Question 1

Which of the following best describes the difference between a scientific law and a scientific theory?

Accepted Answer

A scientific law is a summary of observed phenomena, while a scientific theory provides an explanation for those phenomena.

Question 2

A sample contains only one type of atom and cannot be broken down into simpler substances by chemical means. Which type of matter is this?

Accepted Answer

Element

Question 3

Which of the following is an example of a chemical change?

Accepted Answer

Iron rusting in moist air

Question 4

A student measures the mass of a metal block as $$45.67\ \mathrm{g}$$ and its volume as $$12.3\ \mathrm{cm}^3. $$What is the density of the metal, rounded to the correct number of significant figures?

Accepted Answer

$$3.71\ \mathrm{g/cm}^3$$

Question 5

Which of the following statements about the Law of Conservation of Mass is correct?

Accepted Answer

The total mass remains constant during a chemical reaction.

Question 6

Which experiment led to the discovery of the electron, and what was the key observation?

Accepted Answer

Thomson's cathode ray experiment; cathode rays were deflected by electric and magnetic fields.

Question 7

Which of the following best describes an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons

Question 8

A student needs to convert $$5.00\ \mathrm{cm} to $$meters. What is the correct conversion?

Accepted Answer

$$0.0500\ \mathrm{m}$$

Question 9

Which of the following elements is most likely to form a $$2^+$$ cation?

Accepted Answer

Magnesium ($$\mathrm{Mg})$$

Question 10

Which of the following is a diatomic element in its natural state?

Accepted Answer

Oxygen ($$\mathrm{O}_2)$$

Question 11

A compound is formed from sodium and chlorine. Which type of bond is present in this compound, and what is its chemical formula?

Accepted Answer

Ionic bond; $$\mathrm{NaCl}$$

Question 12

Which of the following best describes the structure of a crystalline solid?

Accepted Answer

Particles are arranged in a repeating, orderly pattern.

Question 13

A sample of water is heated from $$25^\circ\mathrm{C} to$$ $$100^\circ\mathrm{C}$$ and then boiled to steam. Which of the following statements is true about the energy changes involved?

Accepted Answer

Energy is absorbed during both heating and boiling.

Question 14

Which of the following is the correct molar mass of $$\mathrm{CO}_2 ($$carbon dioxide)? (Atomic masses: C = 12.01 g/mol, O = 16.00 g/mol)

Accepted Answer

$$44.01\ \mathrm{g/mol}$$

Question 15

A sample contains $$1.204 	imes 10$$^{24}$$ molecules of water. How many moles of water are present? ($$\mathrm{Avogadro's\ number} = 6.022 	imes $$10^{23}$$\ \mathrm{mol}^{-1}$$)

Accepted Answer

$$2.00\ \mathrm{mol}$$

Question 16

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

Accepted Answer

Accuracy is how close measurements are to the true value; precision is how close measurements are to each other.

Question 17

Which of the following statements about ionic and covalent compounds is correct?

Accepted Answer

Ionic compounds have high melting points due to strong electrostatic forces between ions.

Question 18

A student wants to convert $$2.00\ \mathrm{in}^3 to$$ $$\mathrm{cm}^3. $$Given $$1\ \mathrm{in} = 2.54\ \mathrm{cm}$$, what is the correct conversion?

Accepted Answer

$$16.4\ \mathrm{cm}^3$$

Question 19

Which of the following is true about the properties of compounds compared to the elements that form them?

Accepted Answer

Compounds have properties that are often very different from the elements that make them up.

Question 20

Which of the following best describes the conclusion from Rutherford's gold foil experiment?

Accepted Answer

Atoms have a small, dense, positively charged nucleus.

General Chemistry I: Unit 1 Study Guide (Chapters 1–3)

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