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Note Guide 1-1 Measurement Measurement – quantity that has both a number and a unit. EX: 36° Celsius (#) (unit) --measurement is central to science, especially the experimental scientists. so, if its important, we need to be careful and precise --Accuracy vs. PrecisionAccuracy vs. Precision Most people thing these are the same. In chemistry, its not true I tell ya! 1. Accuracy – how close the measure comes to the actual value 2. Precision – how close a series of measurements are to one another in Chem, we want Both!! HOW? -Take your time! Its not a race!
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--Accuracy and Precision Example Good Accuracy Poor Accuracy Poor Accuracy Good Precision Good Precision Poor Precision --Error comparison of the experimental value compared to the accepted value. + Boiling point of water is 100° C accepted value -if we measure, it shows 99.1° C experimental value --if we know both experimental value and accepted value, we can calculate error
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Scientific Notation – used for every large numbers --why use it? It is easier --written as a coefficient and 10 to a raised power EX: 602,000,000,000,000,000,000,000 = 6.02 x 10 23 Coefficient is 6.02 – coefficients have to be equal to 1 or greater and up to 10. How we can calculate it: (white board) 602,000,000,000,000,000,000,000 --rule: move decimal to the left until you get between 1 and 10
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Note Guide 1-2 Chemistry and Review information Chemistry – the study of the composition of matter (anything that occupies space and has mass) and the changes matter undergoes. --affects all aspects of life and most natural events. 5 areas of study: 1.Organic chem – study of all chemicals with carbon in them. 2.Inorganic chem – study of all chemicals without carbon in them. 3.Biochemistry – study of the processes taking place in life 4.Analytical chem – study of the composition of matter 5.Physical chem – area that deals with the mechanism, the rate and the energy transfer occurring when matter changes
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Mixtures – physical blend of two or more componentsMixtures 1. Heterogeneous – composition is not uniform throughout. 2. Homogeneous – composition is uniform throughout --sometimes called a solution Chemical change – change that produces matter with a different composition than the original matter Chemical reaction – once or more substances change into one or more new substances.Chemical reaction --reactant – substance which is present at the start of the reaction. --product – substance produced during the reaction. Clues to chemical change: transfer of energy; change in color, production of gas, or production of a precipitate (solid which settles out of a liquid mixture.
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Conservation of Mass – in any change, mass is conserved (no mass created nor destroyed.Conservation of Mass --mass in = mass out
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What is the study of all chemicals containing carbon? 1.Inorganic Chemistry 2.Analytical Chemistry 3.Organic Chemistry 4.Biochemistry
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The starting substance in a chemical reaction is called 1.Reactant 2.Product 3.Precipitate 4.By-product
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Accuracy is the narrowness of range of measurements. 1.True 2.False
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Noteguide 1-3 Metrics ISI – revised system (METRIC) –based on the multiples of ten. --all scientists around the world use it. WHY? so everyone is on the same page. EX: space/wrong calcs. Basic Unit of Measure LengthMeter (m) MassKilogram (kg) TempKelvin (K) TimeSecond (s) Amt of substanceMole – (mol) Luminous IntensityCandela (cd) Electric currentAmpere (A)
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--prefixes used to give size differences EX: kilogram Kilo = 1000 times bigger than base Centi = 100 times smaller than base Milli = 1000 times smaller than base --Volume (space that matter takes up) -base unit is liter (L) --Mass (how much matter inside -base unit is kilogram -mass and weight are the same, right? WRONG!! weight is the force of gravity on the MASS of the object EX: go to the moon, mass has not changed but weight has due to less gravity. --Temp (how hot or cold and object is) A. Celsius = scale sets freezing of water at 0° and boiling at 100°
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B) Kelvin – sets freezing of water at 273° K and boiling at 373°K --also has absolute zero (last/first spot on the scale) --can convert from kelvin to celsius and vice versa easily K = °C + 273 C = °K - 273 --Unit of Energy (capacity to do work; produce heat) -joule = energy -calorie quantity of heat that raises the temp of 1 gram of pure water by 1°C
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The basic unit of measure for mass is the 1.Kilometer 2.Milligram 3.Kilogram 4.pound
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Which of the following prefix means 100 times smaller than the base unit? 1.Kilo- 2.Centi- 3.Milli- 4.Hecta-
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The kelvin scale sets the boiling point of water at _____K. 1.100° 2.273° 3.373° 4.None of above
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Noteguide 1-4 DensityDensity *What is heavier, a pound of paper or a pound of cement? --only difference is the volume of paper compared to cement. Density = rate of the mass of an object to its volumeDensity D = m / V --when we talk about density, it depends only on the composition of a substance, not the size of the sample --Relationship of density and temp density of substance generally decreases as temp increases note: the volume of a substance changes as the temp. changes DO PRACTICE PROBLEM 3.1 #3 PAGE 69 DO PRACTICE PROBLEM 3.4 16 AND 17 PG 78 DO PRACTICE PROBLEM 3.10 46 AND 47 PG. 91
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