Grams To Amu
The molecular mass of water is 2(1) + 16 = 18 amu. The molar mass of water is 18 grams. Molar mass is the mass of a substance that contains Avogadro's number of particles. So: 18 grams of water contains Avogadro's number of water molecules. To find the exact mass of a molecule of water in grams: take the molar mass and divide by Avogadro's number. It so happened that the atomic mass of an element in amu is equal to its molar mass thus, if the molar mass is 880.55 g/mol, each atom is 880.55 amu since there are 6.02 x 10^23 particles in 1 mol.
Formula Weight: sum of masses of all atoms in a given formula or compound
How many grams do 20 atoms of calcium weigh?————————————INTERVIEW1) Revell, K. (November 16, 2016) “An Interview with Heath Giesbrecht, Part. Gram or amu The SI base unit for mass is the kilogram. 1 kilogram is equal to 1000 gram, or 6.949E+26 amu. Note that rounding errors may occur, so always check the results. The atomic mass of H = 1 amu, so you could work out the mass of 1 x H atom in grams as 1/6.02 x 10^23 g = 1.66 x 10^-24g. 4g of He atoms = 1 mole of He atoms = 6.02 x 10^23 atoms. The atomic mass of He = 4 amu, so you could work out the mass of 1 x He atom in grams as 4/6.02 x 10^23 g = 6.64 x 10^-24g (4 times the mass of the each H atom).
Formula Weight = (# atoms of A) (atomic mass of A) + (# atoms of B) (atomic mass B) …
Example: What is the formula weight of glucose: C6H12O6?
Steps to Solve:
1. List each element and the # of atoms of that element are in the formula
Word microsoft office for mac. C: (6 atoms of C)
H: (12 atoms of H)
O: (6 atoms of O)
2. Multiply the number of atoms of each element by that element’s respective mass (from the periodic table) to determine the TOTAL mass contributed to the formula from each element in small “chunks:”
C: (6 atoms of C) x (12 g) = 72 g
H: (12 atoms of H) x (1 g) = 12 g
O: (6 atoms of O) x (16 g) = 96 g
3. Add all accumulated masses for each element in the formula to calculate the formula weight:
72 g + 12 g + 96 g = 180 g
So formula weight of glucose = 180 g
Let’s try one more…
Example: What is the formula weight of aluminum sulfate? Al2(SO4)3 [Ans: 342 g]
Solution:
Al: 2 atoms x 27 g = 54 g
S: 3 atoms x 32 g = 96 g
O: 12 atoms x 16 g = 192 g
54 + 96 g + 192 g = 342g
FYI: Amu and Grams
Grams To Amu
While grams are typically used to calculate formula weight because they are more practice, did you know that the first unit used to denote atomic mass–although now arbitrary—was the atomic mass unit. You may see the “amu” unit used for mass in textbooks, but not to worry, there is no need to convert from one to the other. Luckily, they mean the same thing! So 1 amu = 1 gram.
Grams To Amu Conversion Factor
Dcommander for mac. Why? Every amu is the same as a gram thanks to a clever notion: that 1 amu is equivalent to the 1/12 of the mass of a carbon atom (12 on the periodic table) in amu. So 1/12 x 12=1. That is how we attain the 1:1 ratio.