Chemistry question

Question

Chlorine can be prepared in the laboratory by the reaction of manganese dioxide with hydrochloric acid, , as described by the chemical equation

How much  should be added to excess  to obtain  at 25 °C and ?

mass of MnO2 = ____g

Answer 1

MnO₂(s) + 4HCl(aq) ==> MnCl₂(aq) + 2H₂O(l) + Cl₂(g)

Find the moles of Cl₂ that is produced:

PV = nRT (Ideal Gas Law) and solving for moles (n), we have..

n = PV/RT = (805 torr x 1 atm/760 torr)(0.335L)/(0.0821 Latm/Kmol)(298K)

n = 0.0145 moles Cl₂

Next, find out how many moles of MnO₂ are need to produce this amount of Cl₂:

0.0145 moles Cl₂ x 1 mol MnO₂/mol Cl₂ = 0.0145 moles MnO₂ needed

Finally, convert moles MnO₂ to grams MnO2 using the molar mass of 86.9 g/mole

0.0145 mol MnO₂ x 86.9 g/mol = 1.26 g MnO₂ needed