You will need a periodic table to help you answer this problem. The atomic numbers are arrange from lowest to highest in the periodic table. You can locate element number 55 to be Cesium with an atomic weight of 132.905 amu. So, you start from element 56. The following elements are:
56 Barium 137.328 amu
57 Lanthanium 138.905 amu
58 Cerium 140.116 amu
59 <span>Praseodymium 140.908 amu
60 Neodymium 144.243 amu
Neodymium is already greater than 144 amu. Therefore, these elements only include Barium, Lanthanium, Cerium and Praseodymium.</span>
1. In this reaction, 2 moles of nitrogen gas reacts with 3 moles of oxygen gas to give 2 moles of N2O3 gas. 2 nitrogen molecules react with 3 oxygen molecules to give 2 N2O3 molecules. Under STP, one mole of an ideal gas occupies a volume of 22.4 liters. So in this reaction, 44.8 liters of nitrogen gas reacts with 67.2 liters of oxygen gas to give 44.8 liters of N2O3 gas. The total mass of the reactants (N2 and O2) is the same as the total mass of the product (N2O3). This is called mass balance of a chemical reaction.
2. According to the chemical reaction, 3 moles of chlorine gas produces 2 moles of iron(III) chloride. So, to produce 1 moles of iron(III) chloride, 3/2 (1.5) moles of chlorine gas is required. Therefore, to produce 14 moles of iron(III) chloride, 14 x 1.5 = 21 moles of chlorine is needed.
1 mole = 6.22 x 10^23 molecules (Avogadro's number)
15 moles x (6.22 x 10^23) = 9.33 x 10^24 atoms
117 333.333 m-1 your welco
