Answer:
W = -10.3 kJ
Explanation:
During combustion, the system performs work and releases heat. Therefore, the change in internal energy is negative, and the change in enthalpy, which is equal to heat at constant pressure, is also negative. Work is then calculated by rearranging the equation for the change in internal energy:
w=ΔE−qp=−5084.3 kJ−(−5074.0 kJ)
The release of heat is much greater than the work performed by the system on its surroundings. The potential energy stored in the bonds of octane explains why considerably large amounts of energy can be lost by the system during combustion.
First, we will get the "n", the number of half lives, it is the elapsed time over the half life. In the problem, the time is measured in days, so we have
6/2 = 3
to get the ending amount of radioactive sample, we have
32g x (1/2)³ = 4 grams of radioactive sample ⇒ the amount left after 6 days
<em>Advantages</em>
Chemistry helps you to understand the world around you.
Basic knowledge of chemistry helps you to read and understand product labels.
Chemistry can help you make informed decisions.
Chemistry is at the heart of cooking.
A command of chemistry can help keep you safe!
<em>Disadvantages</em><em> </em>
It isn't a sustainable form of energy.
It can be expensive.
Some forms of chemical energy are quite rare.
It can produce harmful waste.
It can be used to create devastating weapons.
It offers short-term benefits for long-term consequences.
Tan2(∅) ≡ 2tan(∅) / (1 - tan²∅)
Thus,
2tan(∅) / (1 - tan²(∅)) + tan(∅) = 0
2tan(∅) / (1 - tan²(∅)) = -tan(∅)
1 - tan²(∅) = -2
tan²(∅) = 3
∅ = tan⁻¹(√3)
∅ = 4nπ/3
<span>C. Static electricity. Except that electrons are never really at rest.</span>
