Chapter 1 Matter, Measurement, and Problem Solving Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro 2008, Prentice Hall Ms. Knick HAHS Honors Chemistry 1A

Tro's "Introductory Chemistry", Chapter 1 2 What Is Chemistry? Observation: is sand different than water Test the similarities and differences between sand and water. Composition  Types & number of atoms, structure, Properties  Chemical: how hot, how fast  Physical: size, ability to loose/gain electrons Chemistry is the study of the composition and properties of matter.

Matter Matter is anything that has mass and takes up space (volume) Tro, Chemistry: A Molecular Approach3

6 Branches of Chemistry 1. Organic Chemistry- The study of most carbon containing compounds. Example: C 6 H 12 O 6 (Sugar)

6 Branches of Chemistry 2. Inorganic Chemistry- The study of all substances that do not contain carbon. Example: H 2 O (Water)

6 Branches of Chemistry 3. Physical Chemistry- the study of the properties, changes, and relationship between energy and matter

6 Branches of Chemistry 4. Analytical chemistry- the identification of the components and composition of materials.

6 Branches of Chemistry 5. Biochemistry- the study of substances and processes occurring in living things. Example: Photosynthesis

6 Branches of Chemistry 6. Theoretical Chemistry- the use of mathematics and computers to design and predict the properties of new compounds.

The Feces Question: 5 chemists from each of the 5 branches of chemistry are out hiking the Appalachian trail on a cold day. They come upon some fresh, steaming pile of dung…..GROSS!!! Did it come from a rabbit? A deer? A bear?! Or worse… a human being?!?! So the question remains….WHO DUNG IT?!?!?

With all the chemist abilities they will be able to figure this out!!!

12 Structure Determines Properties Everything is made of tiny particles called atoms and molecules. Chemists study these particles, looking at the kinds, numbers, structure, size which produce varying chemical and physical properties.

The Scientific Method 1. Observation 2. Formulate a Hypothesis 3. Experiment 4. State the results/theory Tro, Chemistry: A Molecular Approach13

Tro's "Introductory Chemistry", Chapter 1 14 Observation Acquiring information or data using your senses. Some observations are simple descriptions “The soda pop is a liquid with a brown color and a sweet taste. Bubbles are seen floating up through it.” Some observations compare a characteristic. “A 240-mL serving of soda pop contains 27 g of sugar.”

Tro's "Introductory Chemistry", Chapter 1 15 Hypothesis Making an educated guess based on your observations and previous knowledge: The sweetness of soda pop is due to the presence of  Sugar or  Aluminum

Tro's "Introductory Chemistry", Chapter 1 16 Experiments Test your hypotheses with a taste test: sugar and aluminum. Theory State your experimental findings. This is not the same as a scientific law. Sugar is sweet

Tro's "Introductory Chemistry", Chapter 1 17 Laws Typically a fact of nature, often a math constant/number and unit. Law of Conservation of Mass— “In a chemical reaction matter is neither created nor destroyed.” Speed of Light, E = mc 2, Dalton’s Gas Law, Universal Gas Constant, etc… Unlike California State laws, you cannot choose to violate a scientific law

Tro's "Introductory Chemistry", Chapter 1 18 Theories Explains how nature behaves. Newton’s Gravitational Theory: how an apple falls Dalton’s Atomic Theory: atoms look like… Darwin’s Theory of Evolution: we always change Einstein's Theory of Relativity: light is constant Used to predict future observations.

Tro's "Introductory Chemistry", Chapter 1 19 What’s the Difference Between a Law and a Theory? Laws: Very specific, “What will happen” often expressed in mathematical equations. Theories: Very general, “Why it will happen,” often includes many “Laws”

Classification of Matter States of Matter Physical and Chemical Properties Physical and Chemical Changes

Tro, Chemistry: A Molecular Approach21 Classification of Matter matter is anything that has mass and occupies space, Light, music, microwaves are not matter we can classify matter based on whether it’s solid, liquid, or gas

Tro, Chemistry: A Molecular Approach22 Classifying Matter by Physical State Fixed = keeps shape when placed in a container Indefinite = takes the shape of the container

Tro, Chemistry: A Molecular Approach23 Solids the particles in a solid are packed close together and are fixed in position though they may vibrate the close packing of the particles results in solids being incompressible the inability of the particles to move around results in solids retaining their shape and volume when placed in a new container, and prevents the particles from flowing

Tro, Chemistry: A Molecular Approach24 Crystalline Solids some solids have their particles arranged in an orderly geometric pattern – we call these crystalline solids salt and diamonds

Tro, Chemistry: A Molecular Approach25 Amorphous Solids some solids have their particles randomly distributed without any long-range pattern – we call these amorphous solids plastic glass charcoal

Tro, Chemistry: A Molecular Approach26 Liquids the particles in a liquid are closely packed, but they have some ability to move around the close packing results in liquids being incompressible but the ability of the particles to move allows liquids to take the shape of their container and to flow – however, they don’t have enough freedom to escape and expand to fill the container

