Answer
Calculating the mass number for an atom requires that we know the atomic number and the number of protons in the atom’s nucleus. The mass number then gives us the average weight of atoms of a given element. However, as long as the number of protons equals the number of neutrons, the values balance out and we always obtain a whole number for the mass number.
Explanation:
those 3
The reaction is,
H2S + I2 --------------> 2 HI +S
Molar weight of H2S = 34 g per mol
Molar weight of HI =128 g per mol
Molar weight of I2 =254 g per mol
Moles of H2S in 49.2 g = 49.2 /34 mol = 1.447 mol
So according to stoichiometry of the reaction, number of I2 mols needed
= 1.447 mol
The mass of I2 needed = 1.447 mol x 254 g
The balanced equation for the neutralisation reaction is as follows
2HNO₃ + Ba(OH)₂ ---> Ba(NO₃)₂ + 2H₂O
stoichiometry of HNO₃ to Ba(OH)₂ is 2:1
number of Ba(OH)₂ mol present - 0.108 mol
1 mol of Ba(OH)₂ neutralises 2 mol of Ba(OH)₂
therefore 0.108 mol of Ba(OH)₂ neutralises - 2 x 0.108 mol = 0.216 mol of HNO₃
When you wake up early, and go brush your teeth the toothpaste is made of chemical compounds, the water that you use to wash your faceis treated chemically. To make the coffee sugar or sweetener has chemical compounds.
hope this helps!
