Q: Which equation would you use to calculate the density of a liquid if you know its mass and volume?

$$ \text{Density} = \frac{\text{Mass}}{\text{Volume}} $$

Q: A sample of water is heated from 25°C to 75°C. If the mass of water is 100 g and the specific heat capacity is $$4.18\ \text{J/g} \cdot \text{°C}$$, how much heat is absorbed?

$$ q = 100 \times 4.18 \times (75 - 25) = 20,900\ \text{J} $$

Q: Which of the following is a correct balanced equation for the combustion of methane ($$\text{CH}_4) in $$oxygen?

$$ \text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O} $$

Q: A gas occupies 2.0 L at 1.0 atm and 300 K. What will its volume be at 2.0 atm and 300 K, assuming ideal behavior?

$$ V_2$ = \frac{V_1$ \times P_1$}{P_2$} = \frac{2.0 \times 1.0}{2.0} = 1.0\ \text{L} $$

Q: Which of the following statements about acids and bases is correct according to the Bronsted-Lowry definition?

An acid is a substance that donates a proton ($$\text{H}^+$$), and a base is a substance that accepts a proton.

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 student measures the mass of a sample as 12.50 g, 12.48 g, and 12.51 g in three trials. The true mass is 12.80 g. Which statement best describes the measurements?

Accepted Answer

The measurements are precise but not accurate.

Question 3

Which equation would you use to calculate the density of a liquid if you know its mass and volume?

Accepted Answer

$$ 	ext{Density} = \frac{	ext{Mass}}{	ext{Volume}} $$

Question 4

A sample of water is heated from 25°C to 75°C. If the mass of water is 100 g and the specific heat capacity is $$4.18\ 	ext{J/g} \cdot 	ext{°C}$$, how much heat is absorbed?

Accepted Answer

$$ q = 100 	imes 4.18 	imes (75 - 25) = 20,900\ 	ext{J} $$

Question 5

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 6

A compound contains 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. What is its empirical formula?

Accepted Answer

$$ 	ext{CH}_2	ext{O} $$

Question 7

Which of the following is a correct balanced equation for the combustion of methane ($$	ext{CH}_4) in $$oxygen?

Accepted Answer

$$ 	ext{CH}_4 + 2	ext{O}_2 ightarrow 	ext{CO}_2 + 2	ext{H}_2	ext{O} $$

Question 8

Which of the following best describes a solution?

Accepted Answer

A solution is a homogeneous mixture of a solute dissolved in a solvent.

Question 9

Which intermolecular force is responsible for the high boiling point of water compared to other similar-sized molecules?

Accepted Answer

Hydrogen bonding

Question 10

A gas occupies 2.0 L at 1.0 atm and 300 K. What will its volume be at 2.0 atm and 300 K, assuming ideal behavior?

Accepted Answer

$$ V_2$ = \frac{V_1$ 	imes P_1$}{P_2$} = \frac{2.0 	imes 1.0}{2.0} = 1.0\ 	ext{L} $$

Question 11

Which of the following is the correct expression for the equilibrium constant ($$K_{eq}) $$for the reaction $$aA + bB \rightleftharpoons cC + dD$$?

Accepted Answer

$$ K_{eq} = \frac{[C]^c [D]^d}{[A]^a [B]^b} $$

Question 12

Which of the following statements about acids and bases is correct according to the Bronsted-Lowry definition?

Accepted Answer

An acid is a substance that donates a proton ($$	ext{H}^+$$), and a base is a substance that accepts a proton.

Question 13

A radioactive isotope has a half-life of 10 years. If you start with 80 g, how much will remain after 30 years?

Accepted Answer

$$ 80 	imes \left(\frac{1}{2}\$$right)^3$$ = 10\ 	ext{g} $$

Question 14

Which of the following best explains why network covalent solids (like diamond) have very high melting points?

Accepted Answer

They have extensive covalent bonding throughout the entire structure.

Question 15

Which of the following is the correct formula for calculating the pH of a solution given the hydronium ion concentration?

Accepted Answer

$$ 	ext{pH} = -\log_{10}[	ext{H}_3	ext{O}^+] $$

Question 16

Which of the following best describes the effect of increasing temperature on the solubility of a solid solute in water?

Accepted Answer

Solubility always increases with increasing temperature.

Question 17

Which of the following is a correct statement about the Law of Conservation of Mass?

Accepted Answer

Mass is neither created nor destroyed during a chemical reaction.

Question 18

A 0.5 M solution of NaCl is diluted to a final volume of 1.0 L. If the initial volume was 0.25 L, what is the final concentration?

Accepted Answer

$$ C_2$ = \frac{C_1$ V_1$}{V_2$} = \frac{0.5 	imes 0.25}{1.0} = 0.125\ 	ext{M} $$

General Chemistry I: Comprehensive Curriculum Map and Study Guide

Guida di studio - Domande di pratica

Study guide - Flashcard