H 1 Hydrogen 1.00794 | Periodic Table | He 2 Helium 4.002602 | |||||||||||||||

Li 3 Lithium 6.941 | Be 4 Beryllium 9.012182 | of the Elements | B 5 Boron 10.811 | C 6 Carbon 12.0107 | N 7 Nitrogen 14.0067 | O 8 Oxygen 15.9994 | F 9 Fluorine 18.9984032 | Ne 10 Neon 20.1797 | |||||||||

Na 11 Sodium 22.98976... | Mg 12 Magnesium 24.305 | mouse/touch for more information | Al 13 Aluminum 26.9815386 | Si 14 Silicon 28.0855 | P 15 Phosphorus 30.973762 | S 16 Sulfur 32.065 | Cl 17 Chlorine 35.453 | Ar 18 Argon 39.948 | |||||||||

K 19 Potassium 39.948 | Ca 20 Calcium 40.078 | Sc 21 Scandium 44.955912 | Ti 22 Titanium 47.867 | V 23 Vanadium 50.9415 | Cr 24 Chromium 51.9961 | Mn 25 Manganese 54.938045 | Fe 26 Iron 55.845 | Co 27 Cobalt 58.933195 | Ni 28 Nickel 58.6934 | Cu 29 Copper 63.546 | Zn 30 Zinc 65.38 | Ga 31 Gallium 69.723 | Ge 32 Germanium 72.63 | As 33 Arsenic 74.9216 | Se 34 Selenium 78.96 | Br 35 Bromine 79.904 | Kr 36 Krypton 83.798 |

Rb 37 Rubidium 85.4678 | Sr 38 Strontium 87.62 | Y 39 Yttrium 88.90585 | Zr 40 Zirconium 91.224 | Nb 41 Niobium 92.90628 | Mo 42 Molybdenum 95.96 | Tc 43 Technetium (98) | Ru 44 Ruthenium 101.07 | Rh 45 Rhodium 102.9055 | Pd 46 Palladium 106.42 | Ag 47 Silver 107.8682 | Cd 48 Cadmium 112.411 | In 49 Indium 114.818 | Sn 50 Tin 118.71 | Sb 51 Antimony 121.76 | Te 52 Tellurium 127.6 | I 53 Iodine 126.90447 | Xe 54 Xenon 131.293 |

Cs 55 Caesium 132.9054 | Ba 56 Barium 132.9054 | Hf 72 Hafnium 178.49 | Ta 73 Tantalum 180.94788 | W 74 Tungsten 183.84 | Re 75 Rhenium 186.207 | Os 76 Osmium 190.23 | Ir 77 Iridium 192.217 | Pt 78 Platinum 195.084 | Au 79 Gold 196.966569 | Hg 80 Mercury 200.59 | Ti 81 Thallium 204.3833 | Pb 82 Lead 207.2 | Bi 83 Bismuth 208.9804 | Po 84 Polonium (209) | At 85 Astatine (210) | Rn 86 Radon (222) | |

Fr 87 Francium (223) | Ra 88 Radium (226) | Rf 104 Rutherfordium (267) | Db 105 Dubnium (268) | Sg 106 Seaborgium (271) | Bh 107 Bohrium (272) | Hs 108 Hassium (270) | Mt 109 Meitnerium (276) | Ds 110 Darmstadium (281) | Rg 111 Roentgenium (280) | Cn 112 Copernicium (285) | Uut 113 Unutrium (284) | Uuq 114 Flerovium (289) | UuP 115 Ununpentium (288) | Lv 116 Livermorium (293) | Uus 117 Ununseptium (294) | Uuo 118 Ununoctium (294) | |

La 57 Lanthanum 138.90547 | Ce 58 Cerium 140.116 | Pr 59 Praseodymium 140.90765 | Nd 60 Neodymium 144.242 | Pm 61 Promethium (145) | Sm 62 Samarium 150.36 | Eu 63 Europium 151.964 | Gd 64 Gadolinium 157.25 | Tb 65 Terbium 158.92535 | Dy 66 Dysprosium 162.5 | Ho 67 Holmium 164.93032 | Er 68 Erbium 167.259 | Tm 69 Thulium 168.93421 | Yb 70 Ytterbium 173.054 | Lu 71 Lutetium 174.9668 | |||

Ac 89 Actinium (227) | Th 90 Thorium 232.03806 | Pa 91 Protactinium 231.0588 | U 92 Uranium 238.02891 | Np 93 Neptunium (237) | Pu 94 Plutonium (244) | Am 95 Americium (243) | Cm 96 Curium (247) | Bk 97 Berkelium (247) | Cf 98 Californium (251) | Es 99 Einstenium (252) | Fm 100 Fermium (257) | Md 101 Mendelevium (258) | No 102 Nobelium (259) | Lr 103 Lawrencium (262) |

Converting atoms to grams is an essential process in basic chemistry and forms the foundation for the more difficult calculations used in more advanced chemistry. The conversion requires a fundamental understanding of Avogadroâ€™s Number, atomic weights, dimensional analysis and the definition of a mole of a substance. Using these items, if you know how many atoms of a substance you are dealing with, you can easily convert this to grams using the following process.

## Instructions

For the purpose of this demonstration we will assume that we are working with 14 atoms of carbon. Write â€œ14 atoms Câ€ on the top left of your scratch paper.

Avogadroâ€™s number (6.02 x 10^23) is the number of particles of a substance in one mole (mol) of that substance. There are 6.02 x 10^23 atoms of carbon in a mole of carbon and 6.02 x 10^23 molecules of water in a mole of water. Because you are using dimensional analysis to cancel out â€œatoms,â€ to the right of what you wrote in Step 1 write as a fraction, â€œ1 mol C / 6.02 x 10^23 atomsâ€ and prepare to multiply across, such that your equation looks like this so far:

14 atoms C 1 mol x ------------------------------- 6.02 x 10^23 atoms C

Refer to the periodic table of elements and find the atomic weight for the substance you are working with, rounding to the appropriate number of significant digits. In this case, carbon has an atomic weight of 12.0 atomic mass units (amu). The molar mass (in grams) of any substance is always numerically equal to its formula weight (in amu), so for carbon, there are 12.0 grams (g) in one mole of carbon. Write this as a fraction to the right of Step 2, again multiplying. Also, put an equal sign to the far right. It should look like this:

14 atoms C 1 mol 12.0 g C x ------------------------------ x -------------- = 6.02 x 10^23 atoms C 1 mol C

Because the units in fractions get treated the same as numbers do, the â€œatoms Câ€ from Steps 1 and 2 cancel each other out and the â€œmol Câ€ from Steps 2 and 3 cancel out, leaving you with grams (g) as the unit of measurement your answer will be in. This is a good way to check your work.

Multiply across the top to get 168 g C and across the bottom to get 6.02 x 10^23.

Divide the top by the bottom, minding significant figures, to get 2.8 x 10^22 grams of carbon in 14 atoms of carbon.

#### Tip

Once you have done this a few times, you will see that multiplying the number of atoms and dividing the result by Avogadroâ€™s number (6.02 x 10^23) will suffice.

#### Warning

Use only as many significant figures as the least precise number in your calculation. In this example, 14 is two significant figures, so our answer is to two figures as well.