If 8cm^3 of h2 reacts with an excess of cl2, calculate how much of the hcl(g) is produced.

First, we need the balanced equation: H₂ + Cl₂ ---> 2HCl

since not much information is given, I am assuming we are at STP and that 22.4 Liters= 1 mol

1) let's convert the volume to moles using the molar volume of a gas. also we need to convert the cm₃ to mL, then to Liters.

8 cm³ (1 ml/ 1 cm³)(1 L/ 1000 mL) (1 mol/ 22.4 Liters)= 3.6x10⁻⁴ moles of H₂

2) let's use the mole ratio of the balanced equation to convert moles of H₂ to moles of HCl

3.6x10⁻⁴ mol H₂ (2 mol HCl/ 1 mol H₂)= 7.1x10⁻⁴ mol HCl

3) lastly, we convert the moles of HCl to grams using the molar mass.

molar mass of HCl= 1.01 + 35.5= 36.51 g/mol

7.1x10⁻⁴ mol HCl (36.51 g/mol)= 0.026 grams HCl

You use the atomic number to find out how many protons and neutrons there are in the atom. you use the atomic mass to find out how many protons and electrons there are in the atom.