Laboratory Techniques and Measurements

Laboratory Techniques and Measurements Final Report Student Name Student ID Lesson t Institution Session Course Instructor Test Your Knowledge 1. Rank the measurements in order from smallest to largest. 3.0 x 10 -7 m 2.0 x 10 -6 m 1.0 x10 -5m 1.0 m 3 4.0 x 10 mm 2. Match each SI base unit to the appropriate measurement. Length Mass Time Temperature Amount of Matter 1 2 3 4 5 meter kilogram second kelvin mol 3. Perform the following conversions. 345.7 K Convert 61° F to °C 1 16° C 12° C Convert 19.4° C to K 2 292.6 K Convert 15.3 mm to cm 3 1.53 cm Convert 4.25 cm to m 4 0.0425 m Convert 218.4 g to kg 5 0.2184 kg 2.53 cm 0.425 m 2.184 kg Exploration 1. A micrometer is equal to 0.000001 m. True False 2. The SI system is derived from the _____. United States system metric system English unit system math system 3. Every measuring device measures length to the same degree of accuracy and precision. True False 4. The SI system unit for temperature is _____. degrees Celsius degrees Fahrenheit kelvin 5. One liter is equal to _____. 1 cm3 10 cm3 100 cm3 1,000 cm3 6. A meniscus is the curve that forms between the liquid and the surface of the container. True False 7. Graduated cylinders and graduated pipets are designed to measure _____ volume(s). a range of only one 8. Archimedes’ method is used to measure the volume of a(n) _____. square rectangle irregularly shaped object 8. Density is derived from SI units of __________ and ___________. volume; length mass; amount of substance length; mass mass; volume 10. In the equation C x V =1C x V 1 , C 2 represents 2 1 the _____ of the solution. initial concentration initial volume final concentration final volume 11. The final digit in any measurement is the estimated, uncertain digit. True False Exercise 1 1. Water boils at 100°C at sea level. If the water in this experiment did not boil at 100°C, what could be the reason? My water started boiling at 89.8C one of the reasons was because I measured the water when I started seeing bubbles, therefore maybe my water wasn't technically boiling when I measured it. Also 2. While heating two different samples of water at sea level, one boils at 102°C and one boils at 99.2°C. Calculate the percent error for each sample from the theoretical 100.0°C. 1 water boils at 102C = 2% error 2 water boils at 99.2C = 0.8% error Data Table 1: Length Measurements Length (cm) Length (mm) Length (m) CD or DVD 12.0 120 0.12 Key 5.2 52 0.052 Spoon 15.3 153 0.153 Fork 15.8 158 0.158 Data Table 2: Temperature Measurements Temperature (°C) Temperature (°F) Temperature (K) Hot from Tap 54.0 129.2 327.12 Boiling 89.8 193.8 363.1 Boiling for 5 minutes 108.2 226.8 381.4 Cold from Tap 24.5 76.1 297.7 Ice Water - 1 minute 1.5 34.7 274.7 Ice Water - 5 minutes -1.5 29.3 271.7 Data Table 3: Mass Measurements Estimated Mass (g) Actual Mass (g) Pen or Pencil 6 4.55 .00455 3 Pennies 7 7.4 0.074 1 Quarter 4 5.7 0.0057 2 Quarters, 3 Dimes 12 18.2 0.0182 4 Dimes, 5 Pennies 15 22.1 0.0221 3 Quarters, 1 Dime, 5 Pennies 30 32.3 0.0323 Key 5 7.4 0.0074 Key, 1 Quarter, 4 Pennies 20 23.7 0.0237 Exercise 2 1. An unknown, rectangular substance measures 3.60 cm high, 4.21 cm long, and 1.17 cm wide. If the mass is 21.3 g, what is this substance’s density (in grams per milliliter)? 0.00123g/mm3 2. A sample of gold (Au) has a mass of 26.15 g. Given that the theoretical density is 19.30 g/mL, what is the volume of the gold sample? 1.35g/cm3 Actual Mass (kg) 3. A student was given an unknown metal. The student determined that the mass of the metal was 30.2 g. The student placed the metal in a graduated cylinder filled with 20.0 mL of water. The metal increased the volume of water to 22.9 mL. Calculate the density of the metal and determine the identity of the metal using the table below. 