But, to be more specific, my family consists of a mother, a father, seven sons and three daughters. In this experiment, you are using this technique to experimentally determine the empirical formula of magnesium oxide. Class data could be collected for this part, so only three or four students are chewing gum outside of the lab for three 5 minute intervals. Convert these numbers to moles. Heat slowly and evenly and do not allow the flame to touch one part of the test tube for more than a couple of seconds. Its blue crystals look and feel dry, but each mole of the anhydrous salt is actually bonded to five moles of water.
Conclusions: The percentage composition of magnesium oxide is. Mass the crucible and contents. Summary In this lab, students will calculate the percent composition of sugar in gum and the percent composition of water in popcorn kernels. The contents are your new compound of magnesium oxide. The experimental data showed that the % of water in the hydrate was 51. Now you can determine the percentage of carbon in that compound. If the formula for magnesium oxide is MgO use your periodic table to calculate the theoretical percentage composition of both the magnesium and the oxygen.
Note the color change of the sample. Remass the gum, making sure it does not touch the balance. The crystals change form, and sometimes color, as the water is driven off. Heating test tubes with hydrates may result in a flash boiling of water causing a pop of materials out of the test tube. Place the kernels in the bowl.
Burner was ignited using a flint lighter to heat up the crucible containing the magnesium ribbon with the cover on 5. The molar mass is the sum of the masses of all the atoms in one mole of the compound. Lesson Problem What is the percent composition of sugar in bubble gum and water in popcorn? Use another piece of foil to cover the bowl and seal the two pieces of foil by folding them together so the popcorn does not fly out. Obtained a piece of magnesium ribbon from the teacher 2. If it doesn't, then you need to go back and find your mistake.
So, pretend you have made something in the lab. Watch for steam coming out of the test tube. Otherwise, the Bunsen burner will cause a hole to form in the bottom of the bowl. It's like saying the word family. Use aluminum foil to make a bowl for the kernels.
How might older popcorn kernels differ from the data you collected in this investigation? When referring to an unknown hydrate, you should use the notation described above. With the lid left slightly open discontinue heating. Once your kernels have all popped, take the final mass of the popcorn. Record the color, texture, and weight of this sample on the watch glass. In the second example, the product is slightly magnesium-rich; the ratio of Mg-to-O is greater than the 1-to-1 expected.
Now convert moles into grams for each constituent element as well as for the entire molecule:. Find the percentage of oxygen in the compound. Cover the crucible and heat strongly for 5 minutes or until red hot. Percentage Composition and Empirical Formulas Lab. Learn how, if given a percent composition, to determine the empirical formula for a compound. Use a 250 mL beaker as a mold for the bowl, but do not keep the foil in the beaker. Heating the product again causes the loss of water and conversion of the hydroxide to the oxide.
They should wave it occasionally and shake it several times during the popping process. The gum cannot touch the surface of the balance. Do not eat the popcorn, it should be discarded once the final data are collected. If you chewed the gum for five more minutes, what do you think would have happened? Use tongs or hot hands to touch hot glassware. Record the mass of the test tube. Determining the Percent Composition of Compounds First, let's practice finding the percent composition of compounds.