CHEM 6A Study Guide - Fall 2018, Comprehensive Midterm Notes - Significant Figures, Chemistry, Transfer Of Undertakings Protection Of Employment Regulations 2006
12 Oct 2018
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Department
Course
Professor
CHEM 6A
MIDTERM EXAM
STUDY GUIDE
Fall 2018
CHEM 6A - LECTURE 1 - Chapter 1: Chemistry and Scientific Methods
Chemistry: What did I get Myself Into?
● Chemistry is known as the study of matter and its changes
● Chemistry stems into other sciences, such as physics, biology, or geology
○ Known as the “central science”
○ Other sciences could not exist without chemistry
The Three Learning Levels of Chemistry
Macroscopic - what we see (water in the glass)
Submicroscopic - what we assume because the
human eye cannot see (water molecules)
Symbolic - what we represent it by (H2O, H-O-H,
H:O:H)
https://www.researchgate.net/profile/Dani_Asmadi_Ibrahim/publication/282853867/figure/fig2/A
S:284623880900611@1444871030524/Three-Learning-Levels-of-Chemistry-Johnstone-2006.p
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Professor Bussey, Lecture 1, Slide 3
Scientific Methods
● An iterative (repeating) process
● There is no single scientific method
● How do we know what we know?
○ We present theories, which are
changeable to support new or changing
evidence
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Professor Bussey, Lecture 1, Slide 4
The Law of Conservation of Mass
The Law- matter cannot be created nor destroyed
● Reactions do not change the mass
○ The mass of the reactants=The mass of the product
● Laws tell what is happening, while theories tell why it is happening
○ Ex. the theory of evolution explains why the organisms today are here
● Laws and theories can change as evidence changes
Observation and Measurement
● Qualitative Measurement: General characteristics of the material under study
(descriptions)
○ Color, scent, shape, etc.
● Quantitative Measurement: Result expressed numerically (Must have units!)
○ Mass reactants are 25.3g
○ Mass product is 25.3g
○ Having a number DOES NOT always equal quantitative, the number has to be a
standard measurement
■ Ranking something on a scale from 1-10 is not quantitative
Units and Measurements
● Scientists determine measurements in their observations
○ Dimensions, capacity, quantity
○ Length, mass, volume, density
○ Always has a number and a unit
● All measurements are made relative to standard
○ Standard measurements are agreed upon and the same throughout
○ How good your instrument is determines how close the measurement is to the
standard
● All measurements have uncertainty
Measured Numbers vs. Exact Numbers
● Measured numbers are always uncertain
○ Ex. ALL NUMBERS that are measured
● Exact numbers are infinitely significant
○ Cardinal (counted) values
■ Ex. 2 molecules of H2O, 5 puppies, 4 strands of hair
○ Defined values
■ Ex. 1 in=2.54cm, 1000m=1km
○ Constants
■ Ex. c= 0 m/s3 × 1 8
● Technically measured, but considered to be infinitely significant
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find more resources at oneclass.com
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CHEM 6A Full Course Notes
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Document Summary
Chem 6a - lecture 1 - chapter 1: chemistry and scientific methods. Chemistry is known as the study of matter and its changes. Chemistry stems into other sciences, such as physics, biology, or geology. Other sciences could not exist without chemistry. Macroscopic - what we see (water in the glass) Submicroscopic - what we assume because the human eye cannot see (water molecules) Symbolic - what we represent it by (h2o, h-o-h, We present theories, which are changeable to support new or changing evidence. The law - matter cannot be created nor destroyed. The mass of the reactants=the mass of the product. Laws tell what is happening, while theories tell why it is happening. Ex. the theory of evolution explains why the organisms today are here. Laws and theories can change as evidence changes. Qualitative measurement: general characteristics of the material under study (descriptions) Quantitative measurement: result expressed numerically (must have units!)
