Consider the following reaction in water:

P4 (s) + 6 H2O (l) → 2 PH3 (g) + 2 H3PO3 (aq)

If you allow 23.42 g of P4 to react what would be the pressure that the dry gas would exert on a 15.00
mL container at STP. Assume all of the phosphorus reacted.

This can be solved by finding the partial pressures of the reactants correct?

well, you get 2 moles of gas for each mole of P4.

moles P4=23.42g/4*30.97=.189moles
Moles gas=2*.189

PV=nRT
P=nRT/V=
solve for P.

Yes, you are correct. To solve this problem, you can use the concept of partial pressures of the reactants involved in the reaction. In this case, since the reaction produces a gaseous product (PH3), you can find the pressure the dry gas would exert on the container at STP.

To find the partial pressures, you need to use the ideal gas law, which states:

PV = nRT

Where:
P = pressure (in atm)
V = volume (in liters)
n = number of moles
R = ideal gas constant (0.0821 L·atm/mol·K)
T = temperature (in Kelvin)

Since the problem specifies that the container is at STP (standard temperature and pressure), the temperature will be 273.15 K and the pressure will be 1 atm.

Let's go step by step to find the partial pressure of PH3 in the container:

1. Calculate the number of moles of P4:
To find the number of moles of P4, you can use its molar mass. The molar mass of P4 is 123.9 g/mol. Thus, the number of moles can be calculated using the following equation:

moles of P4 = mass of P4 / molar mass of P4

moles of P4 = 23.42 g / 123.9 g/mol

2. Calculate the number of moles of PH3:
The balanced equation tells us that 1 mole of P4 reacts to form 2 moles of PH3. Therefore, the number of moles of PH3 can be calculated as follows:

moles of PH3 = (moles of P4) x 2

3. Use the ideal gas law to find the pressure:
Finally, you can use the ideal gas law to find the pressure of the PH3 gas in the container. Since the volume is given as 15.00 mL, it needs to be converted to liters:

V = 15.00 mL = 0.015 L

Now, substitute the values into the ideal gas law equation:

P x 0.015 L = (moles of PH3) x 0.0821 L·atm/mol·K x 273.15 K

Solving for pressure (P):

P = (moles of PH3) x 0.0821 L·atm/mol·K x 273.15 K / 0.015 L

Plug in the calculated value of moles of PH3 to find the pressure exerted by the dry gas on the container at STP.