Tuesday, October 16, 2007
Tues-Day 1
Bio- Good news, good times: Thanks to Chem teacher extraordinaire, Mrs. Rinaudo, I now have your grades linked on Blackboard. Click on the newly created "Grades" section, enter your Last Name and your cAsE sEnsitIve password and you can view your currently graded tests/assignments.
Today, we explained, step-by-step, the process of diffusion and why diffusion MUST occur as particles RANDOMLY moving in all directions will naturally spread out (diffuse) from a region of higher concentration to a region of lower concentration.
We then carefully went through the diffusion of WATER, which is OSMOSIS (water gets its own special term for diffusion!). The trick is to see that, the MORE things (solutes/salts/molecules) that are dissolved in water, the LESS concentrated the WATER is. The "most" concentrated water is pure, 100%, water. Water will diffuse (undergo osmosis) always from a region of higher water concentration to a region of lower water concentration.
Check out this video of osmosis of water from inside an Elodea plant cell TO a hypertonic
(= very salty!= LOWER water concentration) salt solution.
http://www.linkpublishing.com/Videos/transport/elodea_hyper.wmv
Check out this video of osmosis of water from PURE, distilled water (100% water = higher concentration) outside of an Elodea plant cell TO inside the Elodea plant cell (where there is a LESS THAN 100% water concentration).
http://www.linkpublishing.com/Videos/transport/elodea_hypo.wmv
Here's red BLOOD cells bursting as they are put in distilled, 100% water so that the water diffuses (OSMOSIS) into the red blood cells (about 90% water, 10% solutes).
http://www.linkpublishing.com/Videos/transport/blood_hypo.wmv
Chem 7- we worked Table I into our potential energy/Enthalpy diagrams of chemical reactions and physical changes (dissolving) noting all of the relevant quantities: PE products, PE reactants, delta H = PEp - PEr (pepper!!!), PE activaTED complex,
Eact (activaTION energy)forward reaction, and Eact reverse reaction.
We also did some proportion calculation regarding energy change if more or fewer UNITS (moles) of products are formed than the quantities in the given thermochemical equation.
In the Topic 3 hw packet, you should now be able to answer all of the questions except for the ones on the back of the last page.
Tomorrow, we will discuss/explain the FOUR factors that can affect the rates of chemical reactions and how they do so.
Chem 8/9- we worked Table I into our potential energy/Enthalpy diagrams of chemical reactions and physical changes (dissolving) noting all of the relevant quantities: PE products, PE reactants, delta H = PEp - PEr (pepper!!!), PE activaTED complex,
Eact (activaTION energy)forward reaction, and Eact reverse reaction.
We also did some proportion calculation regarding energy change if more or fewer UNITS (moles) of products are formed than the quantities in the given thermochemical equation.
Tomorrow, we will discuss/explain the FOUR factors that can affect the rates of chemical reactions and how they do so.
In the Topic 3 hw packet, you should now be able to answer all of the questions except for the ones on the back of the last page.
We did a lab in which we measured the delta H of dissolving of NaOH (sodium hydroxide, the base that is used in drain cleaner and soap-making), which is also called the heat of "solution".
We are (again) ignoring any energy absorption by the styrofoam itself; we can do this because styrofoam is a good insulator and does not have a noticeable temperature change during these experiments. So, there is a built-in source of error in our procedure and subsequent calculations( which is the case in ANY experiment though some have more built-in error and some have less).
Today, we explained, step-by-step, the process of diffusion and why diffusion MUST occur as particles RANDOMLY moving in all directions will naturally spread out (diffuse) from a region of higher concentration to a region of lower concentration.
We then carefully went through the diffusion of WATER, which is OSMOSIS (water gets its own special term for diffusion!). The trick is to see that, the MORE things (solutes/salts/molecules) that are dissolved in water, the LESS concentrated the WATER is. The "most" concentrated water is pure, 100%, water. Water will diffuse (undergo osmosis) always from a region of higher water concentration to a region of lower water concentration.
Check out this video of osmosis of water from inside an Elodea plant cell TO a hypertonic
(= very salty!= LOWER water concentration) salt solution.
http://www.linkpublishing.com/Videos/transport/elodea_hyper.wmv
Check out this video of osmosis of water from PURE, distilled water (100% water = higher concentration) outside of an Elodea plant cell TO inside the Elodea plant cell (where there is a LESS THAN 100% water concentration).
http://www.linkpublishing.com/Videos/transport/elodea_hypo.wmv
Here's red BLOOD cells bursting as they are put in distilled, 100% water so that the water diffuses (OSMOSIS) into the red blood cells (about 90% water, 10% solutes).
http://www.linkpublishing.com/Videos/transport/blood_hypo.wmv
Chem 7- we worked Table I into our potential energy/Enthalpy diagrams of chemical reactions and physical changes (dissolving) noting all of the relevant quantities: PE products, PE reactants, delta H = PEp - PEr (pepper!!!), PE activaTED complex,
Eact (activaTION energy)forward reaction, and Eact reverse reaction.
We also did some proportion calculation regarding energy change if more or fewer UNITS (moles) of products are formed than the quantities in the given thermochemical equation.
In the Topic 3 hw packet, you should now be able to answer all of the questions except for the ones on the back of the last page.
Tomorrow, we will discuss/explain the FOUR factors that can affect the rates of chemical reactions and how they do so.
Chem 8/9- we worked Table I into our potential energy/Enthalpy diagrams of chemical reactions and physical changes (dissolving) noting all of the relevant quantities: PE products, PE reactants, delta H = PEp - PEr (pepper!!!), PE activaTED complex,
Eact (activaTION energy)forward reaction, and Eact reverse reaction.
We also did some proportion calculation regarding energy change if more or fewer UNITS (moles) of products are formed than the quantities in the given thermochemical equation.
Tomorrow, we will discuss/explain the FOUR factors that can affect the rates of chemical reactions and how they do so.
In the Topic 3 hw packet, you should now be able to answer all of the questions except for the ones on the back of the last page.
We did a lab in which we measured the delta H of dissolving of NaOH (sodium hydroxide, the base that is used in drain cleaner and soap-making), which is also called the heat of "solution".
We are (again) ignoring any energy absorption by the styrofoam itself; we can do this because styrofoam is a good insulator and does not have a noticeable temperature change during these experiments. So, there is a built-in source of error in our procedure and subsequent calculations( which is the case in ANY experiment though some have more built-in error and some have less).
# posted by C @ 12:12 PM 
