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# Convert between energy units:a. 231 cal to kJb. 132 × 104 ISBN: 9780321809247 1

## Solution for problem 34E Chapter 6

Chemistry: A Molecular Approach | 3rd Edition

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Problem 34E

Convert between energy units:

a. 231 cal to kJ

b. 132 × 104 kJ to kcal

c. 4.99 × 103 kJ to kWh

d. 2.88 × 104 J to Cal

Step-by-Step Solution:
Step 1 of 3

Solution: The phenomenon of ejection of electrons from the surface of a metal when light of suitable frequency strikes on it, is called photoelectric effect. Step1: a) According to Planck’s quantum theory of radiation, the amount of energy associated with a quantum(in case of light, the quantum of energy is often called photon) of radiation is proportional to the frequency of light, E = h ---(1), where h is a universal constant called Planck’s constant. is the frequency and E is the energy of a photon. Or, E = hc/ -------(2), where, is the wavelength of light and c is the velocity. Step2: Here, given minimum energy required = 6.94 x 10 -19J Planck's constant, h = 6.626 x 10 J.s -34 Substituting the values in equation (1), we get, 6.94 x 10 -19J = (6.626 x 10 J.s) x -19 -34 = (6.94 x 10 J) / (6.626 x 10 J.s) = 1.05 x 10 s . -1 Thus, minimum frequency required to eject an electron is 1.05 x 10 s . 15 -1 Step3: b) From equation (2), = hc/E Here, Velocity of light, c = 3 x 10 m/sec 8 Energy, E = 6.94 x 10 -19J Substituting the values, we get, = [(6.626 x 10 J.s) x (3 x 10 m/sec)] / (6.94 x 10 -19J) -7 = 2.86 x 10 m. Thus, wavelength of the light = 2.86 x 10 m. -7 Step4: c) For each metal a minimum frequency of light called threshold frequency is required below which there is no ejection of electrons...

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##### ISBN: 9780321809247

This textbook survival guide was created for the textbook: Chemistry: A Molecular Approach, edition: 3. The full step-by-step solution to problem: 34E from chapter: 6 was answered by , our top Chemistry solution expert on 02/22/17, 04:35PM. Since the solution to 34E from 6 chapter was answered, more than 622 students have viewed the full step-by-step answer. This full solution covers the following key subjects: light, electrons, Energy, titanium, emit. This expansive textbook survival guide covers 82 chapters, and 9464 solutions. The answer to “Convert between energy units:a. 231 cal to kJb. 132 × 104 kJ to kcalc. 4.99 × 103 kJ to kWhd. 2.88 × 104 J to Cal” is broken down into a number of easy to follow steps, and 26 words. Chemistry: A Molecular Approach was written by and is associated to the ISBN: 9780321809247.

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