# The molar relationship involving mass and volume lab

### The molar relationship involving mass and volume lab? | Yahoo Answers

calculate the mass of magnesium by using the known mass per Chemistry Forums · High School Chemistry; I had to complete a lab for molar volume of a gas. what is the molar relationship between the mg and the h2. THE MOLAR RELATIONSHIP. INVOLVING MASS AND VOLUME. Both solids and gases must often be handled in the same experiment. The amount of solid. Mg + 2 HCl = MgCl2 + H2 the molar relationship between Mg and H2 is 1: 1 moles H2 = X volume of H2 (at STP) = X V = nRT/p = 1 x.

Clamp the tube into place with the utility tube so that the bottom of the tube is slightly above the bottom of the beaker. You have to wait for the acid to diffuse down through the water to reach the Mg. When the Mg has reacted completely and the evolution of gas has stopped, tap the tube with your finger to dislodge any bubbles you see attached to the side of the tube.

Place your finger over the hole in the stopper and remove the tube from the beaker. Lower the tube into the larger container of water used to equalize pressure and remove your finger. Raise or lower the tube until the level of the water inside the tube is the same as the level of water outside the tube. Read the scale on the tube as accurately as possible to the nearest 0. This will give the volume of the gases hydrogen and water vapor in the tube. Record the volume in your notebook.

Empty the contents of the tube and beaker and rinse both with tap water. Record the temperature in degrees Celsius, the barometric pressure and the precise mass of the Mg ribbon.

Clean up your area. Calculate the moles of magnesium in the sample. Calculate the partial pressure of hydrogen gas in the hydrogen gas-water vapor mixture. For the partial pressure of water vapor at different temperatures, consult a reference. Also, remember that the total pressure of a gas mixture is equal to the sum of the partial pressures of each gas: Dalton's Law of Partial Pressures 2 2 3. At this point, you know: You should now be able to use the ideal gas law to calculate the number of moles of hydrogen gas present.

From your calculations, a fractional part of a mole of magnesium gave an experimentally determined volume of H2 gas. Use this information to determine the correct chemical equation. Start by writing down the reactants and products; this is the skeleton chemical equation. Now compare the moles of magnesium to moles hydrogen gas produced and this should give you an idea about the chemical equation.

Calculate how many liters the hydrogen would occupy if you had one mole of gas at STP.

## Unit 5 Lab 1

Do this by comparing the ideal gas law for two situations: If pieces of magnesium float to the surface, students must shake the tube to submerge the magnesium. 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. Rinse gas measuring tubes with water.

Dissolve any unused magnesium ribbon in very dilute HCl. Predict the effect of replacing magnesium with zinc.

Zinc will react but less vigorously. 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. Calculate the number of moles of magnesium used in the experiment.

Calculate the partial pressure of hydrogen gas in the hydrogen gas-water vapor mixture.

### | CK Foundation

Use the gas laws to calculate the volume which would be occupied by the gas at standard temperature, K, and standard pressure, Use the volume of hydrogen gas from the experiment at the corrected pressure Question 3 and room temperature.

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. Use the data to calculate the volume of H2 that would be produced by one mole of magnesium reacting with excess HCl at STP. The reactants in this experiment are known.

One of the products is hydrogen gas. If the water in the tube is evaporated, the other product, a white salt, remains. Write the balanced chemical equation for this reaction.

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