It is commonly known that our Galaxy rotates upon the sun because of gravity. The diagrams' arrows sort of describe it. Id suggest Gravity as the answer.
Answer:
A. Producing certain synthetic materials could have a greater environmental impact than disposing of them.
Explanation
I just did this question and got it right.
Answer:
Option D = 0.2 Kj
Explanation:
Given data:
Mass of diethyl ether = 1.0 g
Hvap = 15.7 Kj / mol
Heat absorbed = ?
Solution:
Q = mass × Hvap / molar mass
Q = 1.0 g × 15.7 Kj / mol / 74.12 g/mol
Q = 15.7 Kj / 74.12
Q = 0.212 KJ
Answer:
0.0468 g.
Explanation:
- The decay of radioactive elements obeys first-order kinetics.
- For a first-order reaction: k = ln2/(t1/2) = 0.693/(t1/2).
Where, k is the rate constant of the reaction.
t1/2 is the half-life time of the reaction (t1/2 = 1620 years).
∴ k = ln2/(t1/2) = 0.693/(1620 years) = 4.28 x 10⁻⁴ year⁻¹.
- For first-order reaction: <em>kt = lna/(a-x).</em>
where, k is the rate constant of the reaction (k = 4.28 x 10⁻⁴ year⁻¹).
t is the time of the reaction (t = t1/2 x 8 = 1620 years x 8 = 12960 year).
a is the initial concentration (a = 12.0 g).
(a-x) is the remaining concentration.
∴ kt = lna/(a-x)
(4.28 x 10⁻⁴ year⁻¹)(12960 year) = ln(12)/(a-x).
5.54688 = ln(12)/(a-x).
Taking e for the both sides:
256.34 = (12)/(a-x).
<em>∴ (a-x) = 12/256.34 = 0.0468 g.</em>
