Matter Properties & Changes

 Matter – anything that has mass and takes up space  Substance - matter that has a uniform and unchanging composition…also known as a pure substance Properties of Matter Substances

Pure substance or a mixture? Topic 1 Topic 1 Chemistry and Matter: Basic Concepts A substance is matter, either an element or compound, with the same fixed composition and properties. A sample of matter is either pure—made up of only one kind of matter— or it is a mixture of different kinds of matter.

A mixture is a combination of two or more substances in which the basic identity of each substance is not changed. Unlike pure substances, mixtures do not have specific compositions. Topic 1 Topic 1 Chemistry and Matter: Basic Concepts Pure substance or a mixture?

Comparison of a Compound and a Mixture Click in this box to enter notes. Copyright © Houghton Mifflin Company. All rights reserved. Go to Slide Show View (press F5) to play the video or animation. (To exit, press Esc.) This media requires PowerPoint® 2000 (or newer) and the Macromedia Flash Player (7 or higher). [To delete this message, click inside the box, click the border of the box, and then press delete.]

A physical change is a change in matter that does not involve a change in the chemical identity of individual substances. Examples of physical changes include: boiling, freezing, melting, evaporating, dissolving, and crystallizing. Topic 1 Topic 1 Chemistry and Matter: Basic Concepts Pure substance or a mixture?

Physical properties are characteristics that a sample of matter exhibits without any change in its identity. Topic 1 Topic 1 Chemistry and Matter: Basic Concepts Pure substance or a mixture?

Physical Properties of Matter  A physical property is a characteristic that can be observed or measured without changing the sample’s composition. Physical Properties Movie

Examples of Physical Properties  Melting point  Boiling point  Freezing point  Color  Odor  Hardness  Taste  Malleability  Ductility  Magnetism  Crystalline shape  Luster  Refractive Index

 Physical properties can be further described as being one of two types  Extensive properties are dependent upon the amount of substance present  For example, mass, which depends on the amount of substance there is, is an extensive property.  Length and volume are also extensive properties. Extensive and Intensive Properties Extensive and Intensive Properties

 Intensive properties are independent of the amount of substance present  For example, density of a substance (at constant temperature and pressure) is the same no matter how much substance is present.  Color is another example of an intensive property  Melting point, boiling point & freezing points are also intensive properties Extensive and Intensive Properties Extensive and Intensive Properties

Physical Changes  Changes which alter a substance without changing its composition, are known as physical changes.  An example is the crumpling of a sheet of aluminum foil.  While the foil goes from a smooth, flat, mirror- like sheet to a round, compact ball, the actual composition of the foil is unchanged—it is still aluminum

 Phase changes are another example of physical changes  When you encounter terms such as boil, freeze, condense, vaporize, or melt in your study of chemistry, the meaning generally refers to a phase change in matter. Physical Changes

Chemical Changes chemical change, the change of one or more substances into other substances. A chemical property always relates to a Another term for chemical change is chemical reaction. Topic 1 Topic 1 Chemistry and Matter: Basic Concepts

 The ability of a substance to combine with or change into one or more other substances is called a chemical property.  The ability of iron to form rust when combined with air is an example of a chemical property of iron  Similarly, the inability of a substance to change into another substance is also a chemical property. Chemical Properties of Matter

 A process that involves one or more substances changing into new substances is called a chemical change, which is commonly referred to as a chemical reaction.  The new substances formed in the reaction have different compositions and different properties from the substances present before the reaction occurred. Chemical Changes

All matter is made of atoms, and any chemical change involves only a rearrangement of the atoms. Atoms do not just appear. Atoms do not just disappear. This is an example of the law of conservation of mass, which says that in a chemical change, matter is neither created nor destroyed. It would be equally correct to call this the law of conservation of matter. Topic 1 Topic 1 Chemistry and Matter: Basic Concepts

 When a freshly exposed iron surface is left in contact with air, it slowly changes into a new substance, namely, the rust.  The iron reacts with oxygen in the air to form a new substance, rust. Chemical Changes

 When you encounter terms such as explode, rust, oxidize, corrode, tarnish, ferment, burn, rot, or dissolve in acid, the meaning generally refers to a chemical reaction in which reactant substances produce different product substances. Chemical Changes

Categories of Matter Mixtures & CompoundsMixtures & Compounds video clip

Elements, Compounds, & Mixtures  An element is a pure substance that cannot be separated into simpler substances by physical or chemical means.  Each element has a unique chemical name and symbol.  The chemical symbol consists of one, two, or three letters; the first letter is always capitalized and the remaining letter(s) are always lowercase.

