Introduction to Matter Physical Science Chapter 2

Matter Matter is anything that has mass and takes up space. All of the universe is made up of matter. Characteristics of matter are called properties. Some special physical properties of matter included: color, odor, size, shape, texture and hardness.

Physical Properties The general physical properties of matter are mass, weight, density and volume. A physical property is a characteristic of a substance that can be observed without changing the identity of the substance.

Chemical Properties Chemical properties describe how a substance changes into other new substances. Chemical properties include: Flammability Reaction with oxygen Electonegativity Reactivity

Classes of Matter Matter can be found in four categories: Mixtures: Glass of Lemonade with Ice Solutions: Lemonade Elements: H, or Hydrogen Compounds:H20, or Water

Elements A pure substance is a type of matter in which the following are true: all the particles are alike the same through out and does not separate always has the same physical properties An element is the simplest type of pure substance.

Elements and Atoms An atom is the basic particle from which all elements are made and the smallest part of an element that has all of the same properties. Chemical symbols are a way of representing elements using letters. Each symbol consists of one, two or three letters, for example, C for carbon.

Compounds Compounds are pure substances that are made up of two or more elements chemically combined in a set ratio. Compounds can only be separated into the individual elements through chemical reactions. Compounds are represented by chemical formulas.

Chemical Formulas Chemical formulas are combinations of chemical symbols that represent the elements that make up a compound. Chemical formulas tell us which elements are present and how many atoms of each element. Subscripts are used to tell how many atoms of each element are present. Subscripts are placed on the lower right of the chemical symbol.

Mixtures A mixture is made up of two or more substances that are together, but not chemically combined.

Properties of Mixtures The following three things are true about the substances in a mixture: not chemically combined, so the substances keep their own identities and properties can be present in any amount, they are not combined in a set ratio can also be separated by simple physical means such as filtration, evaporation, distillation or magnetism

Types of Mixtures Mixtures are classified according to how well they are mixed. There are two major classes of mixtures: Heterogeneous mixtures A mixture that does not appear the same throughout Ex. Salad Homogenous mixtures A mixture that appears to be the same throughout Ex. Glass of Lemonade

Measuring Matter Matter is measured in terms of its general physical properties including: Weight Mass Volume Density In science, the International System of Units (SI) or metric system is used to measure all properties of matter.

Mass & Weight Mass is the amount of matter in an object. The mass of an object is constant, it does not change with location. Mass only changes when matter is added or removed. The standard unit of matter is the kilogram (kg), but grams (g) and milligrams (mg) can also be used for smaller amounts.

Weight Another general property of matter is weight. Weight is the pull of gravity on an object’s mass. Because gravity changes with location, weight is a changeable property.

Gravity Gravity is the force of attraction between two objects. All objects exert a gravitational pull on other objects. The gravity is dependent upon the size of the objects and the distance between them. The larger the objects the greater the gravity. The larger the distance between the objects, the less the pull of gravity.

Weight & Gravity The pull of gravity on an object determines its weight. Therefore, as the pull of gravity decreases, so does an object’s weight. The formula for weight is Mass x Gravity = Weight The metric unit of weight is the newton, N.

Volume & Density Volume is the space an object takes up. The metric units of volume are the liter (L), milliliter (mL), and the cubic centimeter (cm3.) Density is defined as the mass per unit volume of an object. The formula for density is Density = Mass / Volume

Density All matter has density. Density can be used to identify the type of matter you are working with. The density of water is 1.0 g/mL. Finding the density of an object and determining if it is greater or smaller than water will tell you if the object will float.

Changes in Matter Matter can change in two different ways: Physical Change: any change that alters the form or appearance but does not change the substance into a different substance Chemical Change: A change in matter that produces one or more new substances with different properties than the original substance

Physical Changes in Matter Physical changes are divided into: Changes of state such as: changing a solid to a liquid or a liquid to a gas Changes in appearance include: dissolving, crushing, breaking or filtering a substance.

Chemical Changes Chemical changes are also called chemical reactions and must follow the law of conservation of mass. The law of conservation of mass states that matter can neither be created nor destroyed by a chemical reaction. Examples of chemical changes include: Combustion Electrolysis Oxidation Tarnishing

Matter & Thermal Energy In both physical and chemical changes a change in thermal energy occurs. Ex.. Burning a candle or bending a paper clip Thermal energy is the total energy contained in all the particles of an object. Temperature is a measurement of the thermal energy of an object or substance.

Changes in Thermal Energy Two kinds of changes in thermal energy can occur: Endothermic: a change in which energy is absorbed by the substance Ex. Melting ice Exothermic: a change in which energy is released by the substance Burning a marshmallow

Forms of Energy Energy can occur in several different forms. The forms of energy are: Kinetic Potential Chemical Electromagnetic Electrical Thermal

Kinetic & Potential Kinetic energy is the energy of motion, such as an airplane flying. All moving objects have kinetic energy, even the smallest atoms are vibrating in place and therefore have kinetic energy. Potential energy is stored energy or the energy an object has due to position or shape. An example of potential energy is a stretched rubber band.

Chemical Energy Chemical energy is a form of potential energy that is stored in the bonds between atoms. Chemical energy is released when a reaction occurs, breaking the bonds and releasing the energy in the form of thermal, electromagnetic, or electrical energy.

Electromagnetic Energy Electromagnetic energy is energy in the form of electromagnetic waves. Examples of electromagnetic energy include: Radio waves Light waves UV waves X-Rays

Electrical Energy Electrical energy is the transfer of electrical charges from one place to another. Electrical energy is carried by moving electrons and is more commonly called electricity. Any type of energy can be transformed into another type of energy through different physical and chemical changes of matter.