A. The radioactive decay equation is N = N0
where T is the
half-life (5730 years), N0 is the number of atoms at time t = 0 and
N is the number at time t.
Rewriting this as:
(N/N0) =
Since N = (1/8) N0 and
substituting known values:
1/8 =
Taking ln of both
sides:
ln(1/8)= -ln(2)*t/5730
t = - 5730 * ln(1/8) /
ln (2)
t = 17,190 years
The tree was cut down 17,190
years ago.
B. N0 = 1,500,000 carbon-14 atoms
Since N = (1/8) N0
N = 187,500 carbon
atoms left
The choices for this problem are bismuth, Bi; platinum, Pt; selenium, Se; calcium, Ca and copper, Cu. I think the correct answer would be selenium. The melting point of bismuth is at a temperature of 544.4 Kelvin. At a temperature of 525 K, it would exist as solid. Platinum melts at 2041.1 K. At 525 K, platinum would be in solid form. Selenium has a melting point at 494 K so that at a temperature of 525 K, it would exist in its liquid state. Calcium has a melting point of 1112 K so it would exist as solid at 525 K. Copper has a melting point at 1358 K, so it would still exist as solid at a temperature of 525 K. Therefore, the answer would only be selenium.
valance electrons that reside in the outermost shell of an atom in the highest energy level. They are important to atoms because the fewer valence electrons that the atom holds, it becomes less stable.
I take honors chemistry I hope this helps.
Answer: I believe C is your best answer
Explanation: The earth revolves around the sun in an elongated circle. Every year is one full “circle.” Due to the earth also having a tilt on its axis, one “side” of the earth is usually closer to the sun. So In the first quarter of the earth’s travel around the sun, it’ll be winter, then the next quarter, spring, followed by Summer halfway through and then Autumn/fall. Such can be compared to how the seasons each usually fill in about a quarter of your calendar. That was explained a bit confusing but I hope I helped, good luck!
Ur cars exhaust tank ur freezer ur toaster ur microwave ur shower