Q: A sample of propane ($$\mathrm{C_3H_8}) $$weighing 88.14 g is combusted in excess oxygen. How many liters of $$\mathrm{CO_2$}$$ are produced at STP? (Molar mass of $$\mathrm{C_3H_8} = 44.097 g/$$mol, 1 mol gas at STP = 22.4 L)

$$\displaystyle \frac{88.14}{44.097} \times 3 \times 22.4 = 134.4 L$$

Q: Which equation would you use to calculate the heat required to raise the temperature of a liquid without a phase change?

$$q = m \times c \times \Delta T$$

Question 1

Which scientist is credited with the discovery of the electron, and what experiment led to this discovery?

Accepted Answer

J.J. Thomson; Cathode ray tube experiment

Question 2

A sample of propane ($$\mathrm{C_3H_8}) $$weighing 88.14 g is combusted in excess oxygen. How many liters of $$\mathrm{CO_2$}$$ are produced at STP? (Molar mass of $$\mathrm{C_3H_8} = 44.097 g/$$mol, 1 mol gas at STP = 22.4 L)

Accepted Answer

$$\displaystyle \frac{88.14}{44.097} 	imes 3 	imes 22.4 = 134.4 L$$

Question 3

Which of the following best describes the trend in ionization energy across a period in the periodic table?

Accepted Answer

Ionization energy increases from left to right.

Question 4

What is the electron configuration for the chloride ion ($$\mathrm{Cl^-}$$)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^6$$

Question 5

Which equation would you use to calculate the heat required to melt a solid at its melting point?

Accepted Answer

$$q = m 	imes H_f$$

Question 6

If sodium ($$\mathrm{Na}) $$loses one electron to form $$\mathrm{Na^+}$$, what is the resulting electron configuration?

Accepted Answer

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

Question 7

Which of the following statements about isotopes is correct?

Accepted Answer

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

Question 8

Which section of a heating curve (like the one shown in the graph) represents the phase change from liquid to gas?

Accepted Answer

The flat section at the boiling point.

Question 9

A zoo wants to exchange 2 zebras for koalas using the following barter system: 1 zebra = 2 lions, 3 lions = 5 tigers, 2 tigers = 1 elephant, 1 elephant = 3 koalas. How many koalas will the zoo get for 2 zebras?

Accepted Answer

6 koalas

Question 10

Which of the following best describes the periodic law?

Accepted Answer

The properties of elements recur in a repeating pattern when arranged by atomic number.

Question 11

Which of the following is the correct order of filling for electron sublevels according to the Aufbau principle?

Accepted Answer

$$1s \rightarrow 2s \rightarrow 2p \rightarrow 3s \rightarrow 3p \rightarrow 4s \rightarrow 3d$$

Question 12

Which of the following best explains why the radius of a sodium ion ($$\mathrm{Na^+}) is $$smaller than that of a sodium atom?

Accepted Answer

The sodium ion has fewer electrons, resulting in less electron-electron repulsion.

Question 13

Which equation would you use to calculate the heat required to raise the temperature of a liquid without a phase change?

Accepted Answer

$$q = m 	imes c 	imes \Delta T$$

Question 14

Which of the following is the correct electron configuration for potassium ($$\mathrm{K}$$, atomic number 19)?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^6$$\ $$3s^2$$\ $$3p^6$$\ $$4s^1$$

Question 15

Which of the following statements about the Bohr model of the atom is correct?

Accepted Answer

Electrons occupy fixed orbits with quantized energies.

Introductory Chemistry: Atomic Structure, Periodic Table, and Electron Configuration (Week 3 Study Guide)

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