Why should You learn Chemistry? Required Pharmacists Doctors Dentists Chem Engineer, etc. Need it to pass Standardized Exams, Boards, etc. MCAT PCAT DAT OAT, etc Understanding of Nature Drug Design: Manipulate molecules for better medicine Better utilize Energy: Manipulate molecules for better fuels Better understand Life: Biochemistry/Molecular Biology Create better technology

Outline of presentation What is Chemistry? Analytical Chemistry What is in a sample? How much is present? Biochemistry- study of life’s chemistry Inorganic Chemistry- all other elements except carbon Separation Science Organic chemistry- study of carbon compounds Physical Chemistry- study of chemical events based on natural physical phenomenom

Organic Chemistry is the study of compounds that consist of carbon atoms

What is so special about Carbon? Interesting facts: 46 million chemical compounds are known in nature. 99% of them contain carbon (thus organic) Why??

Biochemistry “What are the unique chemical foundations of all life and what is different”

Why should you Learn Biological Chemistry: Drug Design What knowledge is required for drug design? Know structures of protein targets in the body Biochemistry Molecular Biology Know how to manipulate organic molecules to create new compounds with specific properties Organic chemistry Chemical Synthesis Sildenafil

Analytical Chemistry: Science of Chemical Analysis

Careers in Chemistry Chemist/Biochemist Chemical Engineer Industrial Chemist Chemical Technician B.S. (4yr), M.S. (6-7yr), Ph.D. (8-12 yr)

Matter and Measurement By Doba D. Jackson, Ph.D. Associate Professor of Chemistry & Biochemistry Huntingdon College

Matter and Measurement Learning outcomes Describe the different elements and states of matter and their general physical properties Distinguish between different classes of matter. Distinguish between Physical processes and chemical processes Distinguish between exact and uncertainty in numbers, also to express numbers with proper significant figures.

Chemistry and the Elements

The arrangement of the periodic table allows for many properties to be determined by looking at an element’s location.

Elements and the Periodic Table Main Groups columns 1A – 2A (2 groups) columns 3A – 8A (6 groups) Transition Metals: 3B–2B (8 groups, 10 columns) Inner Transition Metals: 14 groups; 3B - 4B lanthanides actinides

Some Chemical Properties of the Elements Property: Any characteristic that can be used to describe or identify matter. Intensive Properties: Do not depend on sample size. temperature melting point Extensive Properties: Do depend on sample size. length volume

Properties of the Elements Physical Properties: Characteristics that do not involve a change in a sample’s chemical makeup. Chemical Properties: Characteristics that do involve a change in a sample’s chemical makeup. Chemical properties and chemical changes are often considered to be synonymous.

Some Chemical Properties of Alkali Metals

Some Chemical Properties of Alkaline Earth Metals

Some Chemical Properties of the Halogens

Some Chemical Properties of the Noble Gases

Some Chemical Properties of the Elements Nonmetals Metals

Some Chemical Properties of the Semimetals (Metaloids) Semimetals are also known as metalloids. Semiconductors and semimetals are not synonymous.

Experimentation and Measurement The U.S. is officially on the metric system, but it’s voluntary. All other units are derived from these fundamental units.

Mass and its Measurement Mass: Amount of matter in an object. Matter: Describes anything with a physical presence—anything you can touch, taste, or smell. Weight: Measures the force with which gravity pulls on an object.

Mass and Its Measurement

Accuracy and Precision Chapter 1: Atoms: Matter and Measurement 6/10/2018 Accuracy and Precision Accuracy: How close to the true value a given measurement is. Percent error Average Precision: How well a number of independent measurements agree with each other. Standard Deviation Least squares fit analysis Copyright © 2010 Pearson Prentice Hall, Inc.

Accuracy and Precision Chapter 1: Atoms: Matter and Measurement 6/10/2018 Accuracy and Precision Mass of a Tennis Ball Measurement # Bathroom Scale Lab Balance Analytical Balance 1 0.0 kg 54.4 g 54.4418 g 2 54.5 g 54.4417 g 3 0.1 kg 54.3 g (average) (0.03 kg) (54.4 g) (54.4418 g) The bathroom scale is not something one would want to use for scientific measurements! It is possible to have good precision and poor accuracy. An instrument improperly calibrated, for example. Poor Accuracy Poor Precision Copyright © 2010 Pearson Prentice Hall, Inc.

