Word of the Day for August 27, 2008 Chemical Property Definition - any property of a substance that must be observed during a chemical change. One chemical property of magnesium is that it will combine with oxygen to produce heat and light.
Chemistry Objective: SWBAT -> 1. define matter. 2. describe matter as pure and impure. Chemistry Warm-Up: What is your definition of Chemistry?
Chemistry (from the Dictionary) -> the science that deals with the composition and properties of substances and various elementary forms of matter. the definition that we will use is Chemistry is the study of Matter and its Interactions.
But what is MATTER? Remembering back to the middle school definition: MATTER is anything that has mass and takes up Space.
Matter has Mass & Volume. Pure Impure
Pure Matter made up of ONLY one type of substance. Elements A substance that cannot be reduced to simpler substances by normal chemical means and that is composed of atoms having an identical number of protons in each nucleus. ex. Gold, Oxygen, Mercury (Au) (O) (Hg) can be of TWO Types. Compounds A pure substance consisting of atoms or ions of two or more different elements in definite proportions that cannot be separated by physical means. A compound usually has properties unlike those of its constituent elements. ex. Water, Salt, Carbon Dioxide (H2O) (NaCl) (CO2)
Compounds can be of two types. Organic noting or pertaining to a class of chemical compounds that contain carbon and hydrogen, with the exception of carbonates, oxides, and minerals. Inorganic all other types of chemical compounds including carbonates, and carbon oxides.
Matter Pure Impure Elements Compounds Organic Inorganic
Homogeneous mixtures that have a definite composition and properties, for example, any amount of a given mixture has the same composition and properties. are also known as SOLUTIONS ex. saline solution hospital IV brass (an alloy of copper & zinc) Impure Matter aka. Mixtures substance containing two or more elements or compounds that still retain their separate physical and chemical properties. can be of TWO Types. Heterogeneous mixtures without definite composition, containing several phases. An example is the parts of a heterogeneous composition, which can be mechanically separated from the rest.
Heterogeneous can be separated into two categories based on the size of the particles. Colloids a mixture in which one substance is divided into minute particles and dispersed throughout a second substance. These particles are small enough to stay suspended within the mixture. ex. Fog - H2O in air Smoke - C in air Milk The Tyndall effect can be used to differentiate a true solution from a colloidal Suspensions a mixture of two substances, one of which is finely divided and dispersed in the other which appears uniform until agitation ceases. If allowed the particles will settle out of the liquid phase. ex. oil-based paint sand in water salad dressing
Matter Pure Impure
Matter Pure Impure Elements Organic Compounds Inorganic Homogeneous Heterogeneous Colloid Suspension
Chemistry Objective: SWBAT -> 1. differentiate between Chemical and Physical Properties. 2. differentiate between Chemical and Physical Changes. Chemistry Warm-Up: List three properties of water you know.
Matter in general Various states of matter: Some Characteristics of Gases, Liquids and Solids and the Microscopic Explanation for the Behavior Gases Liquids Solids assumes the shape and volume of its container particles can move past one another compressible lots of free space between particles flows easily assumes the shape of the part of the container which it occupies particles can move/slide past one another not easily compressible little free space between particles flows easily retains a fixed volume and shape rigid - particles locked into place not easily compressible little free space between particles does not flow easily
Matter in general Various states of matter: Plasma is overwhemingly the dominant constituent of the universe as a whole. Yet most people are ignorant of plasmas. In daily life on the surface of planet Earth, perhaps the plasma to which people are most commonly exposed is the one that produces the cool efficient glow from fluorescent lights. Neither solid, nor liquid, nor gas, a plasma most closely resembles the latter, but unlike gases whose components are electrically neutral, plasma is composed of the building blocks of all matter: electrically charged particles at high energy.
Matter & Energy Changes At points where the graph is increasing, each sample of matter is simply warming up. At points in the graph where the line appears to be no change in energy, or horizontal, the form of matter is changing from the state with less internal energy to one with more internal energy, for example - from a solid to a gas.
Word of the Day for August 28, 2008 Intensive / Extensive Properties Definition - Extensive Property - any property that is dependent upon the amount of matter present. Intensive Property - any property that is independent of the amount of matter present.
Matter & its Properties is said to have two types of properties. Extensive a property that is dependent upon the amount of matter present. ex. mass volume length area state Intensive a property that is independent of the amount of matter present. ex. density melting point color texture odor Physical Chemical
Physical Properties any property of matter that can be observed without changing the identity of the substance or without undergoing a chemical change. Extensive Physical Properties ex. mass weight length volume state Intensive Physical Properties ex. color luster malleability ductility conductivity hardness melting/freezing point boiling point density
Chemical Properties becomes apparent during a chemical reaction, and can only be observed by changing a substance's chemical identity. Intensive Chemical Properties ex. ionization energy electronegativity flammability odor / aroma taste reactivity with acid
Physical a change which does not produce a new form of matter. Usually Physical Changes are considered to be changes in the state of matter and are reversible. ex. - melting / freezing - condensation / evaporation - sublimation Matter & its Changes is said to undergo two types of changes. Chemical a change which produces a new form of matter and are not reversible. Chemical changes are always accompanied by a change in energy. ex. - combustion - oxidation
REVIEW: 1. Identify each as a chemical or physical property. a. volume b. flammability c. solid @ room temp. 2. Classify each of the following changes as either chemical or physical. a. coffee being ground b. sugar dissolving in tea c. cooking a pancake 3. How do compounds differ from homogeneous mixtures?