When atoms and molecules speed up or slow down, that is a physical change. When they change state from liquid to solid or from gas to liquid, that is a physical change. ... The ions or molecules can still come back together to form the original substance
Given, half life of a certain radioactive element = 800 years.
Amount of substance remaining at time t = 12.5%
Lets consider the initial amount of the radioactive substance = 100%
Using the half life equation:
A = A₀(1/2)^t/t₁/₂
where A₀ is the amount of radioactive substance at time zero and A is the amount of radioactive substance at time t, and t₁/₂ is the half-life of the radioactive substance.
Plugging the given data into the half life equation we have,
12.5 = 100 . (1/2)^t/800
12.5/100 = (1/2)^t/800
0.125 = (0.5)^t/800
(0.5)^3 = (0.5)^t/800
3 = t/800
t = 2400 years
Thus the object is 2400 years old.
Hi! My answer would be D, USA.
Explanation:
We are provided with 5 pieces of an address. They are as followed.
12 Riverdale Lane, Apartment A, San Jose, California, and USA.
Imagine each of the five parts of Beck's address represents Earth, the Milky Way, the moon, the solar system, or the universe, based on their sizes. Which of the following parts of Beck's address would represent the solar system?
If we have to plug in Earth, the Milky Way, the moon, the solar system, and the universe, (all based on size,) we would first start with what "Apartment A" would be in this scenario. Apartment A is the smallest piece we have to work with, and so is the moon. This leads me to believe that the Moon should be plugged into Apartment A. Now, 12 Riverdale Lane is most likely going to be the Earth, since it is the second smallest one on our list. San Jose would turn into the Sun, California represents the Milky Way, and USA represents the solar system.
I sincerely hope I helped!
Have a wonderful day :)
~AmbitiousAndProud
Answer:
A and F i think
Explanation:
Freezing point depression is a colligative property observed in solutions that results from the introduction of solute molecules to a solvent. The freezing points of solutions are all lower than that of the pure solvent and is directly proportional to the molality of the solute
