Chapter 1-2 Flashcards
Define chemical change/chemical reaction.
A change in which one or more new substances with different properties are formed as evidenced by changes in colour, energy, odour, or state; the study of chemicals and their reactions, associated technologies, and environmental effects.
Define observation.
A direct form of knowledge obtained by means of one of the five human senses and can be classified as qualitative or quantitative observation.
Define qualitative observation.
An observation that describes qualities of matter or changes in matter. (e.g. odour, colour, and physical state); observation with no numerical value.
Define quantitative observation.
An observation that involves one or more measurements of some property; observations with numerical value.
Define interpretation.
An indirect form of knowledge that builds upon a concept or an experience to further describe or explain an observation (included in the analysis).
Define empirical knowledge.
Knowledge gained through observation (observable knowledge). Observations are always empirical.
Define theoretical knowledge.
Knowledge that explains and describes scientific observations in terms of non-observables.
Define empirical descriptions.
Communicates a single item of empirical knowledge, that is, an observation.
Define empirical hypotheses.
Preliminary generalizations that require further testing.
Define empirical definitions.
Statements that define an object or a process in terms of observable properties.
Define generalizations.
Statements that summarize a limited number of empirical results. They are usually broader in scope than empirical definitions and often deal with a minor or sub-concept.
Define scientific laws.
Statements of major concepts based on a large body of empirical knowledge. Laws are more important and summarize more empirical knowledge than generalizations.
Define matter.
Anything that has mass and occupies space; may be a pure substance or a mixture.
Define pure substances.
Matter whose composition is constant and uniform; composed of only one kind of chemical and cannot be separated by physical methods.
Define mixtures.
Matter whose composition includes two or more substances and may or may not be uniform throughout the sample. (i.e. homogenous or heterogenous)
Define heterogeneous mixture.
A mixture that is non-uniform, and may consist of more than one phase. Heterogeneous mixtures can be separated by physical means (i.e. filtration, distillation, chromatography, mechanically extracting one component from the mixture, allowing one component to separate and settle, or use a magnet to separate certain metals.)
Define chemical decomposition.
Separating a compound into its elements.
Define elements.
A pure substance that cannot be broken down into simpler chemical substances by physical or chemical means; consists of only one atom.
Define entity.
A general term that includes atoms, ions, and molecules.
Define atom.
The smallest entity of an element that is still characteristics of that element.
Define compounds.
A pure substance that can be separated into its elements by heat or electricity; a substance containing atoms/ions of more than one element in a definite fixed proportion. Compounds can only be separated by means of a chemical change involving heat or electricity.
Define chemical formula.
A series of symbols representing the atoms/ions and their proportions present in a pure substance.
What is the periodic table of elements and who created it?
The periodic table of elements communicates the periodic law (chemical and physical properties of elements that repeat themselves in regular intervals, when they are arranged in order of increasing atomic number.) The table organizes the elements in groups and periods as metals and non-metals.
It was created by Dmitri Mendeleev, a Russian chemist, in 1869.
What is a family/group in the periodic table of elements?
Family/groups have similar chemical properties and includes the elements in a vertical column in the main part of the table.
What is a period in the periodic table of elements?
A period is the horizontal row of elements whose properties gradually change from metallic to non-metallic from left to right along the row.
Location of metals, non-metals, and semi-metals in the periodic table of elements.
Metals on the left of the staircase line. Non-metals are on the right. Semi-metals (metalloids) are a class of elements distributed along the staircase line.