Do-now  Hand in Lab Reports!  Grab a syringe from the front

BONUS CHEMISTRY!!!!! Gas Laws

Kinetic Theory of Gases  Gases, being compressible, exert a Pressure on the surrounding environment  Measured in atm (bar), Pa, kPa, or mm Hg

Boyle’s Law  Let’s see if you can completely compress the gas in the syringe  As you push down, the gas pushes back more and more  Boyle’s Law states that the volume of a gas varies inversely with pressure P 1 x V 1 = P 2 x V 2

Charles’s Law  What happens when you heat a gas? When you cool a gas?  Charles’s Law states that the volume of a fixed mass of a gas is directly proportional to its volume  Temperature must be in Kelvin

Gay-Lussac’s Law  As the temperature of a gas increases, what happens to the pressure the gas exerts?  Gay-Lussac’s Law states that the pressure a gas exerts is directly proportional to the temperature of the gas

Combined Gas Law  The combined gas law merges all three of the gas laws  Again, Temperature must be in K

Animation

1. A gas occupies 1.56 L at 1.00 atm. What will be the volume of this gas if the pressure becomes 3.00 atm? 2. Given mL of a gas at 17.0 °C. What is its volume at 10.0 °C? 3. If a gas is cooled from K to K and the volume is kept constant what final pressure would result if the original pressure was mmHg? 4. What is the final volume of a mL gas sample that is subjected to a temperature change from 22.0 °C to 30.0 °C and a pressure change from mmHg to mmHg?

Ideal Gas Law  Up until now, we’ve assumed that the amount of gas does not change  But what if it does? How do you think amount of gas affects P, V, and T?  n= number of moles  R=ideal gas constant (8.31 (L x kPa)/(K x mol) PV=nRT

Practice- Ideal Gas Law  A helium-filled balloon contains 0.16 mol of He at 101 kPa at 23 º C. What is the volume of gas of the balloon?  (3.9 L)

Do-now  How many moles of gas does it take to occupy 120 liters at a pressure of 2.3 atmospheres and a temperature of 340 K?

Do-now  Work on p. 480, questions in GROUPS!  Turn in for a classwork grade (1 per person)  When you are done, grab goggles and aprons. Pick up a copy of the activity from the side and begin working with your partner.

Acids and Bases

Acids/Bases in water  An acid will dissolve to produce hydronium ion (H 3 O + )  HCl + H 2 O  H 3 O + + Cl -  A base will dissolve in water to produce hydroxide ion (OH - )  NaOH  Na + + OH -

Concentration  In chemistry, concentration is typically measured in molarity.  1 M= 1 mol/L Molarity=moles of solute /Liters of solution

Self-ionization of water

The pH concept  How do we find the concentration of Hydrogen ions in solution? We use something called pH  The lower the pH, the higher concentration of H + ions  A solution with a pH less than 7 is acidic. A solution with a pH greater than 7 is basic pH = -log[H + ]

Problems  What is the pH of a solution with [H + ] = 1.0 x ?  What is the hydrogen ion concentration of apple juice? (pH=2.7)

pOH  pOH could be considered the opposite of pH  pH + pOH is always equal to 14, therefore: pOH=-log[OH - } pOH= 14- pH

Find the pH  [OH - ]=1.0 x M  [H + ]= 7.7 x M

HW  STUDY!

Do-now:  P. 684, questions (Hand in!)

Nuclear Chemistry!

Bill Nye  A_LfcFVI A_LfcFVI

Radiation  Certain isotopes of elements, called “Radioisotopes”, are unstable.  They lead to nuclear radiation, which are rays and particles emitted from the nucleus

Types of radiation- α  Alpha particles are physically equivalent to a helium nucleus  When an α particle is emitted, the atomic number is lowered by 2 and the mass number is lowered by 4 If Uranium-238 emits an alpha particle, what does it become?

Types of radiation- β  Beta particles are electrons breaking apart of a neutron in an atom  The result is a neutron becoming a proton! (Atomic number increases by 1  What does Carbon-14 become when it emits a beta particle?

Types of radiation- γ  Gamma radiation is a high energy photon emitted from a nucleus  Does not affect the mass or charge of the nucleus, but usually emitted alongside alpha or beta particles

Question  The following undergo alpha decay. What are their products?  Uranium-238,  Uranium-235,  Thorium-230,  Radon-222  The following undergo beta decay. What are their products?  Carbon-14  Strontium-90  Potassium-40  Nitrogen-13

Why do these things decay?

Nuclear force  The nuclear force is a strong force that acts at very small distances to keep neutrons together  Constantly at odds with electromagnetic force

The band of stability  Nuclei within the band of stability will not emit radiation  This is all relative to their neutron/proton ratio (n/z)

Chain Reactions- Fission  When nuclei of certain isotopes are bombarded with neutrons, fission, or splitting of the atom, may occur.  Leads to a chain reaction

Fusion  When nuclei combine to form a new nucleus of greater mass, it is called fusion

Complete the reaction

Now study!