AP Chemistry Exam Question of the Week

1. AP Chemistry Exam Question of the Week Lab safety glasses are NOT needed for which of the following? a). Weighing samples b). Boiling water c). Distilling alcohol d). Pre-lab write-ups e). Titrations

2. Matter Does it really matter?

3. Physical And Chemical Properties • Physical Properties • Density • Malleability • Ductility • Conductivity • Chemical Properties • Kind of chemical changes that material can undergo

4. Physical And Chemical Changes • Physical Changes • Shape • Size • Color • Boiling water or freezing water • Chemical Changes • Change in the identity of the material • Rust

5. Pure Substances vs. Mixtures • Pure Substance • One type of matter • Can be separated into more than one pure substance but only by chemical change • Mixtures • Can be separated into 2 or more pure substances by physical change • 2 types • Heterogeneous • Homogenous

6. Elements and Symbols • Element • Pure substance that consists of only one kind of atom • Examples • Atoms • Basic particles that make up elements • Consists of positive particles called protons, negative particles called electrons and neutral particles called neutrons • Ions • Protons and electrons = each other in the atom the atom has a neutral charge • When protons and electrons are unbalanced atom is charged and is considered an ion • Molecules • Atoms by themselves in their natural state are called monatomic elements. These are rare. Examples • Elements whose atoms naturally bond into 2 atom units are called diatomic elements. Examples • Distinct groups of atoms bonded together are called molecules. • Chemical Symbol • Each element has its own unique chemical symbol and name • Usually the symbol is based on the name but it might be its Latin or Greek name • Colors- Iridium (Latin for rainbow) • People- Curium (for Pierre and Marie Curie) • Places- Californium • Heavenly bodies- Helium (Helios which is the Greek word for sun) • Miscellaneous- Bromine from the Greek word for stench

7. Compounds and Their Formulas • Compounds • 2 or more elements chemically combined • Some form distinct particles called molecules • Other form vast crystalline arrays that repeat called formula units • Chemical Formulas • Used to represent the millions of kinds of molecules or formula units that make up compounds • Molecule or formula unit has a definite number of atoms • Chemical formulas indicate the number of atoms in each molecule or formula unit • Chemical Subscripts • Small number written at the lower right of a chemical symbol • Tells the number of atoms or moles (groups of atoms) in a chemical formula • Subscript outside of parenthesis- number of molecules of that entire group • Coefficient- in front of the entire chemical formula in a chemical equation. This number applies to the entire chemical formula and it is the number of molecules of the formula

8. Energy and Matter • Energy • Ability to do work • Correlation between energy expended and work done (Physics) • Types of Energy • Potential energy • Kinetic energy • Thermal energy • Energy of atoms as they move around • Sound energy • Energy of periodic waves • Electrical energy • Forces that mover electrically charged particles • Electromagnetic energy • Electric energy that makes magnetic fields • Chemical energy • Energy when atoms bond into new compounds • Nuclear energy • Split the atom or removing particles from the nucleus • Conservation of Energy • Thermodynamics- we will study in greater detail in Chapter 13 • Temperature, Heat, Thermal Energy • Kinetic energy= 1/2mv2 • Internal energy = KE + PE • Temperature = average KE of its particles

9. Temperature • A measure of the average kinetic energy • Different temperature scales, all are talking about the same height of mercury • Derive a equation for converting ºF to ºC

10. 0ºC = 32ºF 32ºF 0ºC

11. 100ºC = 212ºF 0ºC = 32ºF 0ºC 100ºC 212ºF 32ºF

12. 100ºC = 212ºF 0ºC = 32ºF 100ºC = 180ºF 0ºC 100ºC 212ºF 32ºF

13. 100ºC = 212ºF 0ºC = 32ºF 100ºC = 180ºF 1ºC = (180/100)ºF 1ºC = 9/5ºF 0ºC 100ºC 212ºF 32ºF

14. 100ºC = 212ºF 0ºC = 32ºF 100ºC = 180ºF 1ºC = (180/100)ºF 1ºC = 9/5ºF 5/9 °C = 1°F 0ºC 100ºC 212ºF 32ºF For every °C there is 9/5 (or 1.8) °F, but the Fahrenheit scale starts out 32° higher than the Celsius scale, so you must add 32 to any Celsius reading and subtracted from any Fahrenheit reading to correct for the starting point differences. The final formulas for converting from F to C or C to F: (5/9 X °C) + 32 = F or 9/5(°F-32) = C

15. State of Matter • 4 States of Matter • Solid • Liquid • Gas • Plasma • Changes in the Common States of Matter • Condensation • Vaporization • Freeze • Melt • Sublimation • Deposition

16. Measurement and Metrics How we measure in science class

17. TERMS of MEASUREMENT • Dimension • Quantities such as length, mass, volume, etc. • Unit of measure • Either in English or Metric • Scale • Calibrated • Scales are calibrated to make sure they are accurate • Instrument • Artificial device made for the purpose of refining, extending, or substituting for human senses when measuring.

18. Metric Vs. English Units English Units Metric Units Based on division of 10 Have one unit with prefixes for the same measurement Length Weight or mass Volume Speed • Based on Divisions of 8 or 12 • Have multiple units for the same measurement • Length • Weight or mass • Volume • Speed

19. Metric Prefixes in Chemistry

20. SI Base Units

21. Conversion Factors • Unit conversion • Converting from one unit to another with the aid of a… • Conversion factor • Fraction that contains the original unit and its equivalent value in a new unit • 1L = 1000 mL the conversion factor for converting Liters into mL is 1000mL/1L and the conversion factor for converting mL into L is 1L/1000mL • Bridge Notation • Special notation for multiplying and dividing several measurements together at the same time • Can (and will) be used to do any calculations but most often is used when converting units. • Examples of bridge notation