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These people have not yet passed the safety quiz. Second chance goes till 5 pm T. You will need an 84% to pass. Some Interesting Quantities. Length Volume Mass. Fig 1. 11. Significant Digits Tutorial. Precision and Accuracy
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These people have not yet passed the safety quiz. Second chance goes till 5 pm T. You will need an 84% to pass.
Some Interesting Quantities Length Volume Mass Fig 1. 11
Precision and Accuracy http://ull.chemistry.uakron.edu/genobc/Chapter_01/
How to Solve Chemistry Problems 1) Problem: States all of the information needed to solve the Problem. 2) Plan: Clarify the known and unknown. Suggest the steps needed to find the solution. Develop a “roadmap”solution. 3)Solution: Calculations appear in the same order as outlined. 4) Check: Is the result what you expect or at least in the same order of magnitude! 5) Comment:Additional information as needed.
Conversion Factors : Unity Factors - I Equivalent factors can be turned into conversion factors by dividing one side into the other! 1 mile = 5280 ft or1 = 1 mile / 5280 ft = 5280 ft / 1 mi 1 in = 2.54 cm or1 = 1 in / 2.54 cm = 2.54 cm / 1 in In converting one set of units for another, the one desired is on top in the conversion factor, and the “old” one is canceled out! Convert 29,141 ft into miles! 29,141 ft x 1 mi / 5280 ft = 5. 519 mi
Conversion Factors - II 1.61 km = 1 mi or 1 = 1.61 km / 1 mi Convert 5.519 miles in to kilometers 5.519 mi x 1.61 km / mi = 8.89 km conversions in the metric system are easy, as 1 km = 1000 m and 1 meter (m) = 100 centimeters(cm) and 1 cm = 10 millimeters(mm) Now: Convert into cm and mm! 8.89 km x 1000m / 1 km = 8890 m 8890 m x 100 cm / m = 889000 cm
Derived SI Units Quantity Definition of Quantity SI unit Area Length squared m2 Volume Length cubed m3 Density Mass per unit volume kg/m3 Speed Distance traveled per unit time m/s Acceleration Speed changed per unit time m/s2 Force Mass times acceleration of object kg * m/s2 ( =newton, N) Pressure Force per unit area kg/(ms2) ( = pascal, Pa) Energy Force times distance traveled kg * m2/s2 ( = joule, J)
Conversion Factors - IVmetric volume to metric volume • 1.35 x 109 km3 = volume of world’s oceans What is this volume expressed in liters? conversion factors: 1000 m = 1 km 1000 l = 1 m3 1.35 x 109 km3 x (103 m/1 km )3 x ( 103 l/m3) = 1.35 x 1021 liters
Conversion Factors - V Calculate the mass of 1.00 ft3 of Lead (density=11.4g/ml)? • 1.00 ft3 x (12 in/ft)3 x (2.54 cm/in)3 = • 28,316.84659 cm3 2.83 x 104 cm3 x 11.4 g/cm3 = 322,620.0000 g Ans. = 3.23 x 105 g = 3.23 x 102 kg
Energy Involved in Phase Changes Liberates Energy Gas Boiling Condensation Liquid Melting Freezing Solid Requires Energy
Definitions - II Energy - The capacity to do work! Potential Energy - The energy due to the position of the object.Or Energy from a chemical reaction. Kinetic Energy - The energy due to the motion of the object.
Units of Energy: Calories and Joules 4.84 cal = 1 J 1000 cal = 1 Kcal = 1 Cal (dietary)