Carbon-14 and Uranium-238 have something we call a half live, which is basically a known time period for it to change half of its C-14 or U-238 radioactively decay. Since we know how long that is 5730 years for Carbon-14 for half a sample to deteriorate, than we can figure out how old it is.
Answer:
4.13×10²⁷ molecules of N₂ are in the room
Explanation:
ideal gases Law → P . V = n . R . T
Pressure . volume = moles . Ideal Gases Constant . T° K
T°K = T°C + 273 → 20°C + 273 = 293K
Let's determine the volume of the room:
18 ft . 18 ft . 18ft = 5832 ft³
We convert the ft³ to L → 5832 ft³ . 28.3L / 1 ft³ = 165045.6 L
1 atm . 165045.6 L = n . 0.082 L.atm/mol.K . 293K
(1 atm . 165045.6 L) / 0.082 L.atm/mol.K . 293K = n
6869.4 moles of N₂ are in the room
If we want to find out the number of molecules we multiply the moles by NA
6869.4 mol . 6.02×10²³ = 4.13×10²⁷ molecules
Cathode Ray experiment to figure out electrons exist -> atoms can be broken up into subatomic particles
An anion has a negative charge, while a cation has a positive charge.
I would say D, because you need to start with nothing to measure the different sizes as they start to grow. hope this helps!
