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- California
- University of California - Irvine
- Chemistry
- Chemistry 1a
- Arasasingham, R.
- Fundamentals A - Matter and Energy + Signficant Figures

Gianna C.

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Chemical Principles: The Quest for Insight by Atkins and Jones 5th Edition Study Guide by Gigi :) Fundamentals A Matter and Energy Significant Figures Key Concepts: types of properties (physical, chemical, intensive, extensive) the use of density in calculations energy, kinetic and gravitational significant figures the nature of volume the properties and base units of matter Matter ?matter: anything that has mass and takes up space ?substance: a single, pure form of matter ?states of matter: 1. solid: matter retains shape and does not flow 2. liquid: matter is fluid with a well-defined surface, takes the shape of the container it occupies 3. gas: matter is fluid and fills any vessel containing it 4. vapor: the gaseous form of a substance that is normally solid or liquid (water vapor) Physical Properties ?physical property: a characteristic of a substance that can be observed or measured without changing the substances' identity 1. melting point 2. boiling point 3. color 4. mass 5. temperature 6. color 7. state (solid, liquid, or gas) 8. density ?physical change: the identity of the substance does not change, only its physical properties 1. melting 2. freezing 3. boiling 4. crystallization 5. sublimation (from solid directly to gas) 6. deposition (from gas directly to solid Chemical Properties ?chemical property: any of the properties of matter that may only be observed and measured by performing a chemical change or reaction 1. reactivity with other chemicals 2. toxicity 3. flammability ?chemical change: the process by which a substance is transformed into a different substance Physical Quantities: ?SI Units are internationally accepted 1. meter ? length 2. kilogram ? mass 3. second ? time 4. temperature ? Kelvin (not ?degrees Kelvin?) 5. electric current ? ampere 6. amount of substance ? mole 7. luminous intensity ? candela ?Prefixes: 1. centi ? 1/100 (centimeter = 1/100 m) 2. milli ? 1/1000 (milliliter = 1/1000 L) 3. kilo ? 1000 (kilogram = 1000 g) ?derived units are used to express more complicated properties 1. volume (V) ? meters cubed (m^3) 2. density ? kilograms/meter^3 3. force ? kg x meters/seconds^2 (Netwon N) 4. energy ? kg x meters^2/seconds^2 (Joule J) ?Common unit conversions: 1. 1.000 kilogram = 2.205 lb (pounds) 2. 1.000 pound = 453.6 g (grams) 3. 1.000 ounce = 28.35 g 4. 1 ft = 30.48 cm 5. 3 ft = yard 6. 1.094 yard = 1.000 meter 7. 1.000 km = 0.6214 miles 8. 1 cm = 0.3937 in 9. 1 in = 2.54 cm 10. 1 min = 60 seconds 11. 1 hour = 3600 s 12. 1 day = 86400 s 13. 1 Liter = 10 cm^3 or 1 decimeter^3 (dm^3) ?conversion factor = units required / units given ?info required = info given / conversion factor ?Example: 1. Snow White is 5.0 feet tall. How tall is she in centimeters? 1. y is Snow White's height 2. conversion factor: 30.48 cm/1.000 ft 3. y = 5.0 x (30.48 cm / 1.000 ft) 4. y = 152.4 cm 5. Snow White is 152.4 cm tall. ?When converting a unit raised to a power (including negative powers), raise the conversion factor to the same power. ?Example: express density of 11600 kilograms/meters^-3 in grams/centimeter^-3 1. 1 kg = 10^3 g and 1 cm = 10^2 m 2. Density = 11600 kg/m^3 x (10^3 g/1 kg) x (1 cm/10^-2 m)^-3 3. 11600 kg/m^3 x (10^3 g/1 kg) x (10^-6 m^3/1cm^3) 1. REMINDER: because the exponent is negative, the numerator and denominator of the expression are switched 4. 