how many hydrogen atoms are present in 3 millimoles of water?

Question

the answer is 3.61 10^21. but i want to know how to find it, how do i show the work? thanks!

Answer 1

In the formulae (II), (IV), and (V), R and R.sup.1 respectively represent, independently from each other, a member selected from the group consisting of a hydrogen atom and organic radicals, for example, hydrocarbon radicals having 1 to 6 carbon atoms and alkoxyl radicals having 1 to 6 carbon atoms. The hydrocarbon radicals include alkyl, alkylene, and aryl radicals. The preferred hydrocarbon radicals are methyl, ethyl, and propyl radicals.

The aromatic imide polymer of the present invention is prepared by the polymerization and imidization of an acid component consisting of at least one aromatic tetracarboxylic acid or its derivative, for example, dianhydride, acid chloride, ester, or salt, with an amine component consisting of at least one aromatic diamine in an approximately equal molar amount to that of the acid component, in accordance with any conventional method.

The aromatic tetracarboxylic acid usable for the preparation of the aromatic imide polymer of the present invention is preferably selected from biphenyl tetracarboxylic acids, for example, 3,3',4,4'-biphenyl tetracarboxylic acid, and 2,3,3',4'-biphenyl tetracarboxylic acid; benzophenone tetracarboxylic acids, for example, 3,3',4,4'-benzophenone tetracarboxylic acid and 2,3,3'4'-benzophenone tetracarboxylic acid; pyromellitic acid; and dianhydrides and lower alcohol esters of the above-mentioned tetracarboxylic acids.

It is preferable that the acid component contain 50 to 100 molar % of at least one biphenyl tetracarboxylic acid compound, because it is effective for obtaining an aromatic imide polymer which exhibits a high solubility in organic solvents such as phenolic compounds and, therefore, which is easily converted to a stable dope solution useful for the preparation of an aromatic imide polymer gas separating layer.

The amine component for the aromatic imide polymer of the present invention contains 20 to 100 molar %, preferably 40 to 100 molar %, of at least one diaminodiphenylene compound containing sulfur of the formula (VI): ##STR10## and 0 to 80 molar % preferably 0 to 60 molar %, of at least one other aromatic diamine compound of the formula

Answer 2

1 mole of water contains Avogadro's number of water molecules. Each water molecule contains two hydrogen atoms. Therefore 1 mole of water contains 2*6.022*10^23 hydrogen atoms. A miilimole is 10^-3 mole, so 3 miilimoles of water contains

3*2*6.022*10^20

36.1*10^20 = 36.1*10^21 hydrogen atoms

Answer 3

A mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram (or 12 grams) of carbon-12, where the carbon-12 atoms are unbound, at rest and in their ground state.[1] The number of atoms in 0.012 kilogram of carbon-12 is known as Avogadro's number, and is determined empirically. The currently accepted value is 6.0221415(10)×1023 mol-1 (2002 CODATA).
When the mole is used to specify the amount of a substance, the kind of elementary entities (particles) in the substance must be identified. The particles can be atoms, molecules, ions, formula units, electrons, or other particles. For example, one mole of water is equivalent to about 18 grams of water and contains one mole of H2O molecules, but three moles of atoms (two moles H and one mole O).

Answer 4

Count them , remembering to arrange them into fives .