Tuesday, February 26, 2008
Tues-Day 2
Bio- we contrasted the sympathetic and parasympathetic nervous system responses, which are both autonomic (remember "automatic") responses. Sympathetic nervous responses involve electrochemical signals from neurons to glands; the glands are then stimulated to secrete hormones that cause a "fight or flight" response. Parasympathetic nervous responses also involve electrochemical signals from neurons to the same glands; the glands are then stimulated by different/parasympathetic neurotransmitters to secrete hormones that cause a "rest or digest"/ calming response.
We discussed a few disorders/diseases of the nervous system:
- cerebral palsy occurs during fetal development; certain brain cells die for a variety of reasons, which causes the person to have abnormal or insufficient nerve impulses to muscle, which make the person move in an uncoordinated manner. A possible future treatment for this currently untreatable condition that does not change significantly throughout a person's life is to use stem cells to form new neurons and new neuron to muscle reflex arcs.
-meningitis is caused by viruses or bacteria; the immune response to these pathogens inflames/swells the tissues, the meninges, that cover the spinal cord and brain. Treatment with antiviral medicines or antibiotics for bacterial infection may cure the disease. Vaccination may help to prevent infection that causes meningitis.
Chem 7/8- we discussed the components of a hydrate, which is a lattice of ions that contain a set number of water molecules in the lattice per formula unit of the ions. The water molecules are attracted to the ions via ion-dipole attractions, which are not bonds so mild heating can cause the water to vaporize/sublime from the lattice thus forming an "anhydrous" (no water left) salt.
Then, we calculated the percent composition of water in a hydrated salt.
We also determined how to calculate the EMPIRICAL FORMULA (the lowest whole number ratio of atoms or ions of each element in a compound) of a compound FROM the percent composition of elements in the compound. This procedure works due to Dalton's Law of Constant Composition; that is, a given compound has a constant/fixed/set ratio of atoms or ions of each element, therefore a given compound has a constant/fixed/set percent composition by mass based on its ratio of atoms or ions of each element. We saw that sometimes you may have to multiply the mole ratios of the elements in your compounds in order for the compound to have whole number subscripts.
We performed a lab in which we dehydrated a hydrated salt via heating in a crucible. We will use the data to determine the percent composition of water in that hydrate.
Chem 9- We determined how to calculate the EMPIRICAL FORMULA (the lowest whole number ratio of atoms or ions of each element in a compound) of a compound FROM the percent composition of elements in the compound. This procedure works due to Dalton's Law of Constant Composition; that is, a given compound has a constant/fixed/set ratio of atoms or ions of each element, therefore a given compound has a constant/fixed/set percent composition by mass based on its ratio of atoms or ions of each element. We saw that sometimes you may have to multiply the mole ratios of the elements in your compounds in order for the compound to have whole number subscripts.
We discussed a few disorders/diseases of the nervous system:
- cerebral palsy occurs during fetal development; certain brain cells die for a variety of reasons, which causes the person to have abnormal or insufficient nerve impulses to muscle, which make the person move in an uncoordinated manner. A possible future treatment for this currently untreatable condition that does not change significantly throughout a person's life is to use stem cells to form new neurons and new neuron to muscle reflex arcs.
-meningitis is caused by viruses or bacteria; the immune response to these pathogens inflames/swells the tissues, the meninges, that cover the spinal cord and brain. Treatment with antiviral medicines or antibiotics for bacterial infection may cure the disease. Vaccination may help to prevent infection that causes meningitis.
Chem 7/8- we discussed the components of a hydrate, which is a lattice of ions that contain a set number of water molecules in the lattice per formula unit of the ions. The water molecules are attracted to the ions via ion-dipole attractions, which are not bonds so mild heating can cause the water to vaporize/sublime from the lattice thus forming an "anhydrous" (no water left) salt.
Then, we calculated the percent composition of water in a hydrated salt.
We also determined how to calculate the EMPIRICAL FORMULA (the lowest whole number ratio of atoms or ions of each element in a compound) of a compound FROM the percent composition of elements in the compound. This procedure works due to Dalton's Law of Constant Composition; that is, a given compound has a constant/fixed/set ratio of atoms or ions of each element, therefore a given compound has a constant/fixed/set percent composition by mass based on its ratio of atoms or ions of each element. We saw that sometimes you may have to multiply the mole ratios of the elements in your compounds in order for the compound to have whole number subscripts.
We performed a lab in which we dehydrated a hydrated salt via heating in a crucible. We will use the data to determine the percent composition of water in that hydrate.
Chem 9- We determined how to calculate the EMPIRICAL FORMULA (the lowest whole number ratio of atoms or ions of each element in a compound) of a compound FROM the percent composition of elements in the compound. This procedure works due to Dalton's Law of Constant Composition; that is, a given compound has a constant/fixed/set ratio of atoms or ions of each element, therefore a given compound has a constant/fixed/set percent composition by mass based on its ratio of atoms or ions of each element. We saw that sometimes you may have to multiply the mole ratios of the elements in your compounds in order for the compound to have whole number subscripts.
# posted by C @ 1:30 PM 
