Chem chapters 1 - 3 Williams

Introduction to Chemistry, Properties of Matter, and Scientific Measurements

types of chemistry

organic, inorganic, analytical, biochemistry, pure, physical

organic chemistry

the study of all chemicals containing carbon

inorganic chemistry

study of chemicals not containing carbon

analytical chemistry

the field of chemistry that is concerned with the composition of matter

biochemistry

field of study concerned with the chemistry of living organisms

pure chemistry

the pursuit of chemical knowledge for its own sake

physical chemistry

deals with the mechanism, rate, and energy transfer that occurs when matter undergoes change

independent variable

what you are testing/controlling

dependent variable

the result of the change in the independent variable

hypothesis

a question you want to support

theory

a hypothesis that has been tested multiple times and has yet to be disproven

law

theory that has been around long enough and tested many times and has not been disproven

problem solving procedure

1. identify and analyze the problem, what is known and unknown - make a plan for getting from known to unknown
2. calculate for the unknown
3. evaluate/check your answer. does it make sense? express with correct units and number of sig figs

matter

anything that has mass and volume

extensive v.s. intensive property

extensive: depends on amount of matter
intensive: depends on type of matter

substance

material that has uniform and definite composition

physical property

quality or condition of a substance

states of matter

solid: uniform distribution of matter - particles in fixed positions, definite volumes
liquid: particles closer together, no definitive position - move baed on container it is stored in
gas: random, spread out positioning of particles - no interaction, expands to fill container - compressible

physical change

does not change composition or properties of a substance
ex. melting ice

chemical change

changes composition or properties of substance
ex. burning paper

mixture

a physical blend of two or more substances
ex. coffee, ice and water

heterogenous v.s. homogenous mixtures

heterogenous: contains two or more phases that you can easily see
ex.what's in a taco
hmomogenous: contains only one phase - cannot see other phases
ex. air, detergent

separating mixtures

using different physical properties of substances: separation, filtration, distillation

elements

simplest form of matter w/unique properties. it cannot be chemically broken down

compound

contains two or more different elements. it can be chemically broken down

symbols and formulas of elements

chem. symbols. first letter always capitalized. second letter lower case if there is one. some element names based on latin or local words.

elements existing diatomically

Hydrogen, Nitrogen, Oxygen, Flourine, Bromine, Iodine, Chlorine

periodic table

arranged by atomic number (protons)
groups - columns (vertical)
periods - rows (horizontal)

reactant, product, precipitate

reactant is what comes before and what reacts to make product (left)
product is what is made by reactant (right)
precipitate is the products that form a solid

does the chemical formula of an element tell you the structure of it?

no (CO2 - O = C = O)

law of conservation of mass

all chemical changes must conserve matter. the number and type of elements in the reactant side must equal the number and type of elements on the product side of the reaction.

what do measurements include

numerical value (magnitude) and measurement unit (context) - math can be applied to all measurement units but units must be compatible

numerical formats of measurements

decimal, scientific notation, and ratio

precision vs accuracy

precision: getting the same value each time something is measured
accuracy: how close your measurement is to the actual value

error calculations

Error = experimental value - accepted value
Percent error = |error|/accepted value x 100%
Percent standard deviation error = std. dev/mean value x 100%
Percent range error = max value - min value/mean value x 100%

significant figures

known = significant, estimate = error of measurement
- any nonzero digit is significant
- trailing and leading zeroes are not significant but trailing zeroes after a decimal point are significant
ex. 7030 m = 7.03 x 103 - 3 sig figs
0.11040 s - 5 sig figs

uncertainty

difference between smallest measurements and divide by two (like the uncertainty on a rule with the smallest measurement being 1mm - 0.001/2 = 0.0005)

rounding rules

Method one: round up values ≥ 5
Method two: round up values w/ a 5 to the adjacent even value

addition and subtraction

Convert measurements so that they are all the same unit
The value with the fewest decimal places defines how many decimal places can be in the answer
ex. 12.52 m + 349.0 m + 8.24 m = 369.76 m = 369.8 m (nothing to do w sig figs)

multiplication and division

Determine which measurement has the fewest sig figs
Answer must be expressed in that number of sig figs
Round value if necessary
7.55 m x 0.34 m = 2.567 m2 = 2.6 m2

SI units

Base or fundamental units are based upon a human definition
Derived units are based upon fundamental units

other measurement systems

Imperial (stone, hand)
US (foot, pound)
cgs (centimeter - gram - second)

SI base units

(Quantity, base unit, symbol)
length, meter, m
temperature, Kelvin, K
time, second, s
mass, gram, g
electric current, ampere, A
luminous intensity, candela, cd
amount of substance, mole, mol

metric prefixes

Prefixes always precede a measurement unit
kilo = 10^3, centi = 10^-2, milli = 10^-3, micro = 10^-6, nano = 10^-9

derived measurement units

volume = lwh = m^3 = derived from a base unit, meters
1g = 1mL = 1cm^3

examples of other derived units

km/hr, m/s
Atmosphere kilopascal (Pa)
Joule (J)
Watt (W)
Newton: kg x m/s/s

temperature scales

The temperature is the measurement of the average velocity of the particles being measured

celsius to kelvin

chemistry uses both - kelvin is not measured in degrees. (necessary to convert)
c = K - 273, K = c + 273

unit conversions

When dealing with measurements the units need to be modified to carry out the necessary analysis, so conversion factors must be generated

density

unique to every substance/element. a pure substance is an element.

distillation

use of heat to separate the components of a liquid and/or gas

filtration

filtration is the separation of solids from a fluid (either a gas or a liquid) by allowing the fluid to pass through a filter

separation

a method that converts a mixture or a solution of chemical substances into two or more distinct product mixtures

Celsius to Fahrenheit and vice versa

C = (F - 32)5/9
F = (C x 9/5) + 32