Q: Find the corresponding energy of a photon for each of the following frequencies: a. 2.2 GHz, b. 4.2 THz, c. 102.5 MHz. Use $$E = h\nu$$ with $$h = 6.626 \times 10$$^{-34}$$ J·s.

a. $$1.5 \times 10$$^{-21}$$ J; b. 2.8$$ \times $$10^{-21} J$$; c. $$6.791 \times 10$$^{-29}$$ J

Question 1

Which table correctly matches the number of electrons and protons for each ion listed (Ga$$^{3+}$$, Ba$$^{2+}$$, F$$^-$$, Po$$^{2-}$$)?

Accepted Answer

Ga$$^{3+}$$: 28 e$$^-$$, 31 p$$^+$$; Ba$$^{2+}$$: 54 e$$^-$$, 56 p$$^+$$; F$$^-$$: 10 e$$^-$$, 9 p$$^+$$; Po$$^{2-}$$: 86 e$$^-$$, 84 p$$^+$$

Question 2

Which of the following best describes the law of conservation of mass as illustrated by the reaction mixture images provided?

Accepted Answer

The total number of each type of atom remains the same before and after the reaction.

Question 3

Which image best represents the product mixture that obeys the law of conservation of mass for the reaction shown in the initial mixture?

Accepted Answer

Image 7

Question 4

A particle is projected between two electrically charged plates and bends toward the positive plate, as shown in the diagram. Is the particle an electron?

Accepted Answer

Yes, the particle is an electron.

Question 5

Which of the following statements about atomic number and mass number is correct?

Accepted Answer

Atomic number is equivalent to the number of protons while the mass number is equivalent to the sum of the number of protons and number of neutrons.

Question 6

Which of the following is an example of a chemical change as observed in the acid rain experiment with materials such as wood, vinyl, and steel?

Accepted Answer

Changes in color and texture indicate that the material underwent a chemical change.

Question 7

Which of the following statements about the classification of scientific statements is correct?

Accepted Answer

(a) Observation; (b) Theory; (c) Law; (d) Observation

Question 8

Methane (CH$$_4) $$and ethylene (C$$_2H$_2) $$are only composed of carbon and hydrogen. How much hydrogen would react with 1.78 g of carbon to produce methane and to produce ethylene? (Use the law of multiple proportions)

Accepted Answer

for CH$$_4$$: 0.299 g H; for C$$_2H$_2$$: 0.149 g H

Question 9

Calculate the atomic weight of sulfur given the following isotopes: $$^{32}S (94.99$$%, 31.972 amu), $$^{33}S (0.75$$%, 32.971 amu), $$^{34}S (4.25$$%, 33.968 amu), $$^{36}S (0.01$$%, 35.967 amu).

Accepted Answer

32.065 amu

Question 10

Which of the following isotope symbols is incorrect?

Accepted Answer

(iii) and (iv)

Question 11

Rank the following Bohr model transitions from largest to smallest frequency: I. $$n = 8 	o n = 5$$, II. $$n = 1 	o n = 4$$, III. $$n = 3 	o n = 6$$, IV. $$n = 6 	o n = 7.$$

Accepted Answer

II \u003e III \u003e I \u003e IV

Question 12

Given the orbital illustrations, identify the correct quantum numbers for each: (i) 4d$$_{yz}$$, (ii) 5s.

Accepted Answer

(i) 4d$$_{yz}$$: $$n = 4$$, $$l = 2$$; (ii) 5s: $$n = 5$$, $$l = 0$$

Question 13

Find the corresponding energy of a photon for each of the following frequencies: a. 2.2 GHz, b. 4.2 THz, c. 102.5 MHz. Use $$E = h
u$$ with $$h = 6.626 	imes 10$$^{-34}$$ J·s.

Accepted Answer

a. $$1.5 	imes 10$$^{-21}$$ J; b. 2.8$$ 	imes $$10^{-21} J$$; c. $$6.791 	imes 10$$^{-29}$$ J

Question 14

Calculate the uncertainty in the velocity for a neutron if the uncertainty in its position is 605 pm. Use $$\Delta x \cdot m_n \Delta v \geq \frac{h}{4\pi}$$, $$m_n = 1.675 	imes 10$$^{-27}$$ kg, h = 6.626$$ 	imes $$10^{-34} J$$·s.

Accepted Answer

$$\Delta v \geq 163 m/s$$

Question 15

Which of the following can eject the most number of electrons from a metal sample if the work function of the metal sample is 360 kJ/mol?

Accepted Answer

A 370 nm wavelength of strong light

Question 16

A sample of an unknown element was burned and emitted light with a frequency of 1311 THz. Which element is it? (Use $$c = \lambda 
u$$ and the provided characteristic wavelengths.)

Accepted Answer

Cd

Question 17

Determine the de Broglie wavelength of a proton traveling at the speed of light and identify the region in the electromagnetic spectrum for this wavelength. ($$\lambda = \frac{h}{mv}$$, $$m_p = 1.67 	imes 10$$^{-27}$$ kg, c = 3.00$$ 	imes $$10^8 m/s)$$

Accepted Answer

$$\lambda = 2.48 	imes 10^2$ m; radio waves

Question 18

Which of the following statements is correct regarding quantum numbers?

Accepted Answer

b & d

Question 19

Arrange the given orbitals in order of decreasing energy: 5f, 3s, 6d, 4s, 7p.

Accepted Answer

5f \u003e 6d \u003e 7p \u003e 4s \u003e 3s

General Chemistry Exam I Study Guidance: Chapters 1 & 2

Study Guide - Practice Questions

Study Guide - Flashcards