general chemistry - florida state universityzakarian/az_personal_web_cz/chm1050... · general...
TRANSCRIPT
General ChemistryIntroduction: Definitions and Measurements
CHM1050_3
*Aspartame – NutraSweet™. 5 times sweeter than sugar.
Chemistry is the study of matter, its properties, as well as its transformations and energy
associated with those transformations.
CHM1050_3
Chemistry: A Definition
CHM1050_3
Nobody fully knows what it really is. Here’s asmuch as we could surmise:
• Matter is the “stuff” around us
• The “stuff” is made of molecules and atoms
Structure of Matter
CHM1050_3
Individual Substances,or Compounds:
• identical molecules
• well-defined set of physical and chemical properties
Mixtures:
• different molecules and other particles
• physical and other properties depend on relative amounts of substances in them
Composition of Matter
CHM1050_3
SOLIDfixed volumefixed shape
LIQUIDfixed volume
changing shape
GASchanging volumechanging shape
solid salt crystal
NaCl liquid water molecules
molecules of a gas
Three States of Matter
CHM1050_3
Examples of physicalproperties:
Melting pointBoiling pointDensityPlasticityConductivityColor
Examples of chemicalproperties:
CorrosivenessFlammabilityOther types of
reactivity
Properties: physical and chemical
CHM1050_3
extensive: depend on the amount of substance presentintensive: independent of the amount of substance present
Examples of physical properties and parameters:Mass, volume - extensiveMelting point - intensiveBoiling point - intensiveDensityPlasticityConductivityColor
Physical properties
CHM1050_3
extensive: depend on the amount of substance presentintensive: independent of the amount of substance present
Examples of physical properties and parameters:Mass, volume - extensiveMelting point - intensiveBoiling point - intensiveDensity - intensivePlasticity - intensiveConductivity - intensiveColor - intensive
Physical properties
CHM1050_3
physical properties:
Color: bluish pale grey metallicMelting point: 419.53 oC [787.15 oF]
Boiling point: 907 oC [1665 oF]
Density: 7140 kg/m3
Resistivity: 5.9.10-8 W m
some chemical properties:
tarnishes in the air very slowly dissolves in dilute acid reacts violently with sulfur (picture above)
Properties: example
Zinc
CHM1050_3
Physics: Potential Energyposition of an object
Kinetic Energymotion of an object
Chemistry:Chemical potential energy:
energy stored in the molecules and is determinedby their structure (example: fossil fuels).
Energy: chemical potential energy
CHM1050_3
Dawn of humanity: Trial and Error
Modern Science: Observation → Hypothesis → Experiment → Theory
(“educated” trial/error)
A little bit about the scientific method
CHM1050_3
Year 1960, International System of Units, SI units
Measurements
SI Fundamental Units of Measurement
Physical Quantity (Dimension) Unit Name Abbreviation
Mass kilogram kgLength meter mTime second sTemperature kelvin KElectric Current ampere AAmount of substance mole molLuminous intensity candela cd
CHM1050_3
LengthSI: 1 meter (m) = 1.094 yard
1 cm = 10-2 m = 0.3937 in1 inch = 2.54 cm
VolumeSI: 1 m3
1 L (liter) = 10-3 m3 = 1 dm3
1 mL = 1 cm3 = 10-3 L = 10-3 dm3
1 L = 1.057 quart1 fluid ounce = 29.57 mL
Measurements Useful in Chemistry
CHM1050_3
The volume of an irregularly shaped solid can bedetermined by the volume of water it displaces.
Volume: Practice Exercise
Volume (mL) = volume after - volume before = 21.5 mL - 23.0 mL = 1.5 mL (cm3)
Volume (fl. oz.) =
1 fl. oz = 29.57 mL
CHM1050_3
The volume of an irregularly shaped solid can bedetermined by the volume of water it displaces.
