The mass of 60.4% of the atoms of an element is 68.9257 amu.?
109271
This is from Mr. Jeffy:\n\nIf you know that 60.4% of the naturally occuring isotopes have an atomic mass of 68.9257 amu, then you know that the other 39.6% much have an atomic mass such that the averge is 70.9249 amu.\nSo,\n(60.4% of 68.9257) + (39.6% of x) = 70.9249\nSo solve for x.\n============================================================\n\nI think he merely switched a couple of terms here, so I think the equation will look like this:\n\n(60.4% of 68.9257) + (39.6% of 70.9249) = x\n\nSolving:\n\n41.6311228 + 28.0862064 = (approx.) 69.72\n\nYou have gallium (Ga), my friend.
213411
Atomic Number 3\nhttp://www.jergym.hiedu.cz/~canovm/vyhledav/varianty/litva.gif
874922
500 atoms Fe*( 1mol Fe/6,022*10^23 atoms Fe)(55,847 g Fe/ 1mol Fe)=\n4,64*10^-20g of Fe atoms
384517
(12/12+16)*100=42.85\n12---------atomic mass of carbon\n16---------atomic mass of oxygen
482317
Atomic wt of Al is 13,Cu is 29,Zn is 30 and Fe is 26.So less atomic wt,Al contains more number of atoms in 50gm
73838
Its' probably a rounding error. It would depend on which masses for the elements you use, how precise you want to be.
730167
Very close to the mass of a proton.  It is about 1.6749 x 10^-27 kg, 1 u, or 939.57 MeV/c^2.
977036
Na: atomic mass 23\nCl: atomic mass 35\nNaCl: atomic mass 23 + 35 = 58\n\n(50 g) / (58 (g / mole)) = 0.862068966 moles\n\n(0.862068966 moles) / (2.5 L) = 0.344827586 moles/L
702947
The atomic weight is the mass in grams per mole (atomic mass of iron = 55.845).\n\nA mole is 6.02 x 10^23 atoms, therefore the mass of 500 atoms would be:\n\n500/(6.02x10^23) x 55.845 = 4.64 x 10^-20 grams.\n\nNotice that's 10 to the -20 power.
72779
A molecule is made up of atoms.
967003
the number of milliequivalents (mEq), or the number of millimoles (mmol)\nCalcium has a molecular weight of 40.08 grams/mole\nCalcium has a valence of +2\nThe equivalent weight = (40.08grams/mole)/(2 equivalents/mole) = 20.04 grams/eq\nso the weight is 80.16g
365764
Your second statement is correct, i.e proton mass+electron mass = constant mass and energy.\nok, This is with reference with another question you asked about mass defect(and chose my answer as the best, thanks). The sum of individual masses is greater than the actual mass of the atom. I am sure of this because this is what explains the stability of an atom(less energy, more stable).\nI'll give you an example which I took from my chem book\n\nMe = 0.0005486 amu(atomic mass unit)\nMp = 1.007277 amu\nMn = 1.008665 amu\nMe,Mp,Mn are masses of electron, proton and neutron respectively and 1 amu = 1.6605 x 10^-27 Kg\n\nOne He atom contains two electrons, two protons and two neutrons.\nSumming up the values of the constituents you get 4.032981amu as the expected mass of the atom.\nHowever the actual mass of the atom is 4.002603amu\nDifference = 0.030378 amu\n\nThe formula to find the binding evergy(energy required to bring the constituents together) is: mass defect x 931.48MeV\n\nHere that would be 0.030378 x 931.48 = 28.296 MeV\ni.e that is the equivalent of the mass defect in energy.\nThe '931.48' part is calculated using Einstein's formula E=mc^2.
829932
Take radium and subtract two from its atomic number. Then find the element with that result as its atomic number. I'm too lazy to see what that is right now.
1001801
The atomic number for plutonium is 94.  The weighted average value for the atomic mass of plutonium is 244.0642 grams/mole.
33642
Use the periodic table to find the atomic mass of the element and subtract from this the atomic number.  \n\nThe atomic mass is equal to sum of proton and neutrons, and the atomic number is the number of protons an atom has.  Electrons have such a small mass that they don't really have any noticable effect on the atomic mass.\n\nEx: Oxygen (atomic mass - 16, atomic number - 8)\n\n16 - 8 = 8, therefore the number of protons is equal to 8
308860
The molecular weight of acetaldehyde is 44.053 amu.  A good site to go to for questions about simple organic molecules is http://www.chemfinder.com.\n\nThe person below me used only whole numbers for the masses of the atoms.  Carbon doesn't weight 12 amu, it weighs 12.011 amu and Hydrogen weighs 1.008 amu.
1138448
Look on a periodic table.\n\nIt should be listed below the atomic number as a decimal value.  The mass number is an average mass (in atomic mass units) of an element, based on different isotopes.  It equals the number of protons + the number of neutrons in the nucleus.