LAB Molar Volume of a Gas：实验室气体摩尔体积.doc

LAB: Molar Volume of a Gas Name_______________________________ Date_________ Block____ The basis of this lab is the reaction in which a known mass of magnesium metal reacts completely with excess hydrochloric acid to produce aqueous magnesium chloride and hydrogen gas according to the following balanced equation: Mg(s) + 2 HCl(aq) → MgCl2(aq) + H2(g) Purpose: To determine experimentally the volume of 1 mole of hydrogen gas at STP. Materials and Equipment: gas-measuring tube large deep container for equalizing gas pressure in tube one-hole stopper 10-mL graduated cylinder ring stand metric ruler utility clamp access to balance Celsius thermometer safety goggles and apron 400-mL beaker magnesium ribbon, Mg(s) cotton thread 3.0 M hydrochloric acid, HCl(aq) (NOTE: 3.0 M means DI H2O(l) 3.0 moles of HCl(g) dissolved in 1.00 liter of solution) 50-mL beaker wash bottle containing NaHCO3(aq) paper towels SAFETY: Handle acids with care; ALWAYS wear safety goggles and lab aprons when working with acids. Handle the gas-measuring tube with care to avoid breakage. To clean an acid spill: dilute the acid with sodium hydrogen carbonate solution, NaHCO3(aq). Then wipe up using absorbent paper towel. It is important to “work clean;” keep your lab surface clean and dry at all times. Read and follow the directions carefully and completely! Procedure: 1. In the data table, record the mass of 1.00 m of magnesium ribbon as given by your teacher 2. Measure your piece of magnesium ribbon to the nearest 0.1 cm. Pay attention to sig. figs. Record the length of the Mg(s) ribbon in the data table. 3. Use a piece of cotton thread about 15.0 cm long. Tie one end of the thread around the Mg(s). Bend the Mg(s) so it will fit easily inside the gas-measuring tube. 4. Measure about 10.0 mL HCl(aq). Caution: handle acids with care! Carefully pour the HCl(aq) into the gas-measuring tube. 5. Pour about 40. mL D