Volume: Practice Exercise
Volume (mL) = volume after - volume before = 21.5 mL - 23.0 mL = 1.5 mL (cm3)
Volume (fl. oz.) =
1 fl. oz = 29.57 mL
1 29.57
fl. oz = 1 mL
CHM1050_3
The volume of an irregularly shaped solid can bedetermined by the volume of water it displaces.
Volume: Practice Exercise
Volume (mL) = volume after - volume before = 21.5 mL - 23.0 mL = 1.5 mL (cm3)
Volume (fl. oz.) = 1.5 mL × = 0.05 fl oz1 fl oz29.57 ml
CHM1050_3
Measurements Useful in Chemistry
MassSI: 1 kilogram (kg) = 2.205 lb
1 gram (g) = 10-3 kg
Density (d) !SI: 1 kg/m3 = g/cm3 = g/mL
density = mass volume
CHM1050_3
Measurements Useful in Chemistry
Temperature
CHM1050_3
Measurements Useful in Chemistry
Temperature
T ºC = (T ºF - 32) 59
T ºF = T ºC + 32 95
T ºC = T K + 273
CHM1050_3
Temperature: Practice Exercise
The highest daytime temperature recorded on Mars is 27 ºC,while the average night time temperature is about -107 ºC.What’s the temperature in Fahrenheit, is it comfortable forhumans?
95
T ºF = T ºC + 32
CHM1050_3
Temperature: Practice Exercise
T ºF = ×27ºC + 32 = 81 ºF 95Daytime:
The highest daytime temperature recorded on Mars is 27 ºC,while the average night time temperature is about -107 ºC.What’s the temperature in Fahrenheit, is it comfortable forhumans?
95
T ºF = T ºC + 32
CHM1050_3
Temperature: Practice Exercise
T ºF = ×27ºC + 32 = 81 ºF 95
T ºF = ×(-107ºC) + 32 = -161 ºF 95
Daytime:
Night time:
The highest daytime temperature recorded on Mars is 27 ºC,while the average night time temperature is about -107 ºC.What’s the temperature in Fahrenheit, is it comfortable forhumans?
95
T ºF = T ºC + 32
CHM1050_3
Time
SI standard unit: second (s)
1 hour = 60 min1 min = 60 s
Measurements Useful in Chemistry
CHM1050_3
• All devices have limited sensitivity → uncertainty in measurement
2.84 ± 0.01 g; 82740 ± 5 years
• “we always estimate the rightmost digit”
• significant figures: all figures we record in measurement
2.84 g; 82740 years
Significant Figures/Uncertainty inMeasurement
CHM1050_3
0.0009039 m 9.1 × 10-5 s 400 L 400. L 400.0 L
Which Figures Are Significant?
all non-zero digits are significant
CHM1050_3
0.0009039 m 9.1 × 10-5 s 400 L 400. L 400.0 L
4 sf
Which Figures Are Significant?
CHM1050_3
0.0009039 m 9.1 × 10-5 s 400 L 400. L 400.0 L
4 sf 2 sf
Which Figures Are Significant?
CHM1050_3
0.0009039 m 9.1 × 10-5 s 400 L 400. L 400.0 L
4 sf 2 sf 1 sf
Which Figures Are Significant?
CHM1050_3
0.0009039 m 9.1 × 10-5 s 400 L 400. L 400.0 L
4 sf 2 sf 1 sf 3 sf
Which Figures Are Significant?
CHM1050_3
0.0009039 m 9.1 × 10-5 s 400 L 400. L 400.0 L
4 sf 2 sf 1 sf 3 sf 4 sf
Which Figures Are Significant?
CHM1050_3
1. multiplication and division: the answer has the samenumber of sf as the measurement with the fewest sf:
Volume (cm3) = 1.23542 cm × 1.0365 cm × 3 cm = 4 cm3
2. addition and subtraction: the answer has the samenumber of decimal places as the measurement with thefewest number of decimal places.
