Basic Chem 1411
|Scientific Method|| |
Systematic Approach to Research
|Hypothesis||A tentative explanation for a set of observations.|
|Theory|| A theory is a unifying principle that explains a body of facts and/or those laws that are based on them.|
|Law|| A law is a concise statement of a relationship between phenomena that is always the same under the same conditions.|
Force = mass x acceleration
|Chemistry|| Chemistry is the study of matter and the|
changes it undergoes
|matter||Matter is anything that occupies space and has mass.|
|Substance|| A substance is a form of matter that has a definite composition and distinct properties.|
Eg. Water is composed of H2O and one of its properties is that it freezes at 32F.
|mixture||A mixture is a combination of two or more substances in which the substances retain their distinct identities.|
The result can be mixed in the form of alloys, solutions, suspensions, and colloids
(chemistry) a substance consisting of two or more substances mixed together (not in fixed proportions and not with chemical bonding)
a mixture is a substance containing two or more elements or compounds that are not chemically bound to each other but retain their own chemical and physical identities; - a substance which has two or more constituent chemical substances. Mixtures, in the broader sense, are two or more substances physically in the same place, but these are not chemically combined, and therefore ratios are not necessarily considered.
|Homogenous mixture||mixture that appears the same throughout - uniform in composition. A solution is a homogenous mixture.|
|Solution||In chemistry, a solution is a homogeneous mixture composed of two substances. In such a mixture, a solute is dissolved in another substance, known as a solvent. The solvent does the dissolving.|
A solution is a special type of homogeneous mixture. Solutions are homogeneous because, the ratio of solute to solvent remains the same throughout the solution even if homogenized with multiple sources, and stable because, the solute will not settle out, no matter how long the solution sits, and it cannot be removed by a filter or a centrifuge. This type of mixture is very stable, i.e., its particles do not settle, or separate
|Heterogeneous mixture||composition is not uniform throughout, such as cement or iron fillings in sand.|
|Alloy||Partial or complete solid solution - a mixture containing two or more metallic elements or metallic and nonmetallic elements usually fused together or dissolving into each other when molten.|
Alloying one metal with other metal(s) or non-metal(s) often enhances its properties. For example, steel is stronger than iron, its primary element.
|Suspension|| In chemistry, a suspension is a heterogeneous fluid containing solid particles that are sufficiently large for sedimentation.|
An example of a suspension would be sand in water. The suspended particles are visible under a microscope and will settle over time if left undisturbed.
|Colloid||heterogenous - a mixture containing small, undissolved particles that do not settle out. colloids have the appearance of solutions, colloids are sometimes identified and characterized by their physico-chemical and transport properties. For example, if a colloid consists of a solid phase dispersed in a liquid, the solid particles will not diffuse through a membrane, whereas with a true solution the dissolved ions or molecules will diffuse through a membrane.|
|Element|| An element is a substance that cannot be separated into simpler substances by chemical means|
82 natural elements
32 created by man