# An experiment to calculate the molar volume of hydrogen gas at standard temperature and pressure

Rinse gas measuring tubes with water. Repeat Steps 3 -7 with the other 2 pieces of magnesium. Write the balanced chemical equation for this reaction.

Gas bubbles are observed when the acid diffuses down to the metal sample. The reaction may take a few minutes. To make the experiment more interesting vary the size of the magnesium ribbon between 3 cm and 5 cm so that all lab groups will not obtain the same volume of hydrogen gas.

Mathematically this is expressed as: Invert the graduated cylinder over the sink and carefully place the cylinder into the bowl. If pieces of magnesium float to the surface, students must shake the tube to submerge the magnesium. From the balanced equation in question 1, determine the molar relationship between the solid Mg and the H2 gas.

The copper can be dried and recycled with metals or you can dispose of it in the garbage. Wrap the 1st piece of metal in the strand or strands of copper turnings. The atmospheric pressure is listed under the current conditions and is listed in units of inches of Hg. Calculate your percent error and list your major sources of error.

Polish 1 meter of magnesium ribbon using steel wool, emery cloth, or fine sand paper. One or two drops of food coloring or indicator placed in the acid will help the students both see the movement of the HCl through the water in the tube and also read the meniscus in the gas-measuring tube after the reaction.

Measure the length; record. You want it to slightly bubble over the top. Compare the value obtained in question 4 with the theoretical value for the volume of one mole of hydrogen gas at STP, 22, cm3. The paper towel should wet completely and there may be just a little spillage.

The volume of H2 produced by the amount of magnesium used in this experiment can be converted to the theoretical volume of H2 that would be produced by one mole of magnesium at STP.

It is not a reactant in the chemical reaction. Answers to Closure Questions: Zinc releases less hydrogen per gram than does magnesium.

Calculate the mass of magnesium used in the experiment by using the known mass per meter of ribbon. Predict the effect of replacing magnesium with zinc. The liquid will not spill when the lip of the graduated cylinder is beneath the liquid level in the bowl, so you can swish it around just a little to move the paper out of the way and put the cylinder over the metal.

The reactants in this experiment are known. To convert this to torr, multiply by Go onto a weather website and find the atmospheric pressure you can also call your local airport to get this information. If the water in the tube is evaporated, the other product, a white salt, remains.

Zinc will react but less vigorously. Dissolve any unused magnesium ribbon in very dilute HCl. Place a thermometer into the bowl of water. Air in the gas-measuring tube will produce erroneous results. If fragments of magnesium metal stick to the tube wall, the student should place a finger over the open end of the tube and tilt the tube to wash the magnesium back into the solution.

Your magnesium should completely react. The total pressure caused by these two gases was made equal to room pressure. The strip may already be in pieces; use all of it so you have 3 semi-equal pieces.

Weigh, and record the mass. If you choose another site, it might be found under atmospheric data. Calculate the number of moles of magnesium used in the experiment. The pressure of the water vapor can be ascertained from a table of water vapor pressures.Using the combined gas law, calculate the volume occupied by the H 2 gas at STP ( K and kPa).

Use this volume and the number of moles of hydrogen calculated earlier to find the standard molar volume of hydrogen. LAB: THE MOLAR VOLUME OF A GAS Introduction Today you are going to prove experimentally that the volume of one mole of a gas at standard temperature & pressure (STP) occupies Find the vapor pressure of water at the temperature of your experiment.

5. Calculate the partial pressure of your hydrogen gas sample. Molar volume of the ideal hydrogen gas at room temperature (Volume/moles), expressed as L/mol at X degrees C and a pressure of 1 atmosphere = L/mole * moles = L or mL 2.

For the second part of the experiment, everything was the same except that twice as much Zn was used. The purpose of this section is to calculate the molar volume (volume of one mole) of hydrogen gas at standard temperature and pressure.

Questions: 1. Determine the mass of the magnesium you used. Use the grams per meter and the length of your piece of The Reaction of Magnesium with Hydrochloric Acid KEY In this experiment you. The molar volume of the gas at a particular temperature and pressure is independent of the type of gas.

In this experiment, hydrogen gas generated by the reaction of magnesium with hydrochloric. I had to complete a lab for molar volume of a gas. use the gas laws to calculate the volume that would be occupied by the gas at standard temperature and pressure ( K and mm).

use the volume of the hydrogen gas (from our experiment) at the corrected pressure (calculation 2 at room temperature) part of a mole of .

An experiment to calculate the molar volume of hydrogen gas at standard temperature and pressure
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