Tro, Chemistry: A Molecular Approach27 Gases in the gas state, the particles have complete freedom from each other the particles are constantly flying around, bumping into each other and the container in the gas state, there is a lot of empty space between the particles on average

Tro, Chemistry: A Molecular Approach28 Classification of Matter by Composition matter whose composition does not change from one sample to another is called a pure substance made of a single type of atom or molecule because composition is always the same, all samples have the same characteristics matter whose composition may vary from one sample to another is called a mixture two or more types of atoms or molecules combined in variable proportions because composition varies, samples have the different characteristics

Tro, Chemistry: A Molecular Approach29 Classification of Matter by Composition 1)made of one type of particle 2)all samples show the same intensive properties 1)made of multiple types of particles 2)samples may show different intensive properties

Tro, Chemistry: A Molecular Approach30 Classification of Pure Substances substances that cannot be broken down into simpler substances by chemical reactions are called elements basic building blocks of matter composed of single type of atom substances that can be decomposed are called compounds chemical combinations of elements composed of molecules that contain two or more different kinds of atoms all molecules of a compound are identical, so all samples of a compound behave the same way most natural pure substances are compounds

31 Classification of Pure Substances 1)made of one type of atom (some elements found as multi- atom molecules in nature) 2)combine together to make compounds 1)made of one type of molecule, or array of ions 2)molecules contain 2 or more different kinds of atoms

Elements vs. Compounds Tro, Chemistry: A Molecular Approach32 Na Cl NaCl

Tro, Chemistry: A Molecular Approach33 Classification of Mixtures homogeneous = mixture that has uniform composition throughout every piece of a sample has identical characteristics, though another sample with the same components may have different characteristics atoms or molecules mixed uniformly heterogeneous = mixture that does not have uniform composition throughout contains regions within the sample with different characteristics atoms or molecules not mixed uniformly

34 Classification of Mixtures 1)made of multiple substances, but appears to be one substance 2)all portions of a sample have the same composition and properties 1)made of multiple substances, whose presence can be seen 2)portions of a sample have different composition and properties

Homogeneous vs. Heterogeneous Tro, Chemistry: A Molecular Approach35

Tro, Chemistry: A Molecular Approach36 Separation of Mixtures separate mixtures based on different physical properties of the components Physical change Centrifugation & Decanting Density EvaporationVolatility ChromatographyAdherence to a Surface FiltrationState of Matter (solid/liquid/gas) DistillationBoiling Point TechniqueDifferent Physical Property

37 Distillation

38 Filtration

Chromatography animation, separation based on weight Tro, Chemistry: A Molecular Approach39

Problem: You obtain a mixture of iron, sand, and salt. Describe how each substance can be separated using the separation techniques discussed. You will use more than one separation technique. You may need to add another substance. Tro, Chemistry: A Molecular Approach40

Turn in (1 per group) Tro, Chemistry: A Molecular Approach41 Group NamesTitleDate Observations Before: Safety: You must wear goggles. Include any other precautions. Procedure: Numbered List. You must be specific Observations After: Conclusions: Successful? Improvements?

Physical Changes Physical change is any change that do Does NOT result in a change in identity. Examples cutting wire, crushing a solid, gas expanding. Changes in state of matter is a physical change. Example: melting, boiling, freezing.

Physical Properties Physical properties can be observed or measured without altering the identity of a material. Example: color, texture, melting point, state of matter.

Chemical Properties Chemical Properties relates to a substances ability to undergo changes that alters its identity. Example a chemical’s reactivity.

Chemical Change Chemical change is when a substance is converted into different substance. Examples: milk souring, leaves changing color in the fall. The process CANNOT be reversed.

Signs of a Chemical Change 1.Color Change 2.Heat and/or light is produced 3.Bubbles form (gas) 4.A precipitate is produced (A precipitate is a solid)

Tro, Chemistry: A Molecular Approach47 Animation of physical and chemical change

Energy

Tro, Chemistry: A Molecular Approach50 Energy Changes in Matter changes in matter, both physical and chemical, result in the matter either gaining or releasing energy energy is the capacity to do work work is the action of a force applied across a distance a force is a push or a pull on an object electrostatic force is the push or pull on objects that have an electrical charge

Tro, Chemistry: A Molecular Approach51 Energy of Matter all matter possesses energy energy is classified as either kinetic or potential energy can be converted from one form to another when matter undergoes a chemical or physical change, the amount of energy in the matter changes as well

Tro, Chemistry: A Molecular Approach52 Energy of Matter - Kinetic kinetic energy is energy of motion motion of the atoms, molecules, and subatomic particles thermal (heat) energy is a form of kinetic energy because it is caused by molecular motion

Tro, Chemistry: A Molecular Approach53 Energy of Matter - Potential potential energy is energy that is stored in the matter due to the composition of the matter and its position in the universe chemical potential energy arises from electrostatic forces between atoms, molecules, and subatomic particles

Tro, Chemistry: A Molecular Approach54 Conversion of Energy you can interconvert kinetic energy and potential energy whatever process you do that converts energy from one type or form to another, the total amount of energy remains the same Law of Conservation of Energy

Tro, Chemistry: A Molecular Approach55 Potential to Kinetic Energy