Q: A sample of water has a mass of 250 g. Convert this mass to kilograms using the correct SI prefix and show your calculation.

$$250 \times 10$$^{-3}$$ \text{ kg} = 0.25 \text{ kg}$$

Q: Balance the following chemical equation: $$\text{C}_2\text{H}_6 + \text{O}_2 \rightarrow \text{CO}_2 + \text{H}_2\text{O}$$

$$2\text{C}_2\text{H}_6 + 7\text{O}_2 \rightarrow 4\text{CO}_2 + 6\text{H}_2\text{O}$$

Q: Which of the following is a precipitation reaction?

$$\text{AgNO}_3(aq) + \text{NaCl}(aq) \rightarrow \text{AgCl}(s) + \text{NaNO}_3(aq)$$

Q: Calculate the heat required to raise the temperature of 100 g of water from 25°C to 75°C. ($$c = 4.18 \text{ J/g} \cdot \text{°C})$$

$$Q = mc\Delta T = 100 \times 4.18 \times (75-25) = 20,900 \text{ J}$$

Q: Which of the following is the correct formula for calculating the molarity of a solution?

$$\text{Molarity} = \frac{\text{moles of solute}}{\text{liters of solution}}$$

Question 1

A sample of water has a mass of 250 g. Convert this mass to kilograms using the correct SI prefix and show your calculation.

Accepted Answer

$$250 	imes 10$$^{-3}$$ 	ext{ kg} = 0.25 	ext{ kg}$$

Question 2

Which of the following statements about significant figures is correct when multiplying 2.50 (3 sig figs) by 0.040 (2 sig figs)?

Accepted Answer

The answer should have 2 significant figures.

Question 3

Which of the following best describes the difference between atomic number and mass number?

Accepted Answer

Atomic number is the number of protons; mass number is the sum of protons and neutrons.

Question 4

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

Accepted Answer

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

Question 5

Balance the following chemical equation: $$	ext{C}_2	ext{H}_6 + 	ext{O}_2 ightarrow 	ext{CO}_2 + 	ext{H}_2	ext{O}$$

Accepted Answer

$$2	ext{C}_2	ext{H}_6 + 7	ext{O}_2 ightarrow 4	ext{CO}_2 + 6	ext{H}_2	ext{O}$$

Question 6

Which of the following is a precipitation reaction?

Accepted Answer

$$	ext{AgNO}_3(aq) + 	ext{NaCl}(aq) ightarrow 	ext{AgCl}(s) + 	ext{NaNO}_3(aq)$$

Question 7

Which of the following elements has the highest electronegativity?

Accepted Answer

Fluorine

Question 8

Which statement best explains why atomic radius decreases across a period in the periodic table?

Accepted Answer

Increasing nuclear charge pulls electrons closer to the nucleus.

Question 9

Which electron configuration represents a noble gas?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^6$$

Question 10

Which of the following molecules has a bent molecular geometry?

Accepted Answer

$$	ext{H}_2	ext{O}$$

Question 11

Which intermolecular force is strongest in liquid water?

Accepted Answer

Hydrogen bonding

Question 12

A balloon contains 2.0 L of gas at 1.0 atm. If the pressure is increased to 4.0 atm at constant temperature, what is the new volume?

Accepted Answer

$$0.5 	ext{ L}$$

Question 13

Which of the following best describes the Kinetic Molecular Theory of gases?

Accepted Answer

Gas particles are in constant, random motion and collisions are elastic.

Question 14

Calculate the heat required to raise the temperature of 100 g of water from 25°C to 75°C. ($$c = 4.18 	ext{ J/g} \cdot 	ext{°C})$$

Accepted Answer

$$Q = mc\Delta T = 100 	imes 4.18 	imes (75-25) = 20,900 	ext{ J}$$

Question 15

Which of the following phase changes is endothermic?

Accepted Answer

Melting

Question 16

Which of the following best describes a redox reaction?

Accepted Answer

A reaction in which electrons are transferred between species.

Question 17

Which of the following is the correct formula for calculating the molarity of a solution?

Accepted Answer

$$	ext{Molarity} = \frac{	ext{moles of solute}}{	ext{liters of solution}}$$

Question 18

Which of the following best explains why ice floats on water?

Accepted Answer

Ice is less dense than liquid water due to its hydrogen-bonded structure.

Question 19

Which of the following is the correct expression for the ideal gas law?

Accepted Answer

$$PV = nRT$$

Question 20

Which of the following best describes the process of ionization energy?

Accepted Answer

The energy required to remove an electron from a gaseous atom.

General Chemistry I: Comprehensive Study Notes (Chapters 1–11)

Guida di studio - Domande di pratica

Study guide - Flashcard