how many liters of oxygen are required to react completely with 12.5 liters of hydrogen sulfide at stp?

You need an equation and it must be balanced.

Convert 12.5 L H2S to mols. That is 12.5L/22.4 = ? mols H2S.

Use the coefficients in the balanced equation to convert mols H2S to mols Oxygen.

Now convert mols oxygen to L.
mols O2 x 22.4L= ?

There is a shortcut you can use if you wish. Since all are gases, you may omit the mols step at the front and back and just convert L H2S to L O2 directely using the coefficients as above

To find the number of liters of oxygen required to react completely with 12.5 liters of hydrogen sulfide (H2S) at STP (Standard Temperature and Pressure), we need to use the molar ratio from the balanced chemical equation for the reaction between hydrogen sulfide and oxygen.

The balanced equation for the reaction is:

2 H2S + 3 O2 → 2 SO2 + 2 H2O

From the balanced equation, we can see that 2 moles of H2S react with 3 moles of O2. Therefore, the mole ratio between H2S and O2 is 2:3.

First, we need to determine the number of moles of H2S in 12.5 liters. To do this, we use the ideal gas law equation: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature.

At STP, the pressure is 1 atm and the temperature is 273 K.

Using the equation PV = nRT, we can rearrange it to solve for n (number of moles):

n = PV / RT

n = (1 atm) * (12.5 L) / (0.0821 L·atm/(mol·K)) * (273 K)

n = 0.577 moles

Next, we use the mole ratio between H2S and O2 to find the number of moles of O2 required. Since the ratio is 2:3, we can set up a proportion:

2 moles H2S / 3 moles O2 = 0.577 moles H2S / x moles O2

Simplifying the proportion, we find:

(2/3) = (0.577 / x)

Cross-multiplying:

2x = 3 * 0.577

x = 3 * 0.577 / 2

x ≈ 0.866 moles

Finally, we convert the moles of oxygen back to liters by using the ideal gas law:

V = nRT / P

V = (0.866 mol) * (0.0821 L·atm/(mol·K)) * (273 K) / (1 atm)

V ≈ 19.77 liters

Therefore, approximately 19.77 liters of oxygen are required to react completely with 12.5 liters of hydrogen sulfide at STP.