Accuracy and Precision Chapter 1: Atoms: Matter and Measurement 6/10/2018 Accuracy and Precision Mass of a Tennis Ball Measurement # Bathroom Scale Lab Balance Analytical Balance 1 0.0 kg 54.4 g 54.4418 g 2 54.5 g 54.4417 g 3 0.1 kg 54.3 g (average) (0.03 kg) (54.4 g) (54.4418 g) The data varies in the first decimal place. While the accuracy is reasonable compared to the analytical balance, the precision is not. Good Accuracy Poor Precision Copyright © 2010 Pearson Prentice Hall, Inc.

Accuracy and Precision Chapter 1: Atoms: Matter and Measurement 6/10/2018 Accuracy and Precision Mass of a Tennis Ball Measurement # Bathroom Scale Lab Balance Analytical Balance 1 0.0 kg 54.4 g 54.4418 g 2 54.5 g 54.4417 g 3 0.1 kg 54.3 g (average) (0.03 kg) (54.4 g) (54.4418 g) The assumption is that the analytical balance is properly calibrated. The data only varies in the fourth decimal place. Good Accuracy Good Precision Copyright © 2010 Pearson Prentice Hall, Inc.

Chapter 1: Atoms: Matter and Measurement Significant Figures 6/10/2018 Rules for counting significant figures: Zeros in the middle of a number are like any other digit; they are always significant. Zeros at the beginning of a number are not significant; they act only to locate the decimal point. Zeros at the end of a number and after the decimal point are always significant. Zeros at the end of a number and after the decimal point may or may not be significant. 4.803 cm 4 SF 0.006 61 g 3 SF (or 6.61 x 10-3 g) Use scientific notation in these cases when reporting the results of calculations. 55.220 K 5 SF 34,200 m 5 SF Copyright © 2010 Pearson Prentice Hall, Inc.

Chapter 1: Atoms: Matter and Measurement 6/10/2018 Rounding Numbers Math rules for keeping track of significant figures: Multiplication or division: The answer can’t have more significant figures than any of the original numbers. 3 SF 11.70 gal 278 mi = 23.8 mi/gal (mpg) 4 SF These rules are approximations that work well. A proper analysis would be a more detailed look at error analysis and is often done in a first quarter physical chemistry class for chemistry majors (or something similar). 3 SF Copyright © 2010 Pearson Prentice Hall, Inc.

Chapter 1: Atoms: Matter and Measurement 6/10/2018 Rounding Numbers Math rules for keeping track of significant figures: Multiplication or division: The answer can’t have more significant figures than any of the original numbers. Addition or subtraction: The answer can’t have more digits to the right of the decimal point than any of the original numbers. 2 decimal places 5 decimal places 3.18 + 0.013 15 3.19 Copyright © 2010 Pearson Prentice Hall, Inc.

Dimensional analysis: converting units from one to another Chapter 1: Atoms: Matter and Measurement 6/10/2018 Dimensional analysis: converting units from one to another 69.5 in 39.37 in 1 m x = 1.77 m starting quantity equivalent quantity A detriment of dimensional analysis is that it’s possible to get the correct answer without a solid understanding of what one is doing. This can be mitigated by doing a conceptual check or determining a “ballpark” solution and comparing it to the answer calculated using dimensional analysis. conversion factor Copyright © 2010 Pearson Prentice Hall, Inc.

Accuracy, Precision, and Significant Figures Significant figures: The total number of digits recorded in a measured or calculated quantity. They come from uncertainty in any measurement. Generally the last digit in a reported measurement is uncertain (estimated). Exact numbers and relationships (7 days in a week, 30 students in a class, etc.) effectively have an infinite number of significant figures.

