Saturday, February 16, 2008
Fri-Day 2
Bio- we continued our discussion of the nervous system. We can separate the nervous system into two main sections: the central nervous system and the peripheral nervous system. We first are focusing on the central nervous system organs: the brain and the spinal cord. We discussed the structures and functions of the main parts of the brain: the cerebrum (thinking, memory, processing information from the five senses), the cerebellum (balance and coordination), and the medulla oblongata (involuntary control of breathing rate).
We saw a brief video of the central nervous system that showed a REFLEX ARC, which is a series of nerve impulses starting with a stimulus to the RECEPTORS on the sensory neurons, which relay impulses to the interneurons, which then relay impulses to motor neurons, which then cause contractions in muscles or secretions in glands. Glands and muscles are the EFFECTORS of the reflex arc.
On Blackboard this week, check your answers to the worksheets given out in class on Friday.
Chem 7/8- we finished the various "mole triangle" calculations involving inter-conversions from grams to moles to particles to moles to liters (at STP). We showed the importance of writing out the units AND the substances in ALL calculations so that you can keep track of what you are actually doing.
We then did some "percent composition" calculations. Percent composition means the percent composition BY MASS of a particular element in a compound. That is, if you take a mole of a compound, say H2O, and decompose it into its elements, H and O, you would always get the same ratio or percent of the masses of its elements; to see this, take ONE MOLE of the compound, e.g. one mole of H2O and get its mass; the formula (molecular) mass of H2O is 18.0 grams (per mole) and 2.0 of those 18.0 grams comes from the H and 16.0 of those 18.0 grams comes from O. Therefore, 2.0/18.0 is the (mass) fraction of H in water and that fraction can be converted to a percent by multiplying the fraction by 100 and putting a % symbol after the number calculated; so, water is 11.1% H and 16.0/18.o O, which is 88.9% O.
Chem 9- we finished the various "mole triangle" calculations involving inter-conversions from grams to moles to particles to moles to liters (at STP). We showed the importance of writing out the units AND the substances in ALL calculations so that you can keep track of what you are actually doing.
We then did some "percent composition" calculations. Percent composition means the percent composition BY MASS of a particular element in a compound. That is, if you take a mole of a compound, say H2O, and decompose it into its elements, H and O, you would always get the same ratio or percent of the masses of its elements; to see this, take ONE MOLE of the compound, e.g. one mole of H2O and get its mass; the formula (molecular) mass of H2O is 18.0 grams (per mole) and 2.0 of those 18.0 grams comes from the H and 16.0 of those 18.0 grams comes from O. Therefore, 2.0/18.0 is the (mass) fraction of H in water and that fraction can be converted to a percent by multiplying the fraction by 100 and putting a % symbol after the number calculated; so, water is 11.1% H and 16.0/18.o O, which is 88.9% O.
We saw a brief video of the central nervous system that showed a REFLEX ARC, which is a series of nerve impulses starting with a stimulus to the RECEPTORS on the sensory neurons, which relay impulses to the interneurons, which then relay impulses to motor neurons, which then cause contractions in muscles or secretions in glands. Glands and muscles are the EFFECTORS of the reflex arc.
On Blackboard this week, check your answers to the worksheets given out in class on Friday.
Chem 7/8- we finished the various "mole triangle" calculations involving inter-conversions from grams to moles to particles to moles to liters (at STP). We showed the importance of writing out the units AND the substances in ALL calculations so that you can keep track of what you are actually doing.
We then did some "percent composition" calculations. Percent composition means the percent composition BY MASS of a particular element in a compound. That is, if you take a mole of a compound, say H2O, and decompose it into its elements, H and O, you would always get the same ratio or percent of the masses of its elements; to see this, take ONE MOLE of the compound, e.g. one mole of H2O and get its mass; the formula (molecular) mass of H2O is 18.0 grams (per mole) and 2.0 of those 18.0 grams comes from the H and 16.0 of those 18.0 grams comes from O. Therefore, 2.0/18.0 is the (mass) fraction of H in water and that fraction can be converted to a percent by multiplying the fraction by 100 and putting a % symbol after the number calculated; so, water is 11.1% H and 16.0/18.o O, which is 88.9% O.
Chem 9- we finished the various "mole triangle" calculations involving inter-conversions from grams to moles to particles to moles to liters (at STP). We showed the importance of writing out the units AND the substances in ALL calculations so that you can keep track of what you are actually doing.
We then did some "percent composition" calculations. Percent composition means the percent composition BY MASS of a particular element in a compound. That is, if you take a mole of a compound, say H2O, and decompose it into its elements, H and O, you would always get the same ratio or percent of the masses of its elements; to see this, take ONE MOLE of the compound, e.g. one mole of H2O and get its mass; the formula (molecular) mass of H2O is 18.0 grams (per mole) and 2.0 of those 18.0 grams comes from the H and 16.0 of those 18.0 grams comes from O. Therefore, 2.0/18.0 is the (mass) fraction of H in water and that fraction can be converted to a percent by multiplying the fraction by 100 and putting a % symbol after the number calculated; so, water is 11.1% H and 16.0/18.o O, which is 88.9% O.
# posted by C @ 10:24 PM 
