The thermite reaction, Fe$_2$O$_3$(s) + 2 Al(s) $\longrightarrow$ 2 Fe(s) + Al$_2$O$_3$(s), is one of the most exothermic reactions known. The heat released is sufficient to melt the iron product; consequently, the thermite reaction is used to weld metal under the ocean. $\Delta H^{\circ}$ for the thermite reaction is -851.5 kJ/mole. What is the mass change per mole of Fe$_2$O$_3$ that accompanies this reaction?

keyboard and mouse are examples of

Which of the following is not an example of system software?

a. Microsoft Windows 10

b. Java compilers

c. Mac OS X

d. Microsoft Excel

e. All of the above

The half-life for the process $^{238} \mathrm { U } \longrightarrow ^{206} \mathrm { Pb }$ is $4.5 \times 10 ^ { 9 } yr$ A mineral sample contains 75.0 mg of $^{238}U$ and 18.0 mg of $^{206}Pb.$ What is the age of the mineral?

Potassium-40 decays to argon-40 with a half-life of $1.27 \times 10 ^ { 9 }$ yr. What is the age of a rock in which the mass ratio of $^{40}Ar$ to $^{40}K$ is 4.2?

A wooden artifact from a Chinese temple has a $^{14}C$ activity of 38.0 counts per minute as compared with an activity of 58.2 counts per minute for a standard of zero age. From the half-life for $^{14}C$ decay, 5715 yr, determine the age of the artifact.

The cloth shroud from around a mummy is found to have a $^{14}C$ activity of 9.7 disintegrations per minute per gram of carbon as compared with living organisms that undergo 16.3 disintegrations per minute per gram of ca rbon. From the half-life for $^{14}C$ decay, 5715 yr, calculate the age of the shroud.

Which of the following is an example of Rapid Application Development?

• A. Agile methodology
• B. Prototyping
• C. Rapid system development
• D. Software system

Cobalt-60, which undergoes beta decay, has a half- life of 5.26 yr. What is the activity of the sample in Bq?

Which of the following statements does not reflect position-based leadership?

A) Leaders should be able to count on loyalty from their subordinates.

B) Leaders are risk-takers.

C) Leaders should discuss options with subordinates.

D) A leader should take charge

Which of the following is not a common indoor air pollutant? (a) Asbestos, (b) Carbon monoxide, (c) Ozone, (d) Radon.

Cobalt-60, which undergoes beta decay, has a half-life of 5.26 yr. How many beta particles are emitted in 600 s by a 3.75-mg sample of

$$^{60}Co?$$

Radium-226, which undergoes alpha decay, has a half-life of 1600 yr. What is the activity of the sample in mCi?

Mercury poisoning is a debilitating disease that is often fatal. In the human body, Mercury reacts with esstenial enzymes leading to irreversible inactivity of these enzymes. If the amount of mercury in a polluted lake is 0.4 ug Hg/mL, what is the total mass in kilograms of mercury in the lake? (The lake has a surface area of 100mi^2 and an average depth of 20ft.