ࡱ;  R F@CompObj\WordDocument[#ObjectPool FMicrosoft Word 6.0 DocumentNB6WWord.Document.6;  Oh+'0  ! -9A IUr z5Science F:Microsoft Office:Microsoft Word 6:chem labLAB: TITLE OF LABsciencescience'@K]@ a@:Ҟ@ܥhO e[# 4V!V!V!V!V!(~! !V!F"V!!!!!!!!" " " " " " "&"X"gF" ! !@!!!F"! !!!!!! ! !"! !6 !"!:!Lab: MOLAR VOLUME  Introduction Magnesium reacts with excess hydrochloric acid in a single replacement reaction to produce magnesium chloride and hydrogen gas: Mg(s) + 2HCl(aq) ( MgCl2(aq) + H2(g) Notice the stoichiometry. For every mole of magnesium used in this reaction, one mole of hydrogen gas will be produced. In this lab, a small amount of hydrogen will be generated from a known amount of magnesium. The volume, temperature and pressure of the hydrogen will be determined and converted to standard conditions (STP). The molar volume will then be calculated from the volume of dry hydrogen and the number of moles of hydrogen. MATERIALS: 0.5 cm of magnesium ribbon thin copper wire small 10.0 mL graduated cylinder one whole rubber stopper to fit the graduated cylinder 400 mL beaker 3.0 M hydrochloric acid (HCl) Procedure 1. Measure and record the exact length of the piece of magnesium ribbon. (Your teacher will give you the mass of exactly 100.0 cm of magnesium ribbon.) 2. .Wrap the copper wire around the magnesium ribbon, making a cage that surrounds the ribbon, but leaves a 6 cm handle on the copper wire. (see diagram 1) 3. Insert the handle end of the copper wire into the one-hole stopper . (see figure 2) 4. Pour 3 mL of hydrochloric acid into the graduated cylinder. Then fill the rest of the cylinder to the very top with water. and insert the rubber stopper so that the wire cage with the magnesium will be inside the cylinder. 5. Fill the 400 mL beaker 3/4 full of water. Holding your finder over the hole in the rubber stopper, quickly invert the cylinder into the beaker of water. You may rest the cylinder against the side of the beaker. (see diagram 3). 6. When the Mg ribbon is no longer reacting, tap the side of the cylinder to release any trapped bubbles. 7. Now read and record the temperature in the beaker. 8. Read the barometer and record the barometric pressure in the lab. 9. Determine the water vapor pressure from your reference table and record it in the data table. 10. Lift the graduated cylinder slightly until the levels of water inside and outside the cylinder are the same. Read and record the volume of hydrogen gas in the graduated cylinder. (Remember that you are reading an inverted cylinder. 11. Clean up your equipment carefully since hydrochloric acid is still present in your beaker. Data length of magnesium ribboncmmass of 100.0 cm of magnesium ribbongtemperature of the reaction systemoCatmospheric pressuremm Hgwater vapor pressure at reaction temperaturemm Hgvolume of hydrogen gas producedmL Calculations 1. Calculate the number of moles of magnesium that reacted, using the length of the magnesium ribbon you used and the mass of 100.0 cm of ribbon and the molar mass of magnesium. 2. Calculate the moles of hydrogen that were produced. (HINT: examine the stoichiometry of this reaction) 3. Using the gas laws, calculate the volume of hydrogen that would have been produced had this reaction been done at STP. 4. Knowing the number of moles of hydrogen that were produced (#2) and the volume it would occupy at STP (#3), calculate the volume that one mole of hydrogen would occupy at STP. 5. The accepted value for the volume occupied by a mole of gas is 22.4 L at STP. Calculate your percent error. Analysis 1. Why is it necessary to subtract the value of water vapor pressure from the atmospheric pressure to determine the pressure of the hydrogen gas. 2. What evidence of a chemical did you observe? 3. At the end of the reaction, how did the appearance of the copper wire compare with that of the magnesium 1. 2. 3. GASES Name: _______________________ Partner #1: _______________________ Partner #2: _______________________ Acton-Boxborough Regional High School Due Date: ______________________ Acton-Boxborough Regional High School ?|HH(EG(HH(d'p|HH(EG(HH(d'p |HH(EG(HH(d'p00&ta0`0(00&00&00&00&00&ࡱ; SummaryInformation(Microsoft Word 6.0.18ࡱ; #VWa^ _ ` e J K X 01:,Uz~LuU]cU]c]hJ]]uD]a UZ]c( UZ]c($#$KYZ+)7UVab 0 f  [ \ ] ^ _ e f $$$,$$$$$$$$$$$$$$$$$$$$$,$h*f  $ % E H I J X }~+,-.$$,$$$$$$$$$$$$$$$$$$$$l H$(./0:jklmnopqrstuvwxyz{|}~$$$,$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ h !s0h !sh'NOPQRSTU|}~$$$h 0 !lK@Normal]a "A@"Default Paragraph Font @ Header ! @ Footer !*O"* Chem HeaderL UZ]cb_  "b_ X qsL f . V_ J 0 ,\:science/Science F:Teacher Folders:Murphree:MOLAR VOLUME@ &VMTimes New Roman Symbol MArial MTimesMNew Century Schlbk"1hC{&&&F&FJ9g4Science F:Microsoft Office:Microsoft Word 6:chem labLAB: TITLE OF LABsciencescienceࡱ;