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REVISION. Lab ( 6 ) Solutions. Solutions Solution: is the homologous mixture of 2 or more substances in different proportion,substances can be solids, liquids or gases or combination of the three. .
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Lab ( 6 ) • Solutions
Solutions Solution:is the homologous mixture of 2 or more substances in different proportion,substances can be solids, liquids or gases or combination of the three.
Living organism’s tissue contains high percentage of aqueous solutions called Tissue fluidand divided into: • 1) Intercellular fluid 2)extracellular fluid • -These fluids serves in exchanging substances between cell and its surrounding to insure performing vital biological functions of the cell and to maintain cell shape and volume. • -Water is the main component of living cell and protoplasm, and the main solvent on living tissues.
Physical and Chemical Properties of Water 1- Water has broad range between freezing and boiling degrees. 2- Has the ability to bind to macromolecules such as proteins, carbohydrates and nucleic acids with hydrogen bonds (H-bond). 3- Has many physical characteristics such as: surface tension, viscosity, cohesion and adhesion. 4- Polarity of water helps adhesion to surface of many molecular organic components such as: starch, proteins and moisten them and form colloidal solutions. 5- Water is an ideal solvent of wide range of ionic substances, also to non-ionic substances. 6- water is inactive chemically. This property provides ideal medium for biochemical reactions such as photosynthesis.
Types of Aqueous Solutions 1- True Solution: homologous, does not precipitate with time, and filtrate through filter paper such as aqueous sucrose solution and copper sulphate solution. 2- Suspension: Heterogeneous. Solute particles diffuse into large particles that can be seen by eye or microscope. They do not filtrate through filter paper, and can be easily separated such as aqueous solution of calcium sulphate.
3- Emulsion: The mixture of 2 immiscible liquids (such as water and oil). One liquid particles suspend in form of tiny globes in the other liquid, and when left aside they separate into two layers. By adding a emulsifying agent (as NaOH) it helps stabilize the emulsion. 4- Colloidal solution: Molecules spread between solvent’s particles, and does not precipitate or float. Also they do not filtrate through membranes (animal membranes or artificial membranes such as cellophane), but they can filtrate though regular filter paper. Colloidal solutions are viscous. Solute is called dispersed phase, and the solvent is called dispersion medium. (surface aggregation- Brownian motion- membrane semi-permeability- The ability to absorb water )
Lab ( 9 ) Diffusion, Osmosis and Photosynthesis
Diffusion:The net spontaneous movement (transport)of particles through a semi-permeable membrane resulting from particles motion energy, and driven by concentration gradient in the medium.
Examples for Diffusion O2 and CO2 diffusion in leaf (photosynthesis) • Plant root absorption of water Exchange of O2 and CO2 in animal lung
Diffusion Through Cellular Membranes: The membrane is a barrier separates two mediums. 1-natural : ex.the cellular (plasma) membrane 2-artificial : ex. cellophane plasma cellophane
Osmosis:is the diffusion of water from a diluted solution to concentrated solution through a semi-permeable membrane. Osmotic Pressure: is the force that pulls water molecules from the surrounding. concentration of solutes osmotic pressure
Experiments on Osmosis
Photosynthesis:Green plants and some protozoa (cyanobacteria and algae) can build their own nutrients via photosynthesis, They absorb light energy and coverts it into chemical energy, producing organic compounds. Carbon dioxide + water + sunlight = sugar + oxygen
Assignment (9): Fill in the table with your results: 1) Diffusion Experiment:
- Put ( T ) for true statements and ( F ) for false statements:
-Fill in the blanks with the correct word to complete the following phrases
- From the data given, how to prepare the following issues . SHOW ME YOUR CALCULATIONS AND PLEASE DO NOT FORGET UNITS!!).
ملاحظة: سيتم وضع الخطوات (Steps) مكتوبة أمام كل تجربة في اختبار المعمل.