11.6 g/cm^3 Intensive and Extensive Properties ?intensive property: a property independent of the size of the sample of a particular substances 1. temperature 2. density 3. hardness 4. melting point 5. boiling point 6. malleability 7. ductility (ability of a solid to deform under tensile stress) 8. viscosity (ability to deform under compressive stress) ?extensive property: a property dependent of the size of a sample 1. energy 2. mass 3. volume 4. weight 5. number of moles 6. electrical charge 7. length ?density = mass / volume (d = m/V) ?density of a substance is independent of the size of the sample because the ratio of mass to volume remains the same ?It is usually given in g/cm^3 ?most properties depend on the state of matter and conditions such as temperature and pressure ?Example: The density of gold is 19.30 g/cm^3 What is the volume occupied by 5.0 g of gold? 1. V = m/d 2. V = 5.0 g/19.30 g/cm^3 3. V = 5.0/19.30 cm^3 4. V = 0.25 cm^3 Significant Figures ?the number of significant figures is the number of digits in a value that can be justified by the data. ?Rules for identifying sig figs: 1. any nonzero digits (1 to 9) are significant (example: 9875 has 4 sig figs) 2. any zeroes (regardless of how many) between two significant digits are significant (200004 has 6 sig figs) 3. any zeroes found to the right of both a significant digit and a decimal place are significant (6.00 has 3 sig figs) ?be careful: many texts (and teachers) consider numbers such as 500 to be ambiguous examples. How to avoid ambiguous zeroes: 1. use scientific notation (5.00 x 10^2 has 3 sig figs) 2. place a zero after the last zero to show significance (500. shows 3 sig figs) 3. place a bar over the final zero to show significance ?Rules for determining number of sig figs in a given operation: 1. Addition and subtraction 1. Answer must show the same number of decimal places as the measurement in the problem with the least number of decimal places 2. Example: 12.3 (3 sig figs) + 1.302938 = 13.6 (3 sig figs) 3. Multiplication and division 1. Answer must show the same number of sig figs as the measurement in the problem with the least number of sig figs 4. Example: 4.333 x 23.4 (3 sig figs) = 101 (3 sig figs) Force ?force (F): an influence that changes the state of motion of an object. An object accelerates when it experiences a force ?acceleration (a): the rate of change of the velocity of an object ?acceleration is proportional to force ?Force = mass x acceleration or F = ma ?Velocity: rate of change of position, has both magnitude and direction ?speed (v): the magnitude of the velocity of an object Energy ?energy: the capacity to do work ?work: motion against an opposing force ?Energy = force x distance ?SI unit for energy is the joule (J). ?1 J = 1 kg x m^2 x s^-2 ?three kinds of energy ? kinetic, potential, and electromagnetic ?Kinetic energy: 1. E(k) = ½mv ^2 2. Example: how much energy does it take to accelerate a biker 70 kg to 20 mph (8.9 m/s) in one direction, starting from rest? 3. ½ x 70 kg x (8.9 m/s)^2 4. 2722.35 J 5. to account for sig figs, represent as kJ 6. 2722/1000 = 2.722 kJ 7. to show 2 sig figs, round to 2.7 kJ ?potential energy: the energy an object has on account of its position in a field of force ?two types of potential energy: gravitational and Coulomb 1. gravitational ? E(p) = mgh 2. m is mass, g is acceleration of free fall, h is height 3. the greater the altitude of an object, the greater its gravitational potential energy ?Coulomb ? to find the potential energy of two charged particles: 1. E= (1/4??0)(q1q2/r) 2. where ?vacuum permitivity? epsilon zero ?0 = 8.854x10-12 C^2/ Jm 3. where C is a ?Coulomb?, the SI unit of charge 4. r is distance 5. Q1 and Q2 are charged particles 6. J is joules, m is meters ?Total energy E = kinetic energy + potential energy Helpful Resources Tutorial on the use of significant figures: http://www.chem.sc.edu/faculty/morgan/resources/sigfigs/index.html Potential Energy on UC Davis ChemWiki: http://chemwiki.ucdavis.edu/Physical_Chemistry/Thermodynamics/State_Functions/Pot ential_Energy The Properties of Matter: http://www.files.chem.vt.edu/RVGS/ACT/notes/Properties_of_Matter.html Converting and Canceling Units: http://www.purplemath.com/modules/units.htm Force and Acceleration: www.Neevia.com, Document Converter Pro, Convert to PDF or Image in batches!

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