Q: A sample contains 2.0 moles of $$\mathrm{NaCl}. $$How many formula units of $$\mathrm{NaCl}$$ are present in the sample?

$$2.0 \times 6.022 \times 10$$^{23}$$

Q: Which of the following is the correct formula for calculating percent yield in a chemical reaction?

$$\text{Percent Yield} = \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \times 100\%$$

Question 1

Which of the following best describes the difference between precision and accuracy in scientific measurements?

Accepted Answer

Precision refers to how close repeated measurements are to each other, while accuracy refers to how close a measurement is to the true value.

Question 2

A student measures the mass of a sample three times and gets values of 2.51 g, 2.50 g, and 2.52 g. The true mass is 2.70 g. Which statement best describes the student's measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which experiment provided evidence for the existence of the nucleus in the atom?

Accepted Answer

Rutherford's gold foil experiment

Question 4

Which law states that mass is neither created nor destroyed in a chemical reaction?

Accepted Answer

Law of Conservation of Mass

Question 5

A compound contains 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is the empirical formula of the compound?

Accepted Answer

$$\mathrm{CH_2O}$$

Question 6

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 7

A sample contains 2.0 moles of $$\mathrm{NaCl}. $$How many formula units of $$\mathrm{NaCl}$$ are present in the sample?

Accepted Answer

$$2.0 	imes 6.022 	imes 10$$^{23}$$

Question 8

Which separation technique would be most appropriate for separating a mixture of salt and water?

Accepted Answer

Distillation

Question 9

Which of the following is a chemical change?

Accepted Answer

Iron rusting in moist air

Question 10

A student is given a sample of magnesium and asked to predict the product when it reacts with oxygen. Which balanced equation best represents this reaction?

Accepted Answer

$$2\mathrm{Mg} + \mathrm{O}_2 \rightarrow 2\mathrm{MgO}$$

Question 11

Which of the following is the correct formula for calculating percent yield in a chemical reaction?

Accepted Answer

$$	ext{Percent Yield} = \frac{	ext{Actual Yield}}{	ext{Theoretical Yield}} 	imes 100\%$$

Question 12

Which of the following best describes the difference between an element and a compound?

Accepted Answer

An element consists of only one type of atom, while a compound consists of two or more types of atoms chemically bonded.

Question 13

A chemist needs to prepare 0.50 mol of $$\mathrm{H_2SO_4}. $$What mass of $$\mathrm{H_2SO_4} is $$required? (Molar mass of $$\mathrm{H_2SO_4} = 98.1 g/$$mol)

Accepted Answer

$$49.05\ \mathrm{g}$$

Question 14

Which of the following is NOT a derived SI unit?

Accepted Answer

Kilogram

Question 15

Which statement about the periodic table is correct?

Accepted Answer

Elements in the same group have similar chemical properties.

Question 16

A reaction produces 10.0 g of product, but the theoretical yield is 12.5 g. What is the percent yield?

Accepted Answer

$$80.0\%$$

Question 17

Which of the following is the correct balanced equation for the combustion of methane ($$\mathrm{CH_4$}$$)?

Accepted Answer

$$\mathrm{CH_4$} + 2\mathrm{O_2$} \rightarrow \mathrm{CO_2$} + 2\mathrm{H_2O}$$

Question 18

Which of the following is an example of a physical property?

Accepted Answer

Boiling point

Question 19

A mixture of sand and iron filings can be separated by which method?

Accepted Answer

Using a magnet

General Chemistry I: Study Guide for Chapters 1–4 (Exam 1 Topics)

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