chemlab\

• chemicals are usually stored in reagent bottle
• the reagent bottle covers are usually place on the table in an upside down or inverted position
• wing glass stoppers is placed between the middle finger when transferring the chemicals
• to transfer solid into a test tube, used a paper strip
• to transfer into wide mouth containers, tilt the reagent bottle and carefully rotate it back and forth to allow chemicals to drop to the container.
• precipitation is a method of separating components of mixtures using precipitating agent.
• a solubility is usually used as guide. this method results in the formation of solid particles suspended in the liquid
• the solid particles produced are called precipitate
• in decantation, the supernatant liquid is carefully poured off without disturbing the solid particles after latter has been allowed to settle down.
• solid particles that do not readily settle out are separated from liquid by filtration
• in filtration a filter paper is used that permits the filtrate (liquid portion) to pass through but retains the solid (insoluble salts)
• the filter paper used in the filtration process is folded into half and then in quarter and opened into cone at middle
• for mixture containing soluble salt, the salt is separated through evaporation.
• evaporation is a separation process in which the mixture is heated to an elevated temperature to evaporate the liquid portion leaving behind the soluble salt or residue
• Distillation Distillation is a process or technique of separating liquid components of a mixture from each other.
• Sublimation Sublimation makes use of the special property or characteristic of pure substances of changing in physical state from solid to gas without visible evidence of the liquid state.
• mixtures are the most common form of matter and consist of mixtures of pure substancs
• Matter is anything that takes up space and has mass
• Mass is the amount of matter in an object
• Volume is the amount of space an object takes up
• homogeneous mixtures (uniformly mixed)
• heterogeneous mixtures (not uniformly mixed).
• Mixtures can be separated using physical processes that do not involve the changing of the nature of the pure substances that are in the mixture.
• Physical properties are qualities that described the outside appearance of matter. Examples are odor, taste, color, size and mass or weight.
• Chemical properties can only be determined through the interaction of two or more substances. An example is burning of paper.
• Energy had the ability to do work or to move matter
• CHEMICAL ENERGY o Stored in the bonds of a chemical substances.
• SOLUBILITY – the ability of a substance to be dissolved in another
• BOILING POINT – when a substance changes from a liquid to a gas
• Extensive properties - used to identify a substance, depends on the amount of matter - Examples - mass, weight, volume, length
• Intensive properties - only depends on the type of matter, not only the amount - Examples - color, oder, luster, malleability, ductility, conductivity, hardness, boiling / freezing point, density
• Compounds are substances that can be broken down by chemical methods - When they are broken down, the pieces are completely different properties then the compounds
• Mixtures can be separated using physical process that do not in that do not involve the changing of the nature of the pure Substances that are in the mixtures
• Pure substance can either be compound (combination of more than one type of element)
• The elements in compound can only separated by chemical processes that change the nature of the pure substance
• Elements can combine to form compound through a chemical process that changes their nature