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Unit 1 Review Name: Measurement and Uncertainty 1. When looking at a measuring tool, how will you decide the uncertainty (+/-)? Period: 2. In the following numbers, circle the estimated digit. What were the smallest markings on the measuring tool? a. 3.5 m b. 3.5 cm c. 22.8 mL 3. Read the graduated cylinder to the right. Circle the estimated digit and include units and uncertainty in your answer. ____________ Conversions between units Use your knowledge of the metric system to complete the following conversions. Show your work using Dimensional Analysis. 4. 5.6 kg = _____ g 6. 120. mg = _____ g 5. 1 cm = _________μm 7. 6.3 cm = ____mm 3 mL 8. What are the 3 conversions you know for moles? a. 1 mol = _____________ b. 1 mol = _____________ c. 1 mol = _____________ Use the conversion factors above to solve the following problems. Show your work using Dimensional Analysis. 9. 3.01 x 1023 atoms of Cu = moles of Cu 12. At STP 1.5 moles of He (g) = L of He (g) 10. 2.0 moles Na = atoms of Na 11. At STP 11.2 L of O2(g) = moles O2(g) 13. 2.20 moles of Sn = grams of Sn 14. 28 grams of C = moles of C Dimensional Analysis 15. How many gallons of soft drink are there in a 2.0L bottle? Fact: 1 gallon ≈ 3.785 L. 16. The density of water at room temperature (25°C) is 0.9970 g/cm3. How many pounds does the water in a full 5.00 gallon pail weigh? Facts: 1 cm3 = 1 mL, 1 gal ≈ 3.785 L, 0.453 kg ≈ 1.0 lb. Scientific notation Write the following in standard notation. 17. A) 2.71 x 104 B) 6.4 x 10–3 Write the following in scientific notation. 18. A) 2,687 4 mL B) 0.012654 Perform the following calculations, answering in proper scientific notation (if appropriate) with the correct number if significant figures. A. (6.02 x 1023) x (8.65 x 104) B) 7.85 x 1026 6.02 x 1023 Significant Figures How many sig figs does each of the following measurements have? 19. 7.991 x 10-10 g____ 21. 0.00030 hL _____ 22. 890 kg ______ Perform the following calculations, answer with the correct units and number of sig figs. 23. A) 86 m/s x 32.421 s = ___________ B) 2.11 x 103 g / 340 mL = __________ Describe each scenario in terms of both precision and accuracy: 24. A basketball player attempts five shots and hits the front of the rim each time. 25. A basketball player attempts five shots and makes it each time. SWISH! 26. A basketball player attempts five shots. He hits the rim three times and makes it twice. 27. A basketball player attempts one shot and makes it. Percent Error and Uncertainty: 28. A student measures using an electronic balance the mass of a samples of salt as 43.21 g +/- 0.02 g. How many significant figures are in this measurement? What is the uncertain digit? What factor affects the certainty of this measurement? 29. The theoretical mass of the above sample of salt is found to be 45.00 g. Determine the percent error in the student’s measurement. Density & Graphing 30. Sketch a graph that shows the density of a substance. Make sure you label the axes appropriately. What are the units of density? 31. The reason that oil floats on top of vinegar in salad dressing is that oil is __________ dense than vinegar. Classification of matter: 32. Classify each as a homogeneous mixture, a heterogeneous mixture, an element or a compound. Also indicate which lab technique(s) could be used to separate the mixtures (distillation, evaporation, or filtration). Matter Classification Possible separation techniques (mixtures only) Water and alcohol (alcohol’s BP = 195oC) Gatorade butane (C4H10) a quartz crystal (SiO2) gold (Au) Sand and water 33. Give at least one example of each of the following: A pure substance that is an element – A pure substance that is a compound – A homogeneous mixture – A heterogeneous mixture -