Question

Given the following reaction:1 H2 (g) + 1 Cl2(g) =2 HClHow many liters of hydrogen gas are needed to react completely with 3.55 L of chlorine gas at 755 torr and 29.0 C ?

Answer 1

3.54 L of hydrogen gas (H2).

Step-by-step explanation:

What is given?

Volume (V) = 3.55 L.

Pressure (P) = 755 torr = 0.993 atm. (1 atm = 760 torr)

Temperature (T) = 29.0 °C + 273 = 302 K.

R = 0.082 atm*L/mol*K.

Step-by-step solution:

Let's use the ideal gas formula:

`PV=nRT.`

Where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant and T is the temperature on Kelvin scale. Let's solve for 'n', the number of moles of chlorine gas (Cl2):

`n=(PV)/(RT)=\frac{0.993\text{ atm}\cdot3.55\text{ L}}{0.082(atm\cdot L)/(mol\cdot K)\cdot302K}=0.142\text{ moles.}`

Now, let's see how many moles of H2 are required to react with 0.142 moles of Cl2.

In the chemical equation, you can see that 1 mol of H2 reacts with 1 mol of Cl2 too, so the molar ratio between them is 1:1. This means that 0.142 moles of Cl2 will react with 0.142 moles of H2 too.

As they're reacting in a determined place with given pressure and temperature conditions, we just have to replace 'n = 0.142 moles H2' when we solve for 'V', like this:

`V=(nRT)/(P)=\frac{0.142\text{ moles}\cdot0.082(atm\cdot L)/(mol\cdot K)\cdot302K}{0.993\text{ atm}}=3.54\text{ }L.`

The answer is that we require 3.54 L of hydrogen gas (H2) to react with chlorine gas (Cl2).