Matter and Change Properties of Matter

Objectives Students will be able to Define matter, property, and types of property. Differentiate between physical change and chemical change. Explain three states of matter. Compare and contrast between elements and compounds Define and explain mixtures and how to separate mixtures.

Properties of Matter sec. 2.1 What is matter? Matter is anything which has mass and volume (which takes up space). Ex- table, chair, laptop.

What is property? A property describes how an object or matter looks (shape & size), feels (texture), or acts. You use your sense of taste and smell to tell the difference between an orange and an strawberry.

What is property? Cont. 1 Properties describe matter.

Types of properties There are two basic types of properties. These properties are called Physical properties and Chemical properties.

Physical Properties A property that can be observed without changing the nature of the substance. Examples: –Mass - amount of matter in an object –Volume - amount of space an object occupies –Density - mass per unit volume

–Boiling Point - temperature at which a liquid's vapor pressure equals atmospheric pressure –Freezing Point - temperature at which a liquid changes into a solid

Example of Physical Properties Shininess - tendency of an object to reflect light without scattering it Conductivity - tendency to allow the flow of heat or electricity Ductility - ability to be stretched into wires Malleability - ability to be shaped

Find the 3 -5 physical properties of the followings:

Physical Properties measuring each of these physical properties will not alter the basic nature of the substance.

Chemical Properties A property that can be observed only if the substance undergoes a change into another substance. It changes the chemical nature of matter.

Examples Reactivity with air (oxygen), acid or with another element or compound to produce a different compound. Flammability

Intensive Versus Extensive Properties Physical properties of matter are categorized as either Intensive or Extensive.

Intensive Properties that do not depend on the amount of the matter present. Example: Color, odor, Malleability, Ductility, Conductivity, Hardness, Melting point, Freezing Point, Boiling Point, Density.

Intensive Properties Every sample of a given substance has identical intensive properties because they have the same composition

Extensive Properties Properties that do depend on the amount of matter present. Example: mass, weight, volume, length.

Physical change & Chemical Change Matter is constantly changing. When solid water (ice cube) melts it becomes liquid water. It doesn't turn into soil or macaroni. This is an example of a physical change.

Reversible and irreversible Physical changes can be classified as reversible or irreversible.

Reversible Change All physical changes that involve a change from one state to another are reversible. Example: Melting

Irreversible Change Cutting hair, filing nails, and cracking an egg are examples of irreversible physical changes.

Chemical Change Chemical changes are changing substances into other substances. Example: spoiling milk or burning toast.

Unlike physical changes, you cannot reverse chemical changes. You can melt ice to get water and freeze that water to get ice again. You cannot make milk unspoiled.

States of Matter There are three main phases of matter: gases liquids solids.

There is also a fourth phase, plasma. it exists at very high temperatures, and molecules in that state can behave very differently. Plasma will not be discussed here.

Solid Solid - when the material has a definite volume or size and distinct shape at a given temperature. The particles (atoms) in a solid are packed tightly together, as a result, solids are mostly incompressible.

Liquid The particles in liquid are in close contact with one another, but the arrangement of particles is not rigid or orderly. They are free to flow from one location to another.

Gas In a gas, the particles are relatively far apart and can move freely.

Mixture A mixture is a physical blend of two or more components. Examples: Chicken noodle soup, air.

Types of Mixture a) Heterogeneous Mixture: Composition is not uniform throughout. Examples: Chicken noodle soup

b) Homogeneous Mixture – The composition is uniform throughout. Another name is solution. Example: Olive oil, vinegar

Phase A phase is used to describe any part of a sample with uniform composition and properties. Heterogeneous mixture consists of two or more phases. Homogeneous mixtures has single phase.

Separating Mixtures 1. Filtration 2. Distillation 3. Evaporation

Filtration The process that separates a solid from the liquid in a heterogeneous mixture.

Distillation A process by which impurities are removed from the liquid. As liquid changes into vapor, impurities are left behind.

Evaporation A process by which liquid is converted into its vapor form.

Substance and Mixture A substance is pure and has definite composition. Can’t be broken down using physical process. A mixture is a combination of substances Can be separated by physical process.

Classify mixture or Substance 1. Table sugar 2. hot tea 3. table salt 4. vinegar 5. Water 6. Pure gold 7. Steel

Elements & Compounds Element – An element is the simplest form of matter that has a unique set of properties. There are more than 100 types of elements Examples: Oxygen, hydrogen

Compounds Compounds: A compound is a substance that contains two or more elements chemically combined in a fixed proportion. Example: oxygen and hydrogen chemically combined to form water.

Differences Between Elements & Compounds Compound can be broken down into simpler substances but the elements can not.

Process to Break Down Heating – if sugar is heated, it turns into carbon and water vapor Electrolysis – if electricity is passed through water, hydrogen and oxygen is produced.

Check What process is used to break down water?

Symbols and Formulas Symbols are used to represent elements such as O, H, Na, Cl. Formulas are used to represent compounds such as NaCl, KCl.

Chemical Reactions A process in which one or more substances are changed into others. reactant + reactant > product

Chemical Reaction 2 A substance at the start of the reaction is called reactant. A substance produced in the reaction is a product.

During a chemical change, the composition matter always change.

Recognizing Chemical Change Four possible clues: 1) Transfer of energy 2) A change in color 3) The production of a gas 4) The formation of a precipitate

Recognizing Chemical Change Possible clues: 1) Transfer of energy – energy stored in natural gas is used to cook food. 2) a change in color – test strip drip in urine, color change will occur

Recognizing Chemical Change 2 3) The production of a gas – formation of Carbon dioxide when acid is put on rock containing carbonate. 4) The formation of a precipitate – formation of soap scum while cleaning bath tub.

Conservation of Mass During any chemical reaction, the mass of the product is always equal to the mass of the reactant.

Conservation of Mass - Chemical Change Example – burning wood. Careful measurements show that the total mass of the reactant (wood and the oxygen consumed) equals the total mass of the products (carbon dioxide, water vapor, and ash).

Conservation of Mass - Physical Change Mass also hold constant during physical change. Example – when 10 grams of ice melt, 10 grams of liquid water is produced.

Law of conservation of mass The Law of conservation of mass states that in any physical change or chemical reaction, mass is conserved. Mass is neither created nor destroyed.

Questions Classify the following changes as physical or chemical change: A) Water boils B) Salt dissolves in water C) Milk turn sour D) A metal rusts

2. In a chemical reaction, how does the mass of the reactants compare with the mass of the products?

What is the main difference between physical changes and chemical changes?