Chapter One. Matter and Energy - Chemistry the study of matter and its changes the "central science" Natural Laws

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1 Chapter One Matter and Measurement nivens/curse_list.htm OWL HOMEWORK REQUIRED!!! Matter and Energy - Chemistry the study f matter and its changes the "central science" Matter Anything that has mass and ccupies space. (mass is the amunt f matter, weight is frce f gravitatinal attractin n the mass) Energy The ability t d wrk r transfer heat. Scientific (natural) law A general statement based the bserved behavir f matter t which n exceptins are knwn. 2 Natural Laws Law f Cnservatin f Mass- amunt f matter (mass) is a cnstant under a chemical r physical change Law f Cnservatin f Energy ttal energy in a prcess is fixed, nly cnverted frm ne frm t anther. Law f Cnservatin f Mass-Energy- Universal sum f mass + energy is a cnstant Einstein s Relativity E=mc 2 3

2 States f Matter Slid definite shape and vlume Liquid definite vlume (assumes shape f cntainer) Gas n shape r vlume (expand t fill vlume f cntainer Change f States Heating r cling 4 Chemical and Physical Prperties Chemical Prperties - bserved during a chemical change (change in cmpsitin) rusting r xidatin chemical reactins Physical Prperties bserved as a physical state a cmpund resides in changes f state density, clr, slubility Extensive Prperties - depend n quantity Intensive Prperties - d nt depend n quantity 5 Mixtures, Substances, Cmpunds, and Elements Substance identical cmpsitin and prperties Elements cannt be decmpsed int simpler substances via chemical reactins Elemental symbls fund n peridic chart 6

3 Mixtures, Substances, Cmpunds, and Elements Cmpunds tw r mre elements in a definite rati by mass - can be decmpsed int the cnstituent elements Water hydrgen and xygen Carbn dixide carbn and xygen 7 Mixtures, Substances, Cmpunds, and Elements Mixtures tw r mre substances hmgeneus mixtures same phase Als termed slutins hetergeneus mixtures 8 Math Review and Measurements Make measurements t understand the envirnment Humans sight, taste, smell, sund Limited and biased Use instruments meter sticks, thermmeters, balances Mre accurate and precise All measurements have units METRIC SYSTEM vs. British System 9

4 Units f Measurement Definitins Time Interval r duratin f frward events Mass measure f the quantity f matter in a bdy Weight measure f the gravitatinal attractin fr a bdy (w=mg) 10 Units f Measurement Definitins Length Measure f space in any directin 11 Units f Measurement Vlume Amunt f space ccupied by a system Derived unit, ml r cc, cm 3 12

5 Measurements in Chemistry Quantity Unit Symbl length meter m mass kilgram kg time secnd s current ampere A temperature Kelvin K amt. substance mle ml 13 Measurements in Chemistry Use Metric System Name Symbl Multiplier mega M 10 6 (1,000,000) kil k 10 3 (1,000) deka da 10 deci d 10-1 (0.1) centi c 10-2 (0.01) 14 Measurements in Chemistry Metric Prefixes Name Symbl Multiplier milli m 10-3 (0.001) micr µ 10-6 ( ) nan n 10-9 pic p femt f

6 Units f Measurement Definitins Mass mass is the amunt f matter Weight frce f gravitatinal attractin n mass 16 Units f Measurement Cmmn Cnversin Factrs Length 1 m = inches 2.54 cm = 1 inch Vlume 1 liter = 1.06 qt 1 qt = liter 17 Use f Numbers Exact numbers 1 dzen = 12 things fr example Measured Numbers use rules fr significant figures Use scientific ntatin were pssible Accuracy hw clsely measured values agree with the crrect value Precisin hw clsely individual measurements agree with each ther 18

