Assignment for Crackcode only

Ivy Bucsa

PSY-102

September 7,2014

Lillian Flakes

Assignments Chapter 12 and 13

Chapter 12

47. If an atom has 43 electrons, 56 neutrons, and 43 protons,

what is its approximate atomic mass? What is the name

of this element?

52. Which contributes more to an atom’s mass: electrons or

protons? Which contributes more to an atom’s size?

53. What is the approximate mass of an oxygen atom in

atomic mass units? What is the approximate mass of two

oxygen atoms? How about an oxygen molecule?

66. With scanning probe microscopy technology, we see not

actual atoms but rather images of them. Explain.

67. Why isn’t it possible for a scanning probe microscope to

make images of the inside of an atom?

Readiness Test

4. If an atom has 43 electrons, 56 neutrons, and 43 protons,

what is its approximate atomic mass? What is the name

of this element?

(a) 137 amu; barium

(b) 99 amu; technetium

(c) 99 amu; radon

(d) 142 amu; einsteinium

Chapter 13

Think and Solve 3030. Consider a radioactive sample with a half-life of one week.

How much of the original sample will be left at the end of

the second week? The third week? The fourth week?

Exercises

43. What are the atomic number and the atomic mass of the

element formed when 84

218Po emits a beta particle? What

are they if the polonium emits an alpha particle?

48. Is carbon dating advisable for measuring the age of materials

a few years old? How about a few thousand years

old? A few million years old?

50. The age of the Dead Sea Scrolls was determined by carbon-

14 dating. Could this technique have worked if they

had been carved on stone tablets? Explain

54. Why will nuclear fission probably never be used directly for

powering automobiles? How could it be used indirectly?

Discussion Questions

74. Your friend Paul says that the helium used to inflate

balloons is a product of radioactive decay. Your mutual

friend Steve says no way. Then there’s your friend Alison,

fretful about living near a fission power plant. She

wishes to get away from radiation by traveling to the high

mountains and sleeping out at night on granite outcroppings.

Still another friend, Michele, has journeyed to the

mountain foothills to escape the effects of radioactivity

altogether. While bathing in the warmth of a natural hot

spring, she wonders aloud how the spring gets its heat.

What do you tell these friends?

Readiness Test

6. A certain radioactive element has a half-life of 1 h. If you

start with a 1-g sample of the element at noon, how much

of this same element will be left at 3:00 PM?

(a) 0.5 g

(b) 0.25 g

(c) 0.125 g

(d) 0.0625

7. The isotope cesium-137, which has a half-life of 30 years,

is a product of nuclear power plants. How long will it

take for this isotope to decay to about one-half of its

original amount?

(a) 0 years

(b) 15 years

(c) 30 years

(d) 60 years

(e) 90 years