Q: A photon has a wavelength of $$4.00 \times 10$$^{-7}$$ \ \mathrm{m}. $$What is its energy? ($$h = 6.626 \times 10$$^{-34}$$ \ \mathrm{J\cdot s}$$, $$c = 3.00 \times 10^8$ \ \mathrm{m/s})$$

$$4.97 \times 10$$^{-19}$$ \ \mathrm{J}$$

Question 1

Which of the following statements best describes a strong electrolyte in aqueous solution?

Accepted Answer

It completely dissociates into ions in water.

Question 2

A student mixes solutions of $$\mathrm{Na_2SO_4}$$ and $$\mathrm{$$BaCl_2$$}. $$Which of the following is the correct net ionic equation for the reaction that occurs?

Accepted Answer

$$\mathrm{Ba$$^{2+}$$ (aq) + SO_4$^{2-} (aq) \rightarrow $$BaSO_4$$ (s)}$$

Question 3

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

Accepted Answer

$$\mathrm{CH_3COOH} ($$acetic acid)

Question 4

A 25.0 mL sample of 0.200 M $$\mathrm{HCl} is $$titrated with 0.100 M $$\mathrm{NaOH}. $$What volume of $$\mathrm{NaOH} is $$required to reach the equivalence point?

Accepted Answer

50.0 mL

Question 5

Which of the following correctly identifies the oxidizing agent in the reaction: $$\mathrm{Zn (s) + Cu$$^{2+}$$ (aq) \rightarrow Zn$$^{2+}$$ (aq) + Cu (s)}$$?

Accepted Answer

$$\mathrm{Cu$$^{2+}$$ (aq)}$$

Question 6

A solution is prepared by diluting 10.0 mL of 6.00 M $$\mathrm{H_2SO_4} to a $$final volume of 250.0 mL. What is the final molarity?

Accepted Answer

0.240 M

Question 7

Which of the following is a correct statement about exothermic reactions?

Accepted Answer

They release heat to the surroundings, and $$\Delta H is $$negative.

Question 8

A 50.0 g sample of water is heated from 25.0 $$^\circC to 75.0$$ $$^\circC. If $$the specific heat of water is $$4.18 \ \mathrm{J/g\cdot ^\circ C}$$, how much heat is absorbed?

Accepted Answer

$$10,450 \ \mathrm{J}$$

Question 9

Which of the following is a state function?

Accepted Answer

Enthalpy ($$\Delta H)$$

Question 10

Given the following standard enthalpies of formation: $$\Delta H_f^\circ (\mathrm{CO_2$ (g)}) = -393.5 \ \mathrm{kJ/mol}$$, $$\Delta H_f^\circ (\mathrm{H_2O (l)}) = -285.8 \ \mathrm{kJ/mol}$$, $$\Delta H_f^\circ (\mathrm{C_2H_5OH (l)}) = -277.0 \ \mathrm{kJ/mol}$$, calculate $$\Delta H_{rxn}^\circ$$ for the combustion of ethanol: $$\mathrm{C_2H_5OH (l) + 3 O_2$ (g) \rightarrow 2 CO_2$ (g) + 3 H_2O (l)}.$$

Accepted Answer

$$-1367.1 \ \mathrm{kJ}$$

Question 11

Which of the following equations correctly relates the frequency ($$
u$$), wavelength ($$\lambda$$), and speed of light ($$c) $$for electromagnetic radiation?

Accepted Answer

$$
u \lambda = c$$

Question 12

A photon has a wavelength of $$4.00 	imes 10$$^{-7}$$ \ \mathrm{m}. $$What is its energy? ($$h = 6.626 	imes 10$$^{-34}$$ \ \mathrm{J\cdot s}$$, $$c = 3.00 	imes 10^8$ \ \mathrm{m/s})$$

Accepted Answer

$$4.97 	imes 10$$^{-19}$$ \ \mathrm{J}$$

Question 13

Which set of quantum numbers is NOT allowed for an electron in an atom?

Accepted Answer

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

Question 14

Which principle states that no two electrons in an atom can have the same set of four quantum numbers?

Accepted Answer

Pauli exclusion principle

Question 15

Which of the following electron configurations represents a ground state atom of nitrogen ($$Z=7$$)?

Accepted Answer

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

Question 16

Which of the following best describes Hund’s rule?

Accepted Answer

Electrons fill degenerate orbitals singly before pairing.

Question 17

Which of the following is the correct order of increasing energy for the electromagnetic spectrum regions listed?

Accepted Answer

Radio \u003c Visible \u003c Ultraviolet \u003c X-rays

Question 18

A reaction has $$\Delta H = -250 \ \mathrm{kJ}$$ and $$q = -250 \ \mathrm{kJ} at $$constant pressure. Which of the following is true?

Accepted Answer

The reaction is exothermic and releases 250 kJ of heat.

Question 19

Which of the following best describes the Heisenberg uncertainty principle?

Accepted Answer

It is impossible to know both the exact position and momentum of an electron simultaneously.

Question 20

Which of the following is the correct expression for the energy change in a reaction using bond enthalpies?

Accepted Answer

$$\Delta H_{rxn} = \Sigma 	ext{(bond enthalpies of bonds broken)} - \Sigma 	ext{(bond enthalpies of bonds formed)}$$

General Chemistry Study Notes: Chapters 4, 5, and 6 Review

Guida di studio - Domande di pratica

Study guide - Flashcard