7 Use f Numbers Significant figures digits believed t be crrect by the persn making the measurement Exact numbers have an infinite number f significant figures = 1 dzen because it is an exact number 19 Significant figures Calculatrs give 8+ numbers Peple estimate numbers differently Scientists develp rules t help yu determine which digits are significant Dictated by the precisin (graduatin) n yur measuring device In the lab, the last significant digit is the digit yu have t estimate 20 Use f Numbers Significant Figures - Rules Nn zer numbers are significant Leading zeres are never significant has three significant figures Imbedded zeres are always significant has five significant figures Trailing zeres may be significant must specify significance by hw the number is written 1300 nails - cunted r weighed? what was the precisin f the measurement? 21

8 Use f Numbers Use scientific ntatin t remve dubt Express answers as pwers f 10 by mving the decimal place right (-) r left (+) x x 10? x x 10? In scientific ntatin, zers are given if they are significant x 10 3 has 4 significant figures 2.40 x 10 3 has? significant figures 22 Use f Numbers -Scientific ntatin fr lgarithms take the lg f 2.40 x 10 3 lg(2.40 x 10 3 ) = Hw many significant figures? -Imbedded zeres are always significant has five significant figures 23 Use f Numbers Multiplicatin & Divisin rule Easier f the tw rules Prduct has the smallest number f significant figures f multipliers x rund ff t

9 Use f Numbers Multiplicatin & Divisin rule Easier f the tw rules Prduct has the smallest number f significant figures f multipliers x rund ff t x rund ff t Use f Numbers Additin & Subtractin rule Mre subtle than the multiplicatin rule Answer cntains smallest decimal place f the addends rund ff t Use f Numbers Additin & Subtractin rule Mre subtle than the multiplicatin rule Answer cntains smallest decimal place f the addends rund ff t rundff t

10 Units f Measurement Cmmn Cnversin Factrs (Equalities) Length 1 m = inches 2.54 cm = 1 inch Vlume 1 liter = 1.06 qt 1 qt = liter See Text and Handut fr mre cnversin factrs 28 Using Cnversin factrs Scientists ften must cnvert between units. Cnversin factrs can be made fr any relatinship. Use knwn equivalence t make a fractin that can be used t cnvert frm ne unit t the ther. Fractin equals 1, s yu are multiplying by 1 29 Factr Label Methd 1 inch = 2.54 cm Rati 1in = cm 2.54cm r 1= 1in Use rati t perfrm a calculatin Units will divide ut. Cnvert 60 in t centimeters 2.54cm 60 inx = cm 1in 30

11 Factr Label Methd 1ft 12 in 1 ft = 12 in becmes r 12 in 1ft Example - Express 9.32 yards in millimeters. 31 Mre practice Express 9.32 yards in millimeters. 1ft 12 in 12 in 1ft 32 Mre Practice 9.32 yd=? mm 3ft 9.32 yd ( ) 1yd 33

12 Mre practice 9.32 yd=? mm 3ft 12in 9.32 yd ( ) ( ) 1yd 1ft 34 Mre Practice 9.32 yd=? mm 3ft 12in 2.54cm 9.32 yd ( ) ( ) ( ) 1yd 1ft 1in 35 Mre Practice 9.32 yd=? mm 3ft 12in 2.54cm 10mm yd ( ) ( ) ( ) ( ) = yd 1ft 1in 1cm mm 36

13 Mre Practice 9.32 yd=? mm 3ft 12in 2.54cm 10mm yd ( ) ( ) ( ) ( ) = yd 1ft 1in 1cm mm 37 Factr Label Methd Example - Express 627 milliliters in gallns. 38 The Unit Factr Methd Example - Express 627 milliliters in gallns.? gal = 627 ml 1L 1.06qt 1gal? gal = 627 ml ( ) ( ) ( ) 1000 ml 1L 4qt? gal = gal gal 39

14 Practice Using yur cnversin handut Cnvert 25 g t lbs Cnvert 1 ml t Liters Cnvert 20 meters t cm 40 Area length x width Area is tw dimensinal thus units must be in squared terms. Example 1-4: Express 2.61 x 10 4 cm 2 in ft 2.? ft = cm ( 1in 2.54 cm ) cmmn mistake 41 Area length x width Area is tw dimensinal thus units must be in squared terms. Example 1-4: Express 2.61 x 10 4 cm 2 in ft in 2? ft = cm ( ) 2.54 cm 42

