B) permanent dipoles of molecules containing covalent bonds between atoms of very different electronegativities. C) the hydrophobic effect. D) ion pairing between oppositely charged functional groups. Answer: A Page Ref: Section 5 28) The aggregation of nonpolar molecules or groups in water is thermodynamically due to the A) increased entropy of the nonpolar molecules when they associate. B) decreased enthalpy of the system.
Two pop cans are mounted on Styrofoam cups using scotch tape. The cans are placed side-by-side and a negatively charged rubber balloon (having been rubbed with animal fur) is brought near to one of
Osmosis is the diffusion of water across a semi permeable membrane. The semi permeable membrane acts like a filter that lets only the water through. Water always goes from the area of higher water concentration to the area of lower water concentration. Confused? Then imagine the particles (or solute) are salt and follow the rule - SALT SUCKS!
Sucrase activity steadily increases with increasing sucrose concentration until a plateau is reached. 6. Was the rate of increase of sucrase activity greater when sucrose concentration went from 2.5 to 7.5 g/l or when it went from 22.5 to 27.5 g/l? pH Along the GI Tract Organ pH Mouth 6.35 – 6.85 Stomach 1 - 3 Duodenum (first section of small intestine) 6 Jejuneum (second section of small intestine) 7.5 Ileum (third section of small intestine) 7.5 Colon 7.5 -
| Investigating Osmosis Through Living Membranes | Introduction: Diffusion is the tendency of molecules or ions to move from an area where they are in higher concentration to an area where they are in lower concentration, that is, down or along their concentration gradient (Marieb 2013). Osmosis is a special case of diffusion defined as the diffusion of a solvent, such as water, through a selectively permeable membrane (Marieb 2013). Osmosis occurs whenever the water concentration differs on the two sides of a membrane. Take a U-shaped container filled with a solution and separate the container into left and right compartments by a permeable membrane. Normally, net diffusion of both solute and water occurs until the concentration of water (and solute) is the same on both sides of the membrane (equilibrium).
Introduction Nucelophilic substitutions are chemical reactions in which an electron rich nucleophile attacks the electron poor electrophile1. There are two classes of nucelophilic reactions – SN1, and SN2. The SN1 reaction is a 2 step, uni-molecular reaction, which is independent of the nucleophile. It requires a highly substituted electrophile since there is a formation of a carbocation in its rate determining step, good polar protic solvents which stabilize the carbocation and a good leaving group1. On the other hand, a SN2 reaction is a concerted, bimolecular reaction which has one slow, transition state1.
11.2 Particulate Model for Solids, Liquids and Gases A block of ice Solid molecules have a restricted motion = Solid A beaker of boiling water Gas molecules are able to move at extremely high speed = Gas A beaker of warm water liquid molecules have greater mobility = Liquid States of Matter Solid * In solids, the molecules are arranged close together in a regular pattern * Strong attractive intermolecular forces hold the molecules in position so they have definite shape and volume * They can only vibrate in their fixed positions Liquid * In liquids, the molecules are not arranged in a regular pattern and are slightly further apart then those in solids * The attractive intermolecular forces are not very strong. Thus, the molecules are able to move among one another, giving liquids its definite volume but not a definite shape. Gases * In gases, the molecules are widely spaced. Intermolecular forces are negligible * The molecules move about randomly with high speeds, colliding with the walls of the container, occupying any available space. Research on *phase changes for water* Heating curve (Please!!!!!!
As the vibrating string moves in the forward direction, it begins to push upon surrounding air molecules, moving them to the right towards their nearest neighbor. This causes the air molecules to the right of the string to be compressed into a small region of space. As the vibrating string moves in the reverse direction (leftward), it lowers the pressure of the air immediately to its right, thus causing air molecules to move back leftward. The lower pressure to the right of the string causes air molecules in that region immediately to the right of the string to expand into a large region of space. The back and forth vibration of the string causes individual air molecules (or a layer of air molecules) in the region immediately to the right of the string to continually vibrate back and forth horizontally.
In order to do so, the balloon has to be filled with air that is not as dense than the air around it. The buoyant force would lift the balloon, but the air pressure would have to be kept the same. Air pressure is another significant principle that goes into making a hot air balloon fly. Air pressure is caused by gas particles colliding frequently into each other as well as into the walls of what is containing it, in this case, a balloon. The amount of air pressure depends on how often these particles collide.
Aluminum, for example, expands twice as much as iron when both are heated the same amount. Rubber and water are two common substances that differ from most others in their response to heat. Rubber contracts when heated. Water loses volume when its temperature rises from 0° C. to 4° C. (32° F. to 39° F.). It expands when its temperature rises above 4° C. (39° F.).