Molecular Mass

450 moles of C2H4 contain 10.815,43 g carbon.

2 x Avogadro's number. It should be noted that 2 moles of VW Beetles would have a mass over 250 times greater than that of the entire Earth.

342.3 g mol-1

6,1x10-3 moles of carbon 36,7350592277.1020 atoms.

10,0 moles of bromine atoms contain 60,22140857.1023 atoms.
Attention: valid for bromine atoms !.

H2O: 44g x 1 mol/18 g = 2.44 moles and 2.44 moles x 6.02x10^23 atoms/mole = 1.5x10^24 atoms
S-32: 44g x 1mol/32g = 1.375 moles and 1.375 moles x 6.02x10^23 atoms/mole = 8.3x1^23 atoms
O-16: 44g x 1 mol/16g = 0.6875 moles and 0.6875 moles x 6.02x10^23 atoms/mol = 4.2x10^23 atoms
H-1: 44g x 1mol/1g = 44 moles and 44 moles x 6.02x10^23 atoms/mole = 2.6x10^25 atoms

You think probably to Amedeo Avogadro.

0,667 g oxygen equal 0,021 moles.

2

C12H24O12 is the chemical formula of lactose monohydrate. The answer is 0,12 moles.

5,7 moles (SO4)3-.

The number of moles is 2,997.

The answer is 12, 044 280.1023 atoms.

Higher the concentration of the solute, lower is the freezing point.

Sodium nitrate is NaNO3. The percent nitrate is given by :

PCT Nitrate = [ ( 14 + 48 ) / ( 23 + 14 + 48 ) ][ 100 ] = [ 62 /85 ][ 100 ] = 72.94 mass percent <----

2,50 moles of silicon contain 15,055352142.10e23 atoms.

This is very easy. you need 9.752l for that.

There are three variables in gas work that go into volume: amount of gas, pressure of gas, temperature of gas. If we double the amount of gas - the moles - and maintain the temperature and pressure, the volume must double.

471,6 g of anhydrous Ba(OH)2 is equivalent to 2,75 moles.

The number of molecules is 12,044280.10e23.

The answer is 64,9 moles.

The answer is 0,0625 mol.

This is carbon tetra chloride. there are 0.3636 moles in this mass.

55.0 moles of sodium are equal to 1 264,44 g.

In order to find how many Moles of He are 1.20 x 1025 atoms of He, you need to divide 1.20 x 1025 atoms by the Avagadro's number (6.022 x 1023) The answer is 19.9 moles of He.