Accuracy, Precision, and Significant Figures 1 2 4 3 cm 1.7 cm < length < 1.8 cm length = 1.74 cm

Accuracy, Precision, and Significant Figures Rules for counting significant figures (left-to-right): Zeros in the middle of a number are like any other digit; they are always significant. 4.803 cm 4 SF

Accuracy, Precision, and Significant Figures Rules for counting significant figures (left-to-right): Zeros in the middle of a number are like any other digit; they are always significant. Zeros at the beginning of a number are not significant; they act only to locate the decimal point. 0.006 61 g 3 SF (or 6.61 x 10-3 g)

Accuracy, Precision, and Significant Figures Rules for counting significant figures (left-to-right): Zeros in the middle of a number are like any other digit; they are always significant. Zeros at the beginning of a number are not significant; they act only to locate the decimal point. Zeros at the end of a number and after the decimal point are always significant. 55.220 K 5 SF

Accuracy, Precision, and Significant Figures Rules for counting significant figures (left-to-right): Zeros in the middle of a number are like any other digit; they are always significant. Zeros at the beginning of a number are not significant; they act only to locate the decimal point. Zeros at the end of a number and after the decimal point are always significant. Zeros at the end of a number and after the decimal point may or may not be significant. Use scientific notation in these cases when reporting the results of calculations. 34,200 m ? SF

Rounding Numbers Math rules for keeping track of significant figures: Multiplication or division: The answer can’t have more significant figures than any of the original numbers. 3 SF 11.70 gal 278 mi = 23.8 mi/gal (mpg) 4 SF These rules are approximations that work well. A proper analysis would be a more detailed look at error analysis and is often done in a first quarter physical chemistry class for chemistry majors (or something similar). 3 SF

Rounding Numbers Math rules for keeping track of significant figures: Multiplication or division: The answer can’t have more significant figures than any of the original numbers. Addition or subtraction: The answer can’t have more digits to the right of the decimal point than any of the original numbers. 2 decimal places 5 decimal places 3.18 + 0.013 15 3.19

Rounding Numbers Rules for rounding off numbers: If the first digit you remove is less than 5, round down by dropping it and all following digits. 5.664 525 = 5.66

Rounding Numbers Rules for rounding off numbers: If the first digit you remove is less than 5, round down by dropping it and all following digits. If the first digit you remove is 6 or greater, round up by adding 1 to the digit on the left. 5.664 525 = 5.7

Rounding Numbers Rules for rounding off numbers: If the first digit you remove is less than 5, round down by dropping it and all following digits. If the first digit you remove is 6 or greater, round up by adding 1 to the digit on the left. If the first digit you remove is 5 and there are more nonzero digits following, round up. Books sometimes use different rules for this one. 5.664 525 = 5.665

Rounding Numbers Rules for rounding off numbers: If the first digit you remove is less than 5, round down by dropping it and all following digits. If the first digit you remove is 6 or greater, round up by adding 1 to the digit on the left. If the first digit you remove is 5 and there are more nonzero digits following, round up. If the digit you remove is a 5 with nothing following, round down. If there were zeros following that last 5, the rule is the same. 5.664 525 = 5.664 52

Calculations: Converting from One Unit to Another Dimensional analysis: A method that uses a conversion factor to convert a quantity expressed with one unit to an equivalent quantity with a different unit. Conversion factor: States the relationship between two different units. original quantity x conversion factor = equivalent quantity

Calculations: Converting from One Unit to Another Relationship: 1 m = 39.37 in 39.37 in 1 m 1 m 39.37 in Conversion factor: or converts in to m converts m to in

Calculations: Converting from One Unit to Another Incorrect Method 69.5 in 1 m 39.37 in x = 2740 in2/m starting quantity ?? A strength of dimensional analysis is that it makes it easy to verify the units of the answer. conversion factor

Calculations: Converting from One Unit to Another Correct Method 69.5 in 39.37 in 1 m x = 1.77 m starting quantity equivalent quantity A detriment of dimensional analysis is that it’s possible to get the correct answer without a solid understanding of what one is doing. This can be mitigated by doing a conceptual check or determining a “ballpark” solution and comparing it to the answer calculated using dimensional analysis. conversion factor