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Chemistry Unit 1 Cheat Sheet by

Most important things out of unit 1

The nature of chemistry

 

Nature of Chemistry

Chemistry
Study of substances that make up the world and the changes they undergo
Pseydo­science
Process inv. the collection of info that is supported by belief or opin­ion
Science
Process inv. the collection of info that is supported by evid­ence
Science is system­atic, inv. collection of info and ideas, inv. obs. and experi­men­tation, supp. by evidence
Science relies on process, is objective, is updated constantly
Pseudo­science lacks process, is subject, is resistant to new info (i.e. flat earters..)
Scientific inquiry is the process of using obs, invest­iga­tions, and exp. to learn about natural phenomena -> any testable questions about obs., importance on creativity

Formul­ating Scientific Questions

Scientific question
Based on obs. and is test­able
Most Q are based on obs.
What is that? Why? How does it work? I wonder why..
A good one
narrow focus, unknown answer, addresses gap in knowledge, leads to a hypothesis that can be tested
Non scientific question
based on supern­atural, opinion, rely on moral or social values

Scientific methods

Dependent variable
Variable that is changed by another variable
Indepe­ndent variable
The variable that you change
Qualit­ative
Obs/data that is not measured on number­s/p­recise measur­ements
Quanti­tative
Obs/data based on number­s/p­recise measur­ements
Sc. Inquiry
Process of using obs, inv., and exp. to learn about natural phenomena
Conclusion
Summary of the results
Controlled exp.
an exp. in which one variable is changed
Control sample
Sample in a controlled exp. with variables that don't change
Exp. sample
sample in a controlled exp. in which one variable changes
Models
Simple, idea, picture, equation, method, diagram -> visual­izing exp. results
Writing a lab report
Questi­on/­Hyp­othesis -> materials -> procedure -> result­s/data -> analysis -> conclusion
 

Research in Science

Skepticism
Open minded knowledge in a certain area may be uncertain
Bias
Point of view influenced by opinion
Scientific census
General agreement along scientists on an idea
How to develop sc. census?
Commun­ica­tion! Public­ations (peer-­rev­iewed), meetin­gs/­con­fer­ences, discuss findings (perso­n/o­nline)
Databases
Pubmed, NCBI, NHI, Google scholar

Hypoth­esis, Theory, and Law

Hypothesis
Testable expl. of a sc. problem based on research and obs. (if/then). Must be testable, suppor­ted­/re­futed by data
Theory
Hypothesis or a group of rel. hypothesis as true based on obs. and repetitive exp., must be testable, req. many exp. and confirmed data to overtu­rn/­modify, can be used for predic­tions or explan­ations
Law
Statement of facts generally accepted to be true, describes relati­onships in nature, but does not prov. explan­ation; can be used to predict events­/exp. results, support. by all obs. and data, doesn't
How to work with a Hypoth­esis?
Attempt to explain an obs. or answer a Q -> test it -> if support, then data will agree with it -> if refute, then data will not agree, redo procedure or hypothesis -> continue evaluating data
Dalton's Atomic Theory
all matter is comp. of atoms, atoms cannot be made/d­est­royed during chemical reactions, all atoms of an element are identical, different elements have diff. kinds of atoms, chemical reactions occur through rearra­ngement of atoms
Atomic Theory
Explains law of conser­vation of mass
Reprod­uci­bility leads to reliab­ility
Theory must be supported by all evidence, other scientists should get similar results, all experiment must be reprod­ucible
 

Safety in Science

MSDS (material safety data sheet)
Describes proper­ties, handling, and emergency procedures of a substance
General safety practices
Avoid lose clothe­s/hair, wear long sleeve­s/close toed shoes, do not drink/­eat­/chew gum, no jewelry, avoid contacts if possible, avoid clutter in lab
Handling chemic­als­/eq­uipment
Use tongs/­mitts for hot objects, label all contai­ners, inspect equipment before use, dispose of all substances approp­riately
PPE (personal protective equipment)
Eyes/face: safety goggle­s/s­hield, skin/c­lot­hing: lab coat/a­pron, hands: gloves
Emergency equipment
Fire exting­uisher, eye wash, safety shower, first-aid kit
Chemistry glass ware
Beaker, flask, test tubes, graduated cylinder
Handling glass ware
check for breaks­/chips, use tongs/­holders
Heating devices
Bunsen brenne­r/a­lcohol burner, hot plate
Use of chemicals
Use clear/­acc­urate labels, do not taste/­sme­ll/­touch chemicals, use pipettes to transfer liquids, do not put liquids back into storage container, refer to MSDS for storag­e/d­isp­osa­l/h­andling
Accident
Stay calm, report, avoid danger, spill kit, help injured
Cuts from broken glassware
apply pressu­re/­flush
Chemical burns/­irr­ita­tio­ns/heat burns
remove heat source/put out fire
Inhalation of toxic chemicals
Get fresh air/report
Chemicals in eyes
Eye wash (10-15 mins), report
 

Tools and Technology in chem

Balance
Measure mass
Beaker
Holds liquids
Buret
Used to deliver specific volume, i.e. titrate volumes
Degrees Celsius
Fahrenheit - 30 : 2 = ~ x C
Graduated cylinder
Measure volume of liquid
SI
Intern­ational system of units, standard set of units used by all scientists
Kelvin
SI unit for temper­ature in science, 0 C = -273.15 K
Kilogram
SI Unit for mass
Liter
SI unit for volume
Meter
SI unit for distance

Metric system

Common SI units

Metric conversion example

Collecting and organizing data

inference
logical conclusion made from observ­ation
Qualit­ative data
non-nu­mer­ical, descri­ptive - describes categories or charac­ter­istics of things
Quanti­tative data
numerical data that can be measured, data that is easy to analyze over graph or table, has units, always numbers
Charts
Used for qualit­ative data
Tables
Used for numerical data set in columns and rows
Graphs
Bar/li­ne/pie, display data for analysis
Labels
for all parts of charts, tables, and graphs

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