

**Correct answer:**

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).

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