Elements  Elements take up one block on the periodic table

Compounds  A compound is a combination of two or more different elements that are combined chemically.  Water, table salt, table sugar, and aspirin are examples of common compounds.  Unlike elements, compounds can be broken down into simpler substances by chemical means.

Compounds  The chemical symbols of the periodic table make it easy to write the formulas for chemical compounds.  For example, table salt, or sodium chloride, is composed of one part sodium (Na) and one part chlorine (Cl), and its chemical formula is NaCl.  Water is composed of two parts hydrogen (H) to one part oxygen (O), and its formula is H 2 O.

 A mixture is a combination of two or more pure substances in which each pure substance retains its individual chemical properties. Mixtures

 Mixtures themselves are classified as either heterogeneous or homogeneous.  A heterogeneous mixture is one that does not blend smoothly throughout and in which the individual substances remain distinct.  The sand and water mixture is an example of a heterogeneous mixture. Types of Mixtures

 A homogeneous mixture has constant composition throughout; it always has a single phase.  Homogeneous mixtures are also referred to as solutions.  An example of a homogeneous mixture would be salt water. Types of Mixtures

Comparison of a Solution and a Mixture Click in this box to enter notes. Copyright © Houghton Mifflin Company. All rights reserved. Go to Slide Show View (press F5) to play the video or animation. (To exit, press Esc.) This media requires PowerPoint® 2000 (or newer) and the Macromedia Flash Player (7 or higher). [To delete this message, click inside the box, click the border of the box, and then press delete.]

 The solid–solid solution known as steel is called an alloy.  An alloy is a homogeneous mixture of metals, or a mixture of a metal and a nonmetal in which the metal substance is the major component. Types of Mixtures

Separating Mixtures  Because the substances in a mixture are physically combined, the processes used to separate a mixture are physical processes that are based on the difference in physical properties of the substances.

Filtration  Heterogeneous mixtures composed of solids and liquids are easily separated by filtration.  Filtration is a technique that uses a porous barrier to separate a solid from a liquid.

Distillation  Most homogeneous mixtures can be separated by distillation  Distillation is a separation technique that is based on differences in the boiling points of the substances involved.

Crystallization  Crystallization is a separation technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance.

Chromatography  Chromatography is a technique that separates the components of a mixture (called the mobile phase) on the basis of the tendency of each to travel or be drawn across the surface of another material (called the stationary phase).  The separation occurs because the various components of the ink spread through the paper ant different rates.  Paper Chromatography Paper Chromatography Paper Chromatography

States of Matter  In fact, all matter that exists on Earth can be classified as one of these physical forms called states of matter.  Scientists recognize a fourth state of matter called plasma, but it does not occur naturally on Earth except in the form of lightning bolts.  The three main states of matter are: solid, liquid, & gas.

Solids  A solid is a form of matter that has its own definite shape and volume.  The particles of matter in a solid are very tightly packed; when heated, a solid expands, but only slightly.  Because its shape is definite, a solid may not conform to the shape of the container in which it is placed.

Solid Structure Click in this box to enter notes. Copyright © Houghton Mifflin Company. All rights reserved. Go to Slide Show View (press F5) to play the video or animation. (To exit, press Esc.) This media requires PowerPoint® 2000 (or newer) and the Macromedia Flash Player (7 or higher). [To delete this message, click inside the box, click the border of the box, and then press delete.]

Liquids  A liquid is a form of matter that flows, has constant volume, and takes the shape of its container.  The particles in a liquid are not rigidly held in place and are less closely packed than are the particles in a solid: liquid particles are able to move past each other.

Liquids  This allows a liquid to flow and take the shape of its container, although it may not completely fill the container.  Because of the way the particles of a liquid are packed, liquids are virtually incompressible. Like solids, liquids tend to expand when heated.

Liquid Structure Click in this box to enter notes. Copyright © Houghton Mifflin Company. All rights reserved. Go to Slide Show View (press F5) to play the video or animation. (To exit, press Esc.) This media requires PowerPoint® 2000 (or newer) and the Macromedia Flash Player (7 or higher). [To delete this message, click inside the box, click the border of the box, and then press delete.]

