peice of sodium metal reacts with water. 246ml volume of hydrogen gas was collected over water at 25 celsius and at an atmospheric pressuric pf 101.3 kpa.

what was the pressure of dry hydrogen?
what is the mass of sodium used up by the reaction?

2Na + 2H2O ==> H2 + 2NaOH

Ptotal = pH2 + pH2O
Ptotal = 101.2 kPa
pH2O = look up vapor pressure H2O at 25 C. Substitute and solve for pH2. That will be pressure of dry H2.

Use PV = nRT and solve for n. Use dry H2 for P. If you use 101.3 then use 8.314 for R. Remember T must be in kelvin. Solve for n.

Then convert mols H2 to mols Na (from the equation) and convert to grams Na used. g = mols x atomic mass.

is the dry hydrogen 98.13kpa?

and is the mass 224.1g?

To find the pressure of dry hydrogen gas and the mass of sodium used up by the reaction, we can follow these steps:

Step 1: Convert the volume of hydrogen gas collected over water to the volume of dry hydrogen gas.
Step 2: Apply the ideal gas law to find the pressure of dry hydrogen gas.
Step 3: Determine the moles of hydrogen gas produced using the volume and the ideal gas law.
Step 4: Calculate the moles of sodium reacted based on the balanced chemical equation.
Step 5: Convert moles of sodium to mass using the molar mass of sodium.

Let's go through each step in detail:

Step 1: Convert the volume of hydrogen gas collected over water to the volume of dry hydrogen gas.
When collecting a gas over water, we need to correct for the water vapor's partial pressure. At 25 degrees Celsius, the vapor pressure of water is approximately 3.17 kPa. To calculate the volume of dry hydrogen gas, subtract the vapor pressure of water from the atmospheric pressure:

V_dry = V_wet - P_water vapor

V_wet = 246 mL (given)
P_water vapor = 3.17 kPa (vapor pressure of water at 25°C)

Step 2: Apply the ideal gas law to find the pressure of dry hydrogen gas.
The ideal gas law equation is:

PV = nRT

P: Pressure (unknown)
V: Volume of dry hydrogen gas (calculated in Step 1) = V_dry
n: Number of moles of dry hydrogen gas (unknown)
R: Ideal gas constant = 8.314 J/(mol·K)
T: Temperature in Kelvin = 25°C + 273.15 = 298.15 K

Solve for P to find the pressure of dry hydrogen gas.

Step 3: Determine the moles of hydrogen gas produced using the volume and the ideal gas law.
Using the ideal gas law again, rearrange the equation to solve for n:

n = PV / RT

P: Pressure of dry hydrogen gas (calculated in Step 2)
V: Volume of dry hydrogen gas (calculated in Step 1) = V_dry
R: Ideal gas constant = 8.314 J/(mol·K)
T: Temperature in Kelvin = 25°C + 273.15 = 298.15 K

Step 4: Calculate the moles of sodium reacted based on the balanced chemical equation.
The balanced chemical equation for the reaction between sodium and water is given by:

2 Na + 2 H2O -> 2 NaOH + H2

From the equation, we see that 2 moles of sodium react to produce 1 mole of hydrogen gas. Therefore, the number of moles of sodium reacted is half the number of moles of hydrogen gas produced.

Step 5: Convert moles of sodium to mass using the molar mass of sodium.
The molar mass of sodium (Na) is approximately 22.99 g/mol. Multiply the number of moles of sodium reacted (calculated in Step 4) by the molar mass to find the mass of sodium used up by the reaction.

By following these steps, you should be able to determine the pressure of dry hydrogen gas and the mass of sodium used up by the reaction.