The study of matter and the properties of matter Chemistry Part A Notes The study of matter and the properties of matter

What is Matter? Matter – anything in the universe that has mass and takes up space. Examples of matter- air, all liquids, and all solids.

What is NOT Matter? Two common forms of energy are not matter; Light Heat Others???

What is matter made of? Matter is made of tiny particles called atoms. Atoms also have mass and take up space.

States of Matter Matter can be a solid, liquid, or gas. Solid – atoms are packed tightly Liquid – atoms are spread apart and bump into each other Gas – atoms are really spread apart, move quickly and bounce off of each other

Types of Matter Matter can either be a pure substance or a mixture. Pure substances can either be elements or compounds. Mixtures can either be homogeneous or heterogeneous.

Elements An element is matter made of only one kind of atom. There are 115 known elements. Ninety elements are naturally occurring. The elements are organized according to their properties in the Periodic Table. Examples – Hydrogen, Carbon, Nitrogen, Calcium, Sodium, Oxygen http://www.privatehand.com/flash/elements.html

Compounds Compounds are 2 or more elements that are chemically combined. Compounds cannot be easily separated into their elements. Examples; H2O Water NaCl Salt C6H12O6 Sugar/Glucose

H2 N2 O2 The gases of hydrogen, nitrogen and oxygen naturally exist as compounds of 2 atoms of their element.

Mixtures Mixtures are made of different compounds that are mixed together. Mixtures can be easily separated into the original compounds. Homogeneous – substances evenly mixed Heterogeneous – substances not evenly mixed

Classification of Elements The elements are classified into 2 main groups; Sodium Gold Metals Copper Non-metals Sulfur

Metals Physical properties of metals: Luster – shiny, reflects light brightly Conductors – heat and electricity move through metals easily. Malleable – can be hammered into shape Ductile – can be drawn into wire High Density – heavy for their size

Non-Metals Physical Properties of non-metals; Dull – not shiny Do not conduct heat or electricity Brittle – break or shatter easily Low Density

The Periodic Table of the Elements In the Periodic Table the elements are organized by their chemical and physical properties. Rows or, Periods – the elements are identified with increasing numbers from left to right. Columns or, Groups – are elements that have many similar properties. Sometimes referred to as families.

Symbols for the 6 Main Elements Chemical symbol – shows the element made up of one kind of atom Know the symbols for these elements Element Symbol Sodium Chlorine Hydrogen Oxygen Carbon Nitrogen

Symbols Chemical symbol – shows the element made up of one kind of atom Know the symbols for these elements Element Symbol Sodium Na Chlorine Cl Hydrogen H Oxygen O Carbon C Nitrogen N

Chemical Formulas Chemical formula – shows the symbols for the elements in a compound Subscript – number written to the lower right of the symbol that shows the number of atoms in the compound Example – H2O – the subscript “2” means that there are 2 hydrogen atoms in the water compound, no subscript for oxygen means there is only 1 oxygen atom

Formulas for the 6 Main Compounds NaCl H2O C6H12O6 O2 CO2 N2

Acids and Bases The pH Scale

Physical vs. Chemical Properties of Matter Physical properties of matter can be observed and measured without changing the kind of matter being studied. Chemical properties of matter are not usually visible and, a change in the matter does occur.

Physical Properties of Matter These physical properties can be used to identify a substance; Melting point Boiling point Density (heaviness) Color pH

Chemical Properties of Matter Chemical properties can also help identify a substance. Chemical properties can only be seen when there is a chemical reaction. Burning Rusting Chemical Reactivity

The pH Scale pH is the amount, or measure, of the concentration of acids and bases.  pH is measured on a scale from 1 – 14 Acids have a pH between 1 – 6 Bases have a pH between 8 – 14

Neutral pH Neutral pH is when a solution is neither an acid or a base. The solution has a pH of 7. Pure water has a pH of 7.

Acidic Solutions  Strong acids are very dangerous. Acids are identified by their sour taste. The lower the pH number, the stronger the acid Many fruits, such as oranges and lemons, are mildly acidic.  Strong acids are very dangerous.

Basic Solutions Bases usually have a bitter taste and feel slippery when rubbed between your fingers. Soap and other cleaners are usually bases  Strong bases are also very dangerous.

pH Indicators Indicators are substances that change color to help determine whether a solution is an acid or a base. Common pH Indicators; Litmus Paper pH paper Phenolphthalein

Litmus Paper There are 2 types of litmus paper; Blue litmus paper turns red in acids. Stays blue in bases. 2. Red litmus paper turns blue in bases. Stays red in acids. 3. Turns purple in a neutral solution.

pH Paper pH paper can turn a series of colors, depending on the pH, to determine the pH.

Phenolphthalein Phenolphthalein turns pink in a strong base and stays clear in an acid.