15 Area length x width Area is tw dimensinal thus units must be in squared terms. Example 1-4: Express 2.61 x 10 4 cm 2 in ft 2. 2? ft = cm ( 1in 2.54 cm 2 ) ( 1 ft 12 in ) 2 43 Vlume length x width x height Vlume is three dimensinal thus units must be in cubic terms this vlume is used in medical measurements--cc Example 1-5: Express 2.61 ft 3 in cm 3.? cm in cm 3 = 2.61 ft ( ) ( ) 1 ft 1 in 3 4 = cm cm 3 44 Percentage Percentage is the parts per hundred f a sample. = (g / g ttal ) X 100% Example - A 335 g sample f re yields 29.5 g f irn. What is the percent f irn in the re? 45

16 Percentage Percentage is the parts per hundred f a sample. Example - A 335 g sample f re yields 29.5 g f irn. What is the percent f irn in the re? grams f irn? % irn= x 100% gramsf re 29.5g Fe = x 100% 335g re = 8.81% 46 Density and Specific Gravity What is density? Density (hw cmpact smething is, mass per unit vlume) density = mass/vlume 47 Density and Specific Gravity Example - Calculate the density f a substance if 742 grams f it ccupies 97.3 cm cm = 1mL 97.3 cm = 97.3 ml density = m V 48

17 Density and Specific Gravity Example - Calculate the density f a substance if 742 grams f it ccupies 97.3 cm cm = 1mL 97.3 cm = 97.3 ml density = m V density = 742 g 97.3 ml density = 7.63 g/ml 49 Density and Specific Gravity Example - Yu need 125 g f a crrsive liquid fr a reactin. What vlume d yu need? liquid s density = 1.32 g/ml 50 Density and Specific Gravity Example - m density= V = V 125 g V= g 1.32 ml m density = 94.7 ml 51

18 Density and Specific Gravity density(substance) Specific Gravity= density(water) Water s density is essentially 1.00 g/ml at rm T. Thus the specific gravity f a substance is very nearly equal t its density. Specific gravity has n units. 52 Density and Specific Gravity Example1-9: A gram piece f chrmium is dipped int a graduated cylinder that cntains 5.00 ml f water. The water level rises t 9.32 ml. What is the specific gravity f chrmium? Vlume f Cr = 9.32 ml ml density f Cr = 4.32 ml = g 4.32 ml 53 Density and Specific Gravity Example1-9: A gram piece f chrmium is dipped int a graduated cylinder that cntains 5.00 ml f water. The water level rises t 9.32 ml. What is the specific gravity f chrmium? g density f Cr = 4.32 ml = g 7.20 g ml ml g 7.20 Specific Gravity f Cr = g 1.00 ml ml =

19 Heat and Temperature Heat and Temperature are nt the same thing T is a measure f the intensity f heat in a bdy 3 cmmn temperature scales - all use water as a reference 55 Heat and Temperature MP water BP water Fahrenheit 32 F 212 F Celsius 0.0 C 100 c C Kelvin 273 K 373 K Bdy temperature 37.0 C, 98.6 F 37.2 C and greater sick 41 C and greater, cnvulsins <28.5 C hypthermia 56 Relatinships f the Three Temperature Scales Kelvin and Centigrade Relatinships K = C+ 273 r C= K

20 Fahrenheit and Centigrade = = = F = 1.8 C+ 32 C = r F Relatinsh ips Example - Cnvert 211 F t degrees Celsius. Example - Express 548 K in Celsius degrees. 58 Heat and Temperature C C Example - Cnvert 211 F t degrees Celsius. = = F = 99.4 C 59 Heat and Temperature Example - Express 548 K in Celsius degrees. C = K 273 C C = =