What is Chemistry? Using all of the letters in the word chemistry, describe your expectations from this course.
Chapter One:Matter & Change Created by: Stephen Cotton Edited by: Corey Nichols
Chemistry Is a Physical Science Chemistry is the study of the composition, structure, and the properties of matter and the changes it undergoes. There are 6 main branches of chemistry: Organic, Inorganic, Physical, Analytical, Biochemistry, and Theoretical
Research Scientists are constantly searching for answers to common and complex questions. They find their answers using research. Basic research: research done for the sake of increasing knowledge about a particular subject Applied research: research done to solve a problem
Research (cont’d) Eventually, research will give rise to advancements in our everyday lives. Technological development: production and use of products that improve our quality of life.
What is matter? Matter is anything that: has mass, and takes up space Mass = a measure of the amount of “stuff” (or material) the object contains (don’t confuse this with weight, a measure of gravity) Volume = a measure of the space occupied by the object
Describing Matter Properties used to describe matter can be classified as: Extensive – depends on the amount of matter in the sample - Mass, volume, calories are examples Intensive – depends on the type of matter, not the amount present - Hardness, Density, Boiling Point
Properties are… Words that describe matter (adjectives) Physical Properties- a property that can be observed and measured without changing the material’s composition. Chemical Properties- a property that can only be observed by changing the composition of the material.
States of matter Solid- matter that can not flow (definite shape) and has definite volume. Liquid- definite volume but takes the shape of its container (flows). Gas- a substance without definite volume or shape and can flow.
States of Matter Definite Volume? Definite Shape? Will it Compress? Solid YES YES NO Liquid YES NO NO Gas YES NO NO
Condense Freeze Evaporate Melt Gas Liquid Solid
Physical vs. Chemical Change Physical change will change the visible appearance, without changing the composition of the material. Can be reversible, or irreversible Chemical change - a change where a new form of matter is formed.
Mixtures Mixtures are a physical blendof at least two substances; have variable composition. They can be either: Heterogeneous – the mixture is not uniform in composition Chocolate chip cookie, gravel, soil. Homogeneous - same composition throughout; called “solutions” Kool-aid, air, salt water Every part keeps it’s own properties.
Solutions are homogeneous mixtures Mixed molecule by molecule, thus too small to see the different parts Can occur between any state of matter: gas in gas; liquid in gas; gas in liquid; solid in liquid; solid in solid (alloys), etc. Thus, based on the distribution of their components, mixtures are called homogeneous or heterogeneous.
Phase? The term “phase” is used to describe any part of a sample with uniform composition of properties. A homogeneous mixture consists of a single phase A heterogeneous mixture consists of two or more phases.
Separating Mixtures Some can be separated easily by physical means: rocks and marbles, iron filings and sulfur (use magnet) Differences in physical properties can be used to separate mixtures. Filtration - separates a solid from the liquid in a heterogeneous mixture
Pure Substances Pure substances are substances that have a fixed composition. Pure substances are divided into 2 main types: Elements Compounds
Pure Substances Elements- simplest kind of matter cannot be broken down any simpler and still have properties of that element! all one kind of atom. Compounds are substances that can be broken down only by chemical methods when broken down, the pieces have completely different properties than the original compound. made of two or more atoms, chemically combined (not just a physical blend!)
Compound vs. Mixture Made of one kind of material Made of more than one kind of material Made by a chemical change Made by a physical change Definite composition Variable composition Compound Mixture
Which is it? Element Compound Mixture
Elements vs. Compounds Compounds can be broken down into simpler substances by chemical means, but elements cannot. A “chemical change” is a change that produces matter with a different composition than the original matter.
Chemical Change A change in which one or more substances are converted into different substances. Heat and light are often evidence of a chemical change.
Properties of Compounds Quite different properties than their component elements. Due to a CHEMICAL CHANGE, the resulting compound has new and different properties: Table sugar – carbon, hydrogen, oxygen Sodium chloride – sodium, chlorine Water – hydrogen, oxygen
Flashback In the following commercial, determine what type of matter is being advertised. Be sure to explain how you derived your answer.
The Periodic Table Currently, there are 117 elements Elements have either a 1 or two letter symbol. An element’s first letter always capitalized; if there is a second letter, it is written lowercase: B, Ba, C, Ca, H, He Some names come from Latin or other languages
Ins and Outs of the Periodic Table Groups: vertical columns of elements on the periodic table; also called families There are 18 groups on the periodic table. Elements within a group share similar properties. Periods: horizontal rows of elements on the periodic table; also called series. In total, there are 7 periods on the periodic table.
Types of Elements There are various types of elements on the periodic table. We will discuss 4 main types of elements: Metals Nonmetals Metalloids Noble gases
Metals Metals: elements that are good conductors of heat and electricity Found to the left of the zig-zag line Properties of Metals include: Luster (shininess) Solids at room temperature Malleable (able to be hammered or rolled into thin sheets) High tensile strength; ductile
Nonmetals Nonmetals: elements that are poor conductors of heat and electricity Found to the right of the zig-zag line Properties include: Brittle Can be solid, liquid or gas at room temperature
Metalloids Metalloids: elements that have some properties of metals and some properties of nonmetals Found on either side of the zig-zag line Properties include: Semiconductors Solid at room temperature
Noble Gases Noble gases: elements that are located in Group 18 Found on the far right side of the periodic table Properties include: Unreactive (or inert) Gases at room temperature