What does Ca(OH)underscore 2 mean? How many atoms is that?
357744
it means there are two of that particular substance present in the compound. Ca is sometimes written as Ca++ when it is by itself to represent that it has 2 positive charges.  (OH) is sometimes written as (OH)- because it has a single negative charge.  for a compound to be electrically neutral you need 2 (OH) to balance 1 Ca.  that means you have 2 Oxygen, 2 Hydrogen and 1 Ca atoms for a total of 5.
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The number after an element is the number of atoms of that element.\n\nStart with NH4\nNH4 has:\n1 nitrogen\n4 hydrogen\n-----\nTotal of 5\n\nBecause it is in parentheses, that means there are multiple molecules of NH4... specifically 2 of them.\nThus (NH4)2 has 10 atoms (5 x 2).\n\nThen you have:\nCr2 --> 2 atoms of cromium\nO7 --> 7 atoms of oxygen\n\nAltogether you have 10 + 2 + 7 = 19 atoms in a molecule of (NH4)2Cr2O7
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Ca(OH)2\nCa needs two more electrons to have a full outer shell, OH needs one electron to have a full valence. So in order to have a ratio of 1:1, you need 2OH.
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mono = 1\ndi = 2\ntri = 3\ntetra = 4\npent = 5\nhex = 6\nhept = 7\noct = 8\nnon = 9\n\nnonmetals:\nif there is no prefix for the first element, it is assumes to be one.\nTHe ening of the anion (the second one listed) is changed to -ide.\n\ncarbon - 1 \noxygen - 2\nCO2  <---The number is a subscript, but you cant do that on here\n\nPhosphorous - 1\nIodine - 3\nPI3\n\nHydrogen - 2\nOxygen - 1  (it should be monoxide)\nH2O\n\nHope that helps you.  Don't feel bad; you can't know what you haven't learned.
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OH- is the hydroxide ion. H2O is water and H3O+ is hydronium ions also known as H+
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1\nThere are 2 Hydrogen atoms, 1 Sulfur atom (as idicated by the absence of any subscript) and 4 Oxygen atoms.
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The total amounts of oxygen atoms equal to six.\n\nHowever, 3 O2 means there are three molecules of diatomic oxygen atoms, and 2 O3 means that there are two molecules of triatomic oxygen atoms.\n\n3 O2 ( "-" shows bonds)\n\nO-O  O-O  O-O = 6 total\n\nO-O-O  O-O-O = 6 total
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Acidic \n\nbelow 6 acidic above 7 basic
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MgC(2)... the 2 is supposed to be subscript.
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H2O2 + OC(NH2)2 -> HCOOH + NH4OH -> NH4(HCOO)
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Calcium phosphate: 13 atoms (3 Ca, 2 P, 8 O)\n4 Aluminum Carbonate molecules: 56 atoms: (36 O, 12 C, 8 Al)\nLead Nitrate: 9 atoms (1 Pb, 2 N, 6 O)\nThe Or threw me off on on this one.  I'm assuming it's Cr.  If it is it would be-\n2 Ammonium Dichromate molecules: 38 atom (4 N, 16 H, 4 Cr, 14 O).\nIf you are adding all the atoms for all the molecules together you get 116 atoms.
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Calcium is the chemical element in the periodic table that has the symbol Ca and atomic number 20. Calcium is a soft grey alkaline earth metal that is used as a reducing agent in the extraction of thorium, zirconium and uranium. Calcium is also the fifth most abundant element in the Earth's crust. It is essential for living organisms, particularly in cell physiology, and is the most common metal in many animals.\n\nIT MAKES YOUR BONES STRONGER - and prevents osteoporosis
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The atomic mass of nitrogen is 14.00674 grams/mole and the atomic mass of calcium is 40.078 grams/mole.  At a level of accuracy of  four significant figures, the masses you have been given correspond to the mass of one mole of each of these elements.  Therefore, there is one mole of nitrogen atoms in 14.01 gms of N and one mole of calcium atoms in 40.08 gms of Ca.\n\nOne mole of atoms  = 6.022 * 10^23 atoms.
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3 hydrogen\n1 phosporus\n4 oxygen\n\ntotal atoms 8\n\nThe subscripts tell you how many atoms of each element are present.  If there is not a subscript after a symbol, you assume there is only one atom of that element.
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Ca2+=[Ar]\nMg2+=[Ne]\nI-=[Xe]\nF-=[Ne]
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The isotopic notation is just the mass number (proton + neutron) before the chemical symbol. Since copper has an atomic number of 29 then the isotopic notation respectively, \n63Cu\n\n65Cu
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1. Make sure that HCl is standardized.\n2. Write the balance equation:\n\nCa(OH)2 + 2HCl ---> CaCl2 + 2H2O\n\n- this means that 1 mole of Ca(OH)2 reacts for every 2 moles of HCl\n\n3. Get the number of moles of HCl reacted by multiplying the volume used to react Ca(OH)2 by the actual concentration of HCl (value from standardization). Divide the result by 2 - and this is now your moles Ca(OH)2.\n\n4. Get the molar solubility of Ca(OH)2 by dividing its number of moles by its volume. Unit is in gram per liter.