Q: Which of the following is a correct example of using dimensional analysis for a unit conversion?

$$0.00510 \ \mathrm{mol} \times \frac{58.44 \ \mathrm{g}}{1 \ \mathrm{mol}} = 0.299 \ \mathrm{g}$$

Question 1

Which of the following best describes the correct use of significant figures when solving a stoichiometry problem involving multiple steps?

Accepted Answer

Only round the final answer to the correct number of significant figures, not the intermediate steps.

Question 2

A student is converting 0.00510 mol of NaCl to grams. Which of the following best demonstrates the correct use of zeros and significant figures in the answer?

Accepted Answer

0.299 g (showing the zero in front of the decimal)

Question 3

Which of the following is NOT allowed during the Chem 136 Exam 3?

Accepted Answer

Using a cell phone as a calculator

Question 4

When expressing the number 21500 in scientific notation for this exam, which is the correct format?

Accepted Answer

$$2.15 	imes 10^4$

Question 5

A problem asks you to convert 0.23 L to mL. Which of the following is the correct answer, following the exam's guidelines for zeros?

Accepted Answer

230 mL

Question 6

Which of the following best describes the correct approach to solving a problem that does NOT involve an equation, according to the exam guidelines?

Accepted Answer

Use dimensional analysis to solve the problem.

Question 7

Why is it important to use the atomic masses as given on the periodic table provided during the exam?

Accepted Answer

Because rounding off atomic masses can lead to significant errors in calculations.

Question 8

A student writes their answer as $$1.0 	imes 10^1$ for a calculation. According to the exam guidelines, is this acceptable?

Accepted Answer

No, because exponents of 1, 0, or -1 should not be used in scientific notation.

Question 9

If you are asked to convert 3.50 grams of a substance to moles using its molar mass, which of the following is the correct sequence of steps according to the exam's problem-solving guidelines?

Accepted Answer

Write the equation, substitute the numbers with units, and box the final answer with correct sig figs.

Question 10

Which of the following is a correct example of using dimensional analysis for a unit conversion?

Accepted Answer

$$0.00510 \ \mathrm{mol} 	imes \frac{58.44 \ \mathrm{g}}{1 \ \mathrm{mol}} = 0.299 \ \mathrm{g}$$

Question 11

During the exam, what should you do if you need to use the restroom?

Accepted Answer

Use the restroom before the exam begins.

Question 12

Which of the following is the best reason for not sharing calculators during the exam?

Accepted Answer

To prevent academic dishonesty and ensure fairness.

Question 13

If a calculation yields the answer 0.00510, how should you write it to follow the exam's significant figure and zero guidelines?

Accepted Answer

0.00510

Question 14

Which of the following best describes the exam format for Chem 136 Exam 3?

Accepted Answer

Multiple choice, short answer, and show-your-work problems.

Question 15

Why is neatness important when submitting your exam?

Accepted Answer

Points will be deducted if work is messy.

Question 16

Which of the following is the correct way to express 0.00023 in scientific notation according to the exam guidelines?

Accepted Answer

$$2.3 	imes 10$$^{-4}$$

Question 17

If you are asked to solve a grams-moles-number of particles problem, which method should you use?

Accepted Answer

Dimensional analysis

Question 18

Which of the following is a correct example of a boxed answer with correct significant figures?

Accepted Answer

$$\boxed{2.15 	imes 10^4$}$$

Question 19

Why should you not use unit conversions to determine significant figures in your final answer?

Accepted Answer

Because significant figures should be determined by the measured values, not conversion factors.

Question 20

Which of the following is the best practice when preparing for Chem 136 Exam 3?

Accepted Answer

Study all lecture material and homework before using the practice test as a final check.

Exam 3 Information and Problem Solving Guidelines for General Chemistry

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