Chem 106 Practical Everyday Chemistry Dr. Ron Rusay Diablo Valley College Spring 2004

Chem 106’s Homepage

Science, Mathematics, Chemistry & the World Around You  What is science?…. What is chemistry?  VOCABULARY: Key Terms/ Communication  Comparisons and Conversions : Ratios, Percent, Density  Mathematics / Arithmetic: Powers of Ten, Scientific Notation  Measurement & Units: (metric)  Matter : Classification & Properties © Copyright R.J. Rusay

Observation: Perception Can more than one observation be correct?Can more than one observation be correct? What do you see?What do you see? Science relies on observation.

What might this be? Why is this important? Would you colonize Mars?

Science: Problem Solving Can you connect all of the dots with four straight lines without taking a pen or pencil from the surface?

Science: Problem Solving

Can there be more than one solution for the same problem? Of Course!

Ancient Science: Greeks, Chinese, Arabs, Persians What is the stuff around us? How do things work?

Science is driven by asking questions & making predictions, but where does science end and philosophy & speculation begin?Science is driven by asking questions & making predictions, but where does science end and philosophy & speculation begin? The Scientific Method is a way to develop answers and predict outcomes, but it is not foolproof!The Scientific Method is a way to develop answers and predict outcomes, but it is not foolproof!

Some Possible Steps in the Scientific Method  1. Observations ---- qualitative ---- quantitative  2. Formulating hypotheses ----possible explanation for the observation  3. Gathering information & Performing experiments ----gather new information to test whether the hypothesis is valid

Chemistry is the Study of Matter  Observed in all of its forms & behaviors.  Sub-categories Organic: carbon Inorganic: non-carbon Organometallic: Organic + Inorganic Analytical: What?, How much?, How pure? Biological / Biochemistry: living organisms Physical: energy, changes, rates Nuclear: the nucleus Environmental: interdisciplinary, eg. Oceanography © Copyright R.J. Rusay Can mean the study of anything and everything! Can matter be observed at all times?

Modern Science & Chemistry Would this motivate you to pursue a career in science/chemistry?Would this motivate you to pursue a career in science/chemistry? Why would this “excite” a scientist, and what does dating have to to with it?Why would this “excite” a scientist, and what does dating have to to with it?

How do we know how old things are ?… like sloth dung Dating! Radiocarbon dating that is. It allows determining the age of biological artifacts like dung up to about 40,000 years old. This method provides an direct measurement of age. How do we determine our own age?How do we determine our own age? Can this work for anyone or any animal that ever lived?Can this work for anyone or any animal that ever lived?

Types of Basic Measurements: for stuff that you can see or sense MASS (weight) LENGTH VOLUME (occupied space) TEMPERATURE TIME Qualitative vs. Quantitative Eg. Qualitative: Old (dung) vs. Young (you?) Quantitative: 38,000 year old (dung) vs. a 19 year old (you?) © Copyright R.J. Rusay

What is the length of the rod? Different measurement tools give different numbers: Which ruler is better? Did the Hubble space telescope use English or metric units in its construction? …..navigating the Mars Climate Orbiter?

Volume (Liquid Measurement Tools)

Relative Temperature Scales Jan. 15, o F Berlin, N.H. o C? K?

Temperature

Very Large & Very Small Stuff Powers of 10 (10 x ) Earth = 12,760,000 meters wide (12.76 x 10 6 ), million meters Plant Cell = meters wide (12.76 x ) (12.76 millionths of a meter)

Detecting stuff we cannot see: the Sense of Smell Models, Theories & Interactions Structure-Odor Relationships Karen J. Rossiter, Chem. Rev., 1996, 96,

Three different smell receptors.

Modeling and Smell Four different molecules fitting the same smell receptor.

Shapes & Interactions: Mirror Images & Smell S-(+)-d- R-(-)-l- S-(+)- carawayR-(-)- spearmint

Representations of Measurements: An example of a relative comparison using length to represent time TIME: 38,000 year old (dung) vs. 20 year old student LENGTH: Use lines to represent the respective ages that can be easily drawn on the classroom’s blackboard. Let 1 inch equal some period of time: 1 yr, 5 yr, 10yr, 100yr, 1000yr. (Select an appropriate one.) 38,000 year old (dung) vs. 20 year old student © Copyright R.J. Rusay 38,000 yrs / 20 yrs = 1900 times

Representations of Measurements An example of a relative comparison using length to represent time TIME: LENGTH; 38,000 year old (dung) vs. 20 year old student 1 in= 1 yr: dung = 38,000 in (> 1/2 mile) - student = 20 in 1 in= 5 yr: dung = 7,600 in (> 2 football fields) - student = 4 in 1 in= 10 yr: dung = 3,800 in (> 100 yds) - student = 2 in 1 in= 100 yr: dung = 380 in ( 31.6 feet) - student = 0.2 in 1 in= 1000 yr: dung = 38 in ( 3.16 feet) - student = 0.02 in © Copyright R.J. Rusay

Representations of Measurements An example of a relative comparison using length to represent time TIME: LENGTH; 38,000 year old (dung) vs. 20 year old student 1 in= 1 yr: dung = 38,000 in (> 1/2 mile) - student = 20 in 1 in= 5 yr: dung = 7,600 in (> 2 football fields) - student = 4 in 1 in= 10 yr: dung = 3,800 in (> 100 yds) - student = 2 in 1 in= 100 yr: dung = 380 in ( 31.6 feet) - student = 0.2 in 1 in= 1000 yr: dung = 38 in ( 3.16 feet) - student = 0.02 in © Copyright R.J. Rusay

Match the years in the second column with choices from the first column B C E I F L K G D A H J

Popcorn & Science How good is it? Expansion Kernel Size Moisture Content cm 3 / g Kernels / 10 g Percent H 2 O How would you experimentally determine these values?

Chemistry in your car: Airbags Count how many words are new to you. A) ZeroB) 1-5C) 6-10D) >10