Q: Calculate the energy of 1 mole of photons with a frequency of $$5.0 \times 10$$^{14}$$\ \mathrm{s}^{-1}.$$

$$1.99 \times 10^5$\ \mathrm{J}$$

Question 1

Which of the following compounds is a strong electrolyte when dissolved in water?

Accepted Answer

Hydrochloric acid, $$\mathrm{HCl}$$

Question 2

A 25.0 mL sample of $$0.50\ \mathrm{M}$$ sodium hydroxide is required to titrate $$250.0\ \mathrm{mL} of a $$solution of hydrochloric acid. What is the concentration of hydrochloric acid?

Accepted Answer

$$0.050\ \mathrm{M}$$

Question 3

Which element is reduced in the following reaction?

$$\mathrm{K_2Cr_2O_7} + 4\mathrm{H_2SO_3} + 3\mathrm{K_2SO_3} \rightarrow 2\mathrm{Cr_2$(SO_4$)_3} + 4\mathrm{H_2SO_4} + \mathrm{K_2SO_4} + 4\mathrm{H_2O}$$

Accepted Answer

Cr

Question 4

A reaction is carried out in a sealed container with a movable piston, keeping the pressure constant at $$1.0\ \mathrm{atm}. If$$ $$2\mathrm{NH_3$}(g) \rightarrow \mathrm{N_2$}(g) + 3\mathrm{H_2$}(g)$$, and $$0.50\ \mathrm{mol} of$$ $$\mathrm{NH_3$}$$ reacts, what is the change in volume at $$25^\circ\mathrm{C}$$?

Accepted Answer

$$6.0\ \mathrm{L}$$

Question 5

Which of the following best describes the energy change when $$\mathrm{H_2O}(l)$$ freezes to $$\mathrm{H_2O}(s) at$$ $$0^\circ\mathrm{C}$$?

Accepted Answer

The process is exothermic; $$\Delta H \u003c 0$$

Question 6

Calculate the energy of 1 mole of photons with a frequency of $$5.0 	imes 10$$^{14}$$\ \mathrm{s}^{-1}.$$

Accepted Answer

$$1.99 	imes 10^5$\ \mathrm{J}$$

Question 7

Which of the following types of electromagnetic radiation has the lowest frequency?

Accepted Answer

Radio waves

Question 8

A speaker is vibrating at a frequency of $$600\ \mathrm{Hz}. $$What is the wavelength of the sound produced if the speed of sound is $$344\ \mathrm{m/s}$$?

Accepted Answer

$$0.573\ \mathrm{m}$$

Question 9

Which of the following is a direct application of the photoelectric effect?

Accepted Answer

Solar cells

Question 10

Which of the following elements has $$f$$ electrons in its ground state?

Accepted Answer

Ce

Question 11

Choose the correct set of four quantum numbers for the $$3p$$ electron in silicon ($$Z=14).$$

Accepted Answer

$$n=3,\ l=1,\ m_l=0,\ m_s=+\frac{1}{2}$$

Question 12

How many unpaired electrons does cobalt ($$\mathrm{Co}) $$have in its ground state?

Accepted Answer

3

Question 13

What is the electron configuration of vanadium ($$\mathrm{V}$$)?

Accepted Answer

$$[\mathrm{Ar}]4s^2$ 3d^3$

Question 14

How many electrons does it take to fill the fourth energy level (shell) in an atom?

Accepted Answer

32

Question 15

Given the following standard enthalpies of formation: $$\Delta H_f^\circ(\mathrm{C_4H_{10}}) = -199\ \mathrm{kJ/mol}$$, $$\Delta H_f^\circ(\mathrm{CO_2$}) = -393.5\ \mathrm{kJ/mol}$$, $$\Delta H_f^\circ(\mathrm{H_2O}) = -241.8\ \mathrm{kJ/mol}$$, calculate the enthalpy of combustion of liquid butane ($$\mathrm{C_4H_{10}}$$):

$$\mathrm{C_4H_{10}}(l) + 6.5\mathrm{O_2$}(g) \rightarrow 4\mathrm{CO_2$}(g) + 5\mathrm{H_2O}(g)$$

Accepted Answer

$$-2657\ \mathrm{kJ/mol}$$

Question 16

A $$700\ \mathrm{g}$$ block of ice at $$0^\circ\mathrm{C} is $$placed in a thermos containing $$800\ \mathrm{mL} of $$tea. If $$420\ \mathrm{g} of $$ice melts before equilibrium is reached and the final temperature is $$0^\circ\mathrm{C}$$, what is the amount of heat required to melt $$420\ \mathrm{g} of $$ice? (Heat of fusion of water is $$79.72\ \mathrm{cal/g})$$

Accepted Answer

$$33,482\ \mathrm{cal}$$

Question 17

Which of the following metals will react with $$\mathrm{Cu$$^{2+}$$}$$ ions in solution to produce copper metal? (Refer to the activity series.)

Accepted Answer

Zn

Question 18

Which of the following best explains why sodium metal reacts vigorously with water, but copper does not?

Accepted Answer

Sodium is higher than copper in the activity series, so it is more easily oxidized.

Question 19

Which of the following statements about the quantum numbers is correct?

Accepted Answer

The magnetic quantum number $$m_l$$ can have values from $$-l to$$ $$+l$$ including zero.

General Chemistry Exam 2 Study Guide

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