Title: What a Gas: Stoichiometry & Gas Lab Objective: To determine the starting amounts of baking soda and vinegar required to fill up a Ziploc bag. Safety: Don’t eat( Background Info: • Look up the chemical formula for baking soda and vinegar (look online, in your kitchen cabinet, in your textbook, etc) and write them here. • Write the balanced chemical equation for the reaction that takes place between baking soda and vinegar. (There are 3 products produced – one of them is a common gas.) For help, look on p. 50 in the Ultimate Chemical Equations Notebook for a similar reaction.
This gas burns completely in oxygen to form water and 72 cm3 of carbon dioxide only. All measurements are taken at room temperature and pressure. Determine the empirical formula of the binary compound. (1 mole of gas occupies 24 dm3 of volume at r.t.p) A Al2C3 B Al3C4 C Al4C3 D Al5C3 Solution no. of moles of CO2 = 72/(24 000) = 0.003 mol no.
01.07 Accuracy and Precision: Balance Lab Worksheet Calculations Show all of your work for each of the following calculations and be careful to follow significant figure rules in each calculation. Part I: Density of Unknown Liquid Calculate the mass of the liquid for each trial. (Subtract the mass of the empty graduated cylinder from the mass of the graduated cylinder with liquid.) Trial 1 36 - 25.5 = 10.5 Trial 2 36.5 - 25.5 = 11 Trial 3 36.9 - 25.5 = 11.4 Calculate the density of the unknown liquid for each trial. (Divide the mass of the liquid calculated above by the volume of the liquid.)
Gather all materials 2. Heat 200mL of water in the beaker for 90 seconds 3. Place the bulb of one thermometer just below the surface of the water 4. Record the initial temperature at the top 5. At the same time, place the second thermometer bulb just at about the bottom of the beaker 6.
The two unknown solids are weighed to a mass of 0.15g each. The unknown solids are dropped carefully into the corresponding Erlenmeyer flask wit 50mL of distilled water. The solid in the water must be dissolved and afterwards add 10 drops of Bromecresol green to indicate the change of color when the solution has been titrated. The flask should start with a blue tint. HCl is carefully dropped into the Erlenmeyer flasks with the primed pipette until the solution turn to a green tint.
Molar Volume of a Gas PRE-LAB DISCUSSION Avogadro’s hypothesis states that equal volumes of all gases contain equal numbers of molecules under the same conditions of temperature and pressure. It follows from this hypothesis that all gas samples containing the same number of molecules will occupy the same volume under the same conditions of temperature and pressure. A special name is given to the volume occupied by 1-mole samples of gases at STP. This volume is called the molar volume. In this experiment, you will make an experimental determination of the molar volume.
5. Repeat until the mass is consistent. Data and Observations: Measured melting point | 93.0 ̊ C | Real melting point | 92.5 ̊ C | Mass of evaporating dish | 47.01 g | Mass of evaporating dish and crushed alum | 49.13 g | Mass of crushed alum | 2.12 g | Mass after 1st heating | 48.17 g | Mass after 2nd heating | 48.16 g | Mass of water driven off | .97 g | Mass of anhydrous alum | 1.15 g | Moles of H2O | .0539 moles | Moles of AlK(SO4)2 | .0045 moles | Mole ratio; H2O/AlK(SO4)2 | 12.0 | During the heating of the crushed alum in the hot water bath, the alum had liquefied. The boiling point temperature that was determined was 93.0 degrees Celsius. This process had taken a long time, but around 90 degrees
Then measure the final mass of the fuel using a mass scale. Record all the results. Repeat all the steps again, but change fuel (Cheetos, half a cashew nut, wax candle and ethanol) every three trials. Data Collection and Processing: Fuel | Trials | Mass H2O (ml) ±1 | Change in Water Temperature (°C) | Mass Loss of Fuel (g) ±0.02 | Energy Produced (J) | Energy Produced per grams (J/g) | Cashew | T1 | 200 | 5 | 0.31 | 4180 | 13483.87
Using the utility clamp, clamp the thermometer, attach the paper lid to the probe then move the probe close to the bottom but not touching the magnetic stirrer. Start the Logger Pro program on the computer. Open the file “13 Enthalpy” from the Advanced Chemistry with Vernier folder. Measure 50.0 mL of 2.0 M Hydrochloric acid, HCl, solution and pour into the styrofoam cup, make sure that the temperature probe is touching the solution. Measure 50.0 mL of 2.0 M Sodium Hydroxide, NaOH, solution but DO NOT ADD YET.
Record the actual mass (1.01 grams weighed) in the results table. 2. Transfer the sample of NaOH to the 250 ml volumetric flask. 3. Put approximately 50 ml of deionized water into the flask and dissolve all of the NaOH.