Atomic and Molecular Weights
If oxygen is a molecule, then O2 From Avogadro’s constant, Number of molecules,N =moles(n) times Avogadro's constant(L) N=12.10^23 L=6.02.10^23.n=N/L n=12.10^23/12.10^23 n=1.9934 moles Also, moles, n=mass(m)/molar mass(M).mass (m) =moles( n) t. To be realistic, 6.02x 10^23 is avagodros number, which is the number of atoms in 1 mol of a substance.(Oxygen for example) to find this 'molar mass' look for the number just below the atomic symbol on the periodic table, for oxygen, its g/mol or 16g Hope that helped! Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds.After hydrogen and helium, oxygen is the third-most abundant element in the universe by mass. At standard temperature and pressure, two. Oxygen has an atomic mass of 16 gram per mole. The gas oxygen that is in the 'air' has the formula O 2. That means that there are two atoms of oxygen. The formula for carbon dioxide is CO 2, that means one atom of carbon and two atoms of oxygen. 0 2 3 × 1 0 2 3 oxygen atoms = 1 6 g Mass of 1 atom of oxygen = 6. 0 2 3 × 1 0 2 3 1 6 g = 2. 6 6 × 1 0 − 2 3 g Answer verified by Toppr.
The subscripts in chemical formulas, and the coefficients in chemical equations represent exact quantities. (H_2O), for example, indicates that a water molecule comprises exactly two atoms of hydrogen and one atom of oxygen. The following equation:
[ C_3H_{8(g)} + 5O_{2(g)} rightarrow 3CO_{2(g)} + 4H_2O_{(l)} label{Eq1}]
not only tells us that propane reacts with oxygen to produce carbon dioxide and water, but that 1 molecule of propane reacts with 5 molecules of oxygen to produce 3 molecules of carbon dioxide and 4 molecules of water. Since counting individual atoms or molecules is a little difficult, quantitative aspects of chemistry rely on knowing the masses of the compounds involved.
Atoms of different elements have different masses. Early work on the separation of water into its constituent elements (hydrogen and oxygen) indicated that 100 grams of water contained 11.1 grams of hydrogen and 88.9 grams of oxygen:
[text{100 grams Water} rightarrow text{11.1 grams Hydrogen} + text{88.9 grams Oxygen} label{Eq2}]
Later, scientists discovered that water was composed of two atoms of hydrogen for each atom of oxygen. Therefore, in the above analysis, in the 11.1 grams of hydrogen there were twice as many atoms as in the 88.9 grams of oxygen. Therefore, an oxygen atom must weigh about 16 times as much as a hydrogen atom:
Mass Of One Atom Of Oxygen Is
[ dfrac{dfrac{88.9;g;Oxygen}{1; atom}}{dfrac{111;g;Hydrogen}{2;atoms}} = 16 label{Eq3}]
Hydrogen, the lightest element, was assigned a relative mass of '1', and the other elements were assigned 'atomic masses' relative to this value for hydrogen. Thus, oxygen was assigned an atomic mass of 16. We now know that a hydrogen atom has a mass of 1.6735 x 10-24 grams, and that the oxygen atom has a mass of 2.6561 X 10-23 grams. As we saw earlier, it is convenient to use a reference unit when dealing with such small numbers: the atomic mass unit. The atomic mass unit (amu) was not standardized against hydrogen, but rather, against the 12C isotope of carbon (amu = 12).
Thus, the mass of the hydrogen atom (1H) is 1.0080 amu, and the mass of an oxygen atom (16O) is 15.995 amu. Once the masses of atoms were determined, the amu could be assigned an actual value:
1 amu = 1.66054 x 10Is Oxygen A Atom
-24gramsMass Of One Atom Of Oxygen Is Class 9
Mass Of One Atom Of Oxygen Is Known
gram = 6.02214 x 1023Mass Of One Atom Of Oxygen Is
amu