10.41g/cm3 silver Data Table 4: Liquid Measurements Water Isopropyl Alcohol Mass A: Graduated Cylinder (g) 17.42 17.42 Volume (mL) 5.0 5.0 Mass B: Graduated Cylinder with Liquid (g) 22.41 21.67 Mass B-A: Liquid (g) 4.99 4.24 Density (g/mL) 1.49 .90 Percent Error (%) 28 24 Data Table 5: Magnet - Direct Measurement Method Magnet Mass (g) 4.23 Length (cm) 2.5 Width (cm) 0.6 Height (cm) 2.5 Volume (cm ) 3.75 3 Density (g/cm ) 3 0.88 Data Table 6: Water Displacement Method Magnet Metal Bolt Mass (g) 4.21 7.53 Initial Volume of Graduated Cylinder (mL) 6.5 7.5 Final Volume of Graduated Cylinder (mL) 7.5 8.5 Object Volume (mL) 1.0 1 Density (g/mL) 1.54 1.01 Exercise 3 1. How would you prepare 10 mL of a 0.25% m/v HCl solution if 1% m/v HCl was available? How much 1% m/v HCl is needed? How much distilled water is used? It would be a 1:4 solution water needed 2.5mL 4mL of .25% 2. From the graph of Density vs. Concentration, created in Graph 1, what was the relationship between the concentration of the sugar solution and the density of the sugar solution? relationship is concentrated Data Table 8: Initial Concentration Sugar (C12 H22 O11 ) Mass of Volumetric Flask (g) 26.40 Mass of Sugar (g) 8.00 Total Volume (mL) 54.27 Concentration (% m/V) .0015 Data Table 9: Solutions Solution Volume (mL) Mass (g) Density (g/mL) 0 25.00 mL 29.24 1169.9 1 25.00 mL 25.23 1009.2 2 25.00 mL 31.53 3 25.00 mL 4 25.00 mL Volume Transferred (mL) Final Concentration (% m/v) 0 1369.2 1369.2 2.5 2948.3 1261.2 1369.2 4.5 3684.4 28.20 1128 1369.2 3.0 3295.3 40.63 1625.2 1369.2 6.0 4747.9 Graph 1: Density versus Concentration Initial Concentration (% m/v) Competency Review 1. The SI system unit for the amount of a substance is _____. grams per liter moles Avogadro's number kilograms 2. The International System of Units (SI) is _____. a scale of measurement the same as U.S. Customary Units the same as English units a standard system to measure length, temperature, time, amount of substance, and mass 3. Convert 15.00 F to oC. o o 1.58 C o 8.33 C o -9.40 C 59 oC o -8.7 C 4. Convert 5.00 miles to kilometers. 8.05 km 3.11 km 2.49 km 1.53 km 5. A meniscus is the curve that forms between the liquid and the surface of the container as the result of surface tension, cohesion, and adhesion. True False 6. _____ is defined as mass per unit of measure. Volume A kilogram Molarity Density Concentration 7. The definition of % m/V is _____. grams solute/mL solution x 100 grams solution/mL solute x 100 mL solute/grams solution x 100 mL solution/grams solute x 100 8. Significant figures include only the certain digits of a measurement. True False 9. When reading a graduated cylinder made of glass, one must read the volume at eye level from the middle of the meniscus. True False 10. A volumetric flask contains 25.0 mL of a 14% m/V sugar solution. If 2.5 mL of this solution is added to 22.5 mL of distilled water, what is the % m/V of the new solution. 1.4 % m/V 14 % m/V 7.1 % m/V 71 % m/V 11. Calculate experimental error using the following data: the measured value equals 1.4 cm; the accepted value equals 1.2 cm. -14.3% 14.3% -16.7% 16.7% 12. What is the volume of an irregularly shaped object that has a mass 3.0 grams and a density of 6.0 g/mL? 1.0 mL 0.5 mL 2.0 mL 18.0 mL Extension Questions In the movie, "Raiders of the Lost Ark", Indiana Jones takes a gold idol from a cave. The statue is resting on a table which is rigged with a weight sensor. The weight sensor can detect when the weight is removed and will set off a series of unfortunate accidents. To prevent this from happening, Indiana replaces the gold idol with a bag of sand. The volume of the gold idol is approximately 1.0 L. The density of gold is 19.3 g/mL and the density of sand is 2.3 g/mL. 1. a. Assuming the idol is pure gold, what volume would the bag of sand have to be in order to weigh exactly the same as the idol and not set off the booby-traps? b. Let’s assume that Indiana is successful in removing the idol and returning with it to his laboratory. He decides to determine if it is really pure gold. He weighs the idol and measures the volume by a water displacement method. The results are: mass = 16.5 kg and volume of water displaced = 954 mL. Is the idol made of pure gold? Explain your answer based on the experimental results. 1a. 8.392L or 8391mL 1b.No it was not made of pure gold it was mixed with a less dense metal. solvent density is 17.3g/mL there's a differnce between them.