Chemistry: The Study of Matter

Chemical symbols There are 109 elements There are 109 elements Each has a 1 or 2 letter symbol Each has a 1 or 2 letter symbol First letter always capitalized second never First letter always capitalized second never Some from Latin or other languages Some from Latin or other languages

Atomic Number Atomic Mass Chemical Symbol

What is Chemistry? The study of matter--its composition, properties, and the changes it undergoes. The study of matter--its composition, properties, and the changes it undergoes. Applied Chemistry is the using chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing Applied Chemistry is the using chemistry to attain certain goals, in fields like medicine, agriculture, and manufacturing Pure chemistry gathers knowledge for knowledge sake Pure chemistry gathers knowledge for knowledge sake

Types of Chemistry Analytical Chemistry studies composition of substances. Analytical Chemistry studies composition of substances. Inorganic Chemistry substances without carbon Inorganic Chemistry substances without carbon Organic Chemistry compounds containing carbon Organic Chemistry compounds containing carbon Biochemistry- Chemistry of living things Biochemistry- Chemistry of living things Physical Chemistry studies behavior of substances Physical Chemistry studies behavior of substances

Today We’ll Learn The molecular composition of matter The molecular composition of matter At the end of the day we want you to know: At the end of the day we want you to know: –What matter is –How it is measured –What the classifies the states of matter

What is Matter? Matter is anything that takes up space and has mass. Matter is anything that takes up space and has mass. Mass is the amount of matter in an object. Mass is the amount of matter in an object. –The amount of stuff in something Volume and Mass= Matter Volume and Mass= Matter Weight is NOT mass Weight is NOT mass D= m/v (g/cm 3 ) D= m/v (g/cm 3 ) So, matter is measured by density So, matter is measured by density

States of matter Solid- matter that can not flow and has definite volume. Solid- matter that can not flow and has definite volume. Liquid- definite volume but takes the shape of its container (flows). Liquid- definite volume but takes the shape of its container (flows). Gas- a substance without definite volume or shape and can flow. Gas- a substance without definite volume or shape and can flow.

States of Matter Solid Liquid Gas Definite Volume? YES NO Definite Shape? YES NO Temp. increase Small Expans. Large Expans. Com- pressible? NO YES

Solid Liquid Gas Melt Evaporate Condense Freeze

Checking for Understanding In your notebooks, either: In your notebooks, either: –Create an analogy that would compare the molecules in a gas, liquid or gas –Draw the molecules in water vapor, soda pop and an ice cube

Matter Terms Atom- Smallest unit of an element that still has the qualities of that element Atom- Smallest unit of an element that still has the qualities of that element Element- Cannot be broken down into simpler particles Element- Cannot be broken down into simpler particles –All one kind of atom Compound- substances that can be broken down by chemical methods Compound- substances that can be broken down by chemical methods –Made from atoms of two or more elements chemically bonded together –When they are broken down, the pieces have completely different properties than the compound. Molecule- smallest unit of a compound that maintains the properties of the compound Molecule- smallest unit of a compound that maintains the properties of the compound –Can be one type of atom or many types

Which is it? Made of 1 type of atom Made of 1 type of atom –Element 1 unit of hydrogen and oxygen 1 unit of hydrogen and oxygen –Molecule Calcium Calcium –Element 2 Hydrogens bonded together 2 Hydrogens bonded together –Molecule Smallest unit of a compound Smallest unit of a compound –Molecule 1 particle of neon 1 particle of neon –Atom

Which is it? Atom Element Compound Molecule

Properties of Matter Words that describe matter Words that describe matter Physical Properties- a property that can be observed and measured without changing the substance. Physical Properties- a property that can be observed and measured without changing the substance. –Density, reactivity, boiling point Chemical Properties- a property that can only be observed by changing the type of substance. Chemical Properties- a property that can only be observed by changing the type of substance.

Changes A change in appearance, without changing the composition. A change in appearance, without changing the composition. Boiled water is still water. Boiled water is still water. Chemical changes - a change where a new form of matter is formed. Chemical changes - a change where a new form of matter is formed.

Indications of a chemical reaction Energy absorbed or released Energy absorbed or released –Endothermic: More energy is needed to start the reaction than is given off –Exothermic: Gives off energy than it takes in Color change Color change Gas is released Gas is released Precipitate- solid that separates from solution Precipitate- solid that separates from solution

Chemical Reactions When one or more substances are changed into new substances. When one or more substances are changed into new substances. Reactants- stuff you start with Reactants- stuff you start with Products- What you make Products- What you make NEW PROPERTIES NEW PROPERTIES Not easily reversed Not easily reversed A + B AB

In Your Notebook Give an example of a physical AND chemical change that wasn’t given in class Give an example of a physical AND chemical change that wasn’t given in class

Conservation of Mass Mass- A measure of the amount of “stuff” in an object Mass- A measure of the amount of “stuff” in an object –Is a measure of matter Measured on a balance Measured on a balance Mass can not be created or destroyed in ordinary (not nuclear) changes. Mass can not be created or destroyed in ordinary (not nuclear) changes. All the mass can be accounted for. All the mass can be accounted for. E=mc 2 E=mc 2 –Energy, Mass

Energy Kinetic- Energy of Motion Kinetic- Energy of Motion –Measure of heat (in chemistry) Potential- Energy of Height Potential- Energy of Height Chemical Energy- energy that comes from the breaking of chemical bonds Chemical Energy- energy that comes from the breaking of chemical bonds –Example: H 2 0

Endothermic Energy is absorbed during this kind of reaction Energy is absorbed during this kind of reaction The products of the reaction take in energy The products of the reaction take in energy –The reaction ends up with more energy than it started with Example: melting an ice cube, evaporating water, baking bread Example: melting an ice cube, evaporating water, baking bread

Endothermic Reactants

Exothermic Energy is released during this kind of reaction Energy is released during this kind of reaction The products of the reaction give off energy The products of the reaction give off energy –The reaction starts out with more energy than it ends with Example: hot packs, glue ball Example: hot packs, glue ball