Number of molecules in 1 dm³ Oxygen = 2.71 x 10²²
<h3>Further explanation</h3>
Conditions at T 0 ° C and P 1 atm are stated by STP (Standard Temperature and Pressure). At STP, Vm is 22.4 liters/mol.
The mole is the number of particles contained in a substance
1 mol = 6.02.10²³
1 dm³ of oxygen = 1 L Oxygen

n=mol=0.045
No = 6.02.10²³

Answer:
2. Isotope, one of two or more species of atoms of a chemical element with the same atomic number and position in the periodic table and nearly identical chemical behavior but with different atomic masses and physical properties. Every chemical element has one or more isotopes.
3. Since the vast majority of an atom's mass is found its protons and neutrons, subtracting the number of protons (i.e. the atomic number) from the atomic mass will give you the calculated number of neutrons in the atom. In our example, this is: 14 (atomic mass) – 6 (number of protons) = 8 (number of neutrons).
Explanation: Try rewording the questions when looking it up. Hope this helps
1. Ur graph should have 2 vertical lines || , of equal height at mass 13 and 15.
2. One, because you have the mass, which in this case is 13 and the other 15, which has the same height. So it must be the isotope. By definition, an isotope has the same number of protons, but different number of neutrons.
3. to solve for fractional abundance, Let x = fraction of element: "I"-13
then fraction of "I"-15 must be 1-x
so you have: 13x + (15<span>)(1-x) = 13
solve for x.</span>
Answer:
sodium
Explanation:
this is because sodium is neutral ....hence the pH formed will be 7
It has 4 valence electron, all of which are needed to bond with nearest neighbors