posted by .

The reaction for my lab is
Mg(s)+2HCl(aq)--> MgCl2(aq)+H2(g)

I need to find the pressure of the hydrogen gas.
Initial Pressure = 0.98692 atm
Total Pressure = 1.64816 atm

I don't know if I calculated the pressure of hydrogen gas correctly. I used the formula Total Pressure=Initial Pressure+Pressure of H2+Pressure of H2O
This is what I got for an answer.
Pressure of H2=1.64816-0.98692-0.0313=0.6926atm

  • Chemistry -

    Where did the 1.64816 come from?
    Usually these are done by collecting H2 gas over water. Then the room pressure, which I assume is the 0.987 atm - vapor pressure of water at room T is pressure of dry H2 gas at those conditions. This assumes the pressure inside the collection vessel and outside the vessel were the same.

  • Chemistry -

    In the lab I had a strip of magnesium that weighed 0.029 grams and I added 15 milliliters of 0.5 M hydrochloric acid into a flask and I never used any water during the lab. So I don't really understand where I would get the water vapor pressure.

  • Chemistry -

    OK. I don't know what you did. You must have generated the H2 gas and measured the total pressure at the end. So total P - pH2O - initial P would be P of dry H2. If so what you have looks ok to me. The vapor pressure of the water must be the 0.0313 (that's equivalent to 23.7 mm Hg which is about right for a temperature of 25C.

  • Chemistry -

    The pressure of the water vapor comes from the water in the HCl(aqueous).

  • Chemistry -

    Oh ok and I used a device called a Xplorer GLX and it measured the pressure of the flask before I put in the magnesium and hydrochloric acid and then it measured the pressure once the reaction was complete. But thank you for all of your help!

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. chemistry

    ideal gas .450 mole initial pressure 16 atm and 290 K expands isothermally to a final pressure 1 atm. find work , if expansion is against a vacuum, a constant external pressure of 1 atm and reviersibly
  2. chemistry(total pressure)

    Two cylinders at 27C are connected by a closed stopcock ystem. One cyclinder contains 2.4 L of hydrogen gas at o.600 atm; the other cylinder contains 6.8L of helium at 1.40 atm. Assume valve take up no room. what is the total pressure …
  3. Chemistry

    In an experiment, 238 mL of 0.45 molar hydrochloric acid completely reacts with excess iron to produce hydrogen gas and iron (III) chloride. What volume will the hydrogen gas occupy if it is collected over water at 35 degrees Celsius …
  4. Chemistry

    FeS2 (s) + O2(g) -----> SO2(g) +Fe203(s) (unbalanced) a production error leads to the sulfide being placed in a 950-L vessel with insufficient oxygen. Initially, the partial pressure of O2 is 0.64 atm, and the total pressure is …
  5. Chemistry

    Sulfur dioxide is used to make sulfuric acid. one method of producing it is by roasting mineral sulfides, for example, FeS2(s) + O2 (g) ---> SO2(g) + Fe2O3(s) (unbalanced). A production error leads to the sulfide being placed in …
  6. chemistry

    The pressure in a constant-volume gas thermometer is 0.700 atm at 100°C and 0.512 atm at 0°C. (a) What is the temperature when the pressure is 0.0500 atm?
  7. chemistry

    A mixture og gases has a total pressure off 28.3 atm, it is made of: 5.8 atm of hydrogen gas, 7.2 atm of nitrogen gas, 3.5 atm of oxygen gas and some amount of methane. What is the pressure of methane?
  8. chemisrty

    What is the total pressure of the gas produced in the burette if it contains nitrogen gas whose pressure is 1.5 atm, oxygen gas whose pressure is 1.6 atm and water vapour with a pressure of 1.3 atm.
  9. Physical Chemistry

    Calculate the work, w, (in J) when 0.6 litre of an ideal gas at an initial pressure of 91.5 atm is expanded isothermally to a final pressure of 2.15 atm against a constant external pressure of 2.15 atm. I got -130.71 J, but apparently …
  10. Chemistry

    1) 0.19 litre of an ideal monatomic gas (Cv,m = 3R/2) initially at 83 °C and 47 atm pressure undergo an expansion against a constant external pressure of 1.19 atm, and do 2.3 kJ of work. The final pressure of the gas is 1.19 atm. …

More Similar Questions