Volume (mL) = 34.1 ml + 4.943567238956 mL = 39.0 mL
Some Math
CHM1050_3
Properties: physical/chemical
States of matter: volume/shape
SI standard units of measurement
Measurements: significant figures/uncertainty
Chapter 1: Overview
CHM1050_3
Chapter 1: Overview
mass volumedensity =
T ºC = (T ºF - 32)
T ºF = T ºC + 32 95
59
CHM1050_3
Practice ExercisesAccording to the ancient greek legend, Archimedes discovered thedisplacement method of density determination while bathing andused it to find the composition of the king’s crown. If a crownweighing 4 lb 13 oz displaces 186 mL of water, is it made of puregold (d = 19.2 g/cm3)?
CHM1050_3
Practice Exercises
mass volumedensity = 1 kg = 1000 g = 2.205 lb; 1 oz = 28.3 g
According to the ancient greek legend, Archimedes discovered thedisplacement method of density determination while bathing andused it to find the composition of the king’s crown. If a crownweighing 4 lb 13 oz displaces 186 mL of water, is it made of puregold (d = 19.2 g/cm3)?
CHM1050_3
Practice Exercises
mass volumedensity = 1 kg = 1000 g = 2.205 lb; 1 oz = 28.3 g
mass = 4 lb × 1000 g 2.205 lb + 13 × 28.3 g/oz = 2182 g
(1814.1 g) (367.9 g)
According to the ancient greek legend, Archimedes discovered thedisplacement method of density determination while bathing andused it to find the composition of the king’s crown. If a crownweighing 4 lb 13 oz displaces 186 mL of water, is it made of puregold (d = 19.2 g/cm3)?
CHM1050_3
Practice ExercisesAccording to the ancient greek legend, Archimedes discovered thedisplacement method of density determination while bathing andused it to find the composition of the king’s crown. If a crownweighing 4 lb 13 oz displaces 186 mL of water, is it made of puregold (d = 19.2 g/cm3)?
mass volumedensity = 1 kg = 1000 g = 2.205 lb; 1 oz = 28.3 g
mass = 4 lb × 1000 g 2.205 lb + 13 × 28.3 g/oz = 2182 g
d = 2182 g/186 mL = 11.7 g/mL = 11.7 g/cm3
CHM1050_3
Practice Exercises
mass volumedensity =
Copper coins actually contain very little copper. If a coin is97.3% zinc (d = 7.14 g/cm3) and 2.7% copper (d = 8.95 g/cm3) bymass, what is its density?
CHM1050_3
Practice Exercises
mass volumedensity =
Copper coins actually contain very little copper. If a coin is97.3% zinc (d = 7.14 g/cm3) and 2.7% copper (d = 8.95 g/cm3) bymass, what is its density?
mass (Cu) + mass (Zn) volume (Cu) + volume (Zn)=
CHM1050_3
Practice Exercises
mass volumedensity =
Copper coins actually contain very little copper. If a coin is97.3% zinc (d = 7.14 g/cm3) and 2.7% copper (d = 8.95 g/cm3) bymass, what is its density?
mass (Cu) + mass (Zn) volume (Cu) + volume (Zn)=
Volume (Zn) = 0.973 g 7.14 g/cm3 = 0.136 cm3
Volume (Cu) = 0.027 g 8.95 g/cm3 = 0.003 cm3
CHM1050_3
Practice Exercises
mass volumedensity =
Copper coins actually contain very little copper. If a coin is97.3% zinc (d = 7.14 g/cm3) and 2.7% copper (d = 8.95 g/cm3) bymass, what is its density?
mass (Cu) + mass (Zn) volume (Cu) + volume (Zn)=
Volume (Zn) = 0.973 g 7.14 g/cm3 = 0.136 cm3
Volume (Cu) = 0.027 g 8.95 g/cm3 = 0.003 cm3
density = 1.000 g 0.139 cm3 = 7.19 g/cm3