PLEASE HELP!!



Given the following balanced reaction between hydrochloric acid and oxygen gas to produce water and chlorine gas, how many grams of chlorine gas, Cl2, are produced from 27.8 g of hydrochloric acid and excess oxygen? (To find the molar mass in the problem, use the periodic table and round the mass to the hundreds place for calculation.)

4HCI(aq) +O2 ->2CI2 (g)+ 2H2O (I),

Respuesta :

number of moles of HCl = [tex] \frac{mass (g)}{molar mass} [/tex]
                = [tex] \frac{27.8 g}{36.45} [/tex] = 0.763 mole
From balanced equation:
4 moles of HCl give 2 moles Cl2
0.763 mole HCl give ?? mole Cl2
by cross multiplication :
= 0.38 mole Cl2
mass of Cl2 = moles x molar mass = 0.38 x 70.9 = 27 g 

Answer : The mass of chlorine gas produced are, 26.95 grams.

Explanation : Given,

Mass of HCl = 27.8 g

Molar mass of HCl = 36.46 g/mole

First we have to calculate the moles of hydrochloric acid.

[tex]\text{Moles of HCl}=\frac{\text{Mass of HCl}}{\text{Molar mass of HCl}}=\frac{27.8g}{36.46g/mole}=0.76mole[/tex]

Now we have to calculate the moles of chlorine gas.

The given balanced chemical reaction is,

[tex]4HCI(aq)+O_2\rightarrow 2CI_2(g)+2H_2O(I)[/tex]

From the given balanced chemical reaction, we conclude that

As, 4 moles of hydrochloric acid react to give 2 moles of chlorine gas

So, 0.76 moles of hydrochloric acid react to give [tex]\frac{2}{4}\times 0.76=0.38[/tex] moles of chlorine gas

Now we have to calculate the mass of chlorine gas.

[tex]\text{Mass of }Cl_2=\text{Moles of }Cl_2\times \text{Molar mass of }Cl_2[/tex]

Molar mass of [tex]Cl_2[/tex] = 70.91 g/mole

[tex]\text{Mass of }Cl_2=0.38mole\times 70.91g/mole=26.95g[/tex]

Therefore, the mass of chlorine gas produced are, 26.95 grams.