Gases  A gas is a form of matter that flows to conform to the shape of its container and fills the entire volume of its container.  Compared to solids and liquids, the particles of gases are very far apart.  Because of the significant amount of space between particles, gases are easily compressed.

Gases  The word vapor refers to the gaseous state of a substance that is a solid or a liquid at room temperature.  For example, steam is a vapor because at room temperature water exists as a liquid.

Gas Structure Click in this box to enter notes. Copyright © Houghton Mifflin Company. All rights reserved. Go to Slide Show View (press F5) to play the video or animation. (To exit, press Esc.) This media requires PowerPoint® 2000 (or newer) and the Macromedia Flash Player (7 or higher). [To delete this message, click inside the box, click the border of the box, and then press delete.]

Laws

Law of Conservation of Mass  Lavoisier concluded that when a chemical reaction occurs, mass is neither created nor destroyed but only changed.  Lavoisier’s conclusion became known as the law of conservation of mass. Law of Conservation of Mass Clip

Law of Conservation of Mass  In this law – mass is neither created nor destroyed – it is conserved  Basically that means what you start with has to equal what you end with  Mass reactants = Mass products

Example  Lets say that you have g of mercury (II) oxide. It is placed into a flask and heated until it is converted into liquid mercury and oxygen gas. If I get 9.26 g of liquid mercury, how much oxygen gas was created?

Example  First you need to write the reaction in word form  Mercury (II) oxide  mercury + oxygen  Now place the amounts under the reaction  Mercury (II) oxide  mercury + oxygen  (10.00 g) = (9.26 g) + x  Solve for x  X = 0.74 g of oxygen gas

Try this one…  A reaction between sodium hydroxide and hydrogen chloride gas produces sodium chloride and water. A reaction of g of sodium hydroxide with g of hydrogen chloride gives off g of water. What mass of sodium chloride is formed in the reaction? g sodium chloride

Here’s one that’s a little different…  Copper sulfide is formed when copper & sulfur are heated together. In this reaction 127 g of copper react with 41 g of sulfur. After the reaction is complete, 9 g of sulfur remains un reacted. How much copper sulfide was formed?

Example  First you need to write the reaction in word form  Copper + sulfur  copper sulfide  Now place the amounts under the reaction  Copper + sulfur  copper sulfide  127g + what goes here? = x  127g + 32g = x  Solve for x  X = 159 g of copper sulfide

Law of Definite Proportions  The elements that composed the compounds were always in a certain proportion by mass.  This principle is now referred to as the law of definite proportions.  Another way to say this is…water is always water is always water…

 The mass of the compound is equal to the sum of the masses of the elements that make up the compound.  The ratio of the mass of each element to the total mass of the compound is a percentage called the percent by mass. Law of Definite Proportions

Example  A compound is analyzed in the lab an found to contain 8.44 g C, 1.3 g H, and g O. What is the % composition of each element in the compound?  First we must find the total mass % = Part x 100 Whole

Example C = 8.44 g H = 1.30 g O = g Total = 20.00g Now find the % of each / g X 100 = 42.2% C 6.50% H 51.30% O We find that this compound is sucrose

Another Example  Now let’s say that Mr. Romano finds a mystery white powder in the cafeteria. He asks us to analyze the substance and tell him what it is.  We find that there is g of C, 32.5 g H, and g O. What is the % composition of the compound?

Another Example C = g H = 32.5 g O = g Total = g / g X 100 = 42.2% C 6.50% H 51.30% O What is the mystery white powder??? SUCROSE

 The law of multiple proportions states that when different compounds are formed by a combination of the same elements, different masses of one element combine with the same relative mass of the other element in a ratio of small whole numbers.  Ratios compare the relative amounts of any items or substances. Law of Multiple Proportions

 The two distinct compounds water (H 2 O) and hydrogen peroxide (H 2 O 2 ) illustrate the law of multiple proportions.  Both water & hydrogen peroxide are made up of hydrogen and oxygen, the difference is in their proportions.  When we compare the mass of oxygen in hydrogen peroxide to the mass of oxygen in water, we get the ratio 2:1. Law of Multiple Proportions