18 gram water means 1 mole H2O. There are 2 hydrogen atoms and 1 oxygen atom in H2O. There are 3 atoms in water, 1 oxygen, 2 hydrogen. total molecular weight 18. (assuming all average isotopic weight). 20g/18MU x 6E23 = 6. 6E23 molecules. Thus, there are 3. 35 * 10^22 molecules of water in 1 gram. Now, each molecule of water has 2 hydrogen atoms and 1 oxygen atom. This means that there are 3 atoms in each molecule. So, 2 moles of water (36 grams) contain "2 x 2 x 6 x 10^23 = 2. 4 x 10^24 atoms of hydrogen.
A mass in grams numerically equal to the molecular weight contains one mole of molecules, which is known to be 6. 02 x 10^23 (Avogadro's number). So if you have x grams of a substance, and the molecular weight is y, then the number of moles n = x/y and the number of molecules = n multiplied by Avogadro's number.
If we have one mole of water, then we know that it will have a mass of 2 grams (for 2 moles of H atoms) + 16 grams (for one mole O atom) = 18 grams.
For H2O, there is one atom of oxygen and two atoms of hydrogen.
You can view more details on each measurement unit: molecular weight of O2 or grams The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles O2, or 31. 9988 grams.
One sulfuric (H2SO4) molecule has 2 hydrogen atoms, 1 sulfur atom, and 4 oxygen atoms. You can also say one mole of sulfuric acid has two mols of hydrogen atoms, 1 mol of sulfur atoms, and 4 moles of oxygen atoms.
In summary, for a typical human of 70 kg, there are almost 7*1027 atoms (that's a 7 followed by 27 zeros! ) Another way of saying this is "seven billion billion billion. " Of this, almost 2/3 is hydrogen, 1/4 is oxygen, and about 1/10 is carbon. These three atoms add up to 99% of the total!
Nitrogen atoms have seven electrons and 7 protons with five electrons in the outer shell.
Assuming the Water is pure, 10g of water contains approximately 3. 33*10^23 water molecules (via conversion to moles of water, and multiplying it by Avagadro's number), multiply this by another 3 (since every water molecule contains 3 atoms, 2 hydrogen and 1 oxygen), leaving us with 10^24 atoms in total.
Avogadro's number is a very important relationship to remember: 1 mole = 6. 022×1023 6. 022 × 10 23 atoms, molecules, protons, etc. To convert from moles to atoms, multiply the molar amount by Avogadro's number. To convert from atoms to moles, divide the atom amount by Avogadro's number (or multiply by its reciprocal).