Answer:
The gas that Dr. Brightguy added was O₂
Explanation:
Ideal Gases Law to solve this:
P . V = n . R . T
Firstly, let's convert 736 Torr in atm
736 Torr is atmospheric pressure = 1 atm
20°C = 273 + 20 = 293 T°K
125 mL = 0.125L
0.125 L . 1 atm = n . 0.082 L.atm / mol.K . 293K
(0.125L .1atm) / (0.082 mol.K /L.atm . 293K) = n
5.20x10⁻³ mol = n
mass / mol = molar mass
0.1727 g / 5.20x10⁻³ mol = 33.2 g/m
This molar mass corresponds nearly to O₂
There are some standard numbers that help us describe the structure of an atom and help us categorize them. Those are the atomic number, the mass number and the numbers of electrons in an atom (or ion). Atoms are electrically neutral, hence they have the same number of protons as electrons. If an atom has a charge and has thus become an ion, it is because electrons joined it or left. For example in this case, since the ion has +2 charge, 2 electrons left it and thus the ion has 4 electrons (2 electrons less than its protons). The mass number is the sum of the protons and neutrons of an atom (that are in the nucleus). In this case, this yields a mass number of 13 for this ion. The atomic number of an atom (or ion) is the total number of protons in the nucleus. Protons do not leave the nucleus except for radioactive reactions and thus the atomic number of an atom (or ion) does not change in chemical reactions. In this case, the ion has an atomic number of 6.
Answer:
An isotope is one of two or more forms of the same chemical element. Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number, but a different number of neutrons giving each elemental isotope a different atomic weight.
