ELEMENTS COMPOUNDS MIXTURES Composition of Matter Pure Substances

ELEMENTS, COMPOUNDS & MIXTURES

Composition of Matter Pure Substances • Materials are made of a pure substance or a mixture of substances. • A pure substance, or simply a substance, is a type of matter with a fixed composition. • A substance can be either an element or a compound.

Classification of Matter- anything that has mass and takes up space Atom- smallest unit of matter

Types of substances Elements Most simple, pure substance, one type of atom present O 2, Na, Fe, N 2

Composition of Matter 1 Elements • About 90 elements are found naturally on Earth. • More than 20 others have been made in laboratories, but most of these are unstable and exist only for short periods of time.

Types of substances Compound 1. Composed of 2 or MORE different atoms (combined by chemical reaction) Sugar- C 6 H 12 O 6 Salt- Na. Cl 2. Will exhibit different properties from the elements that make them up

Classification of Matter Mixtures 1. Made of more than one kind of material (several compounds, compounds and elements, or several elements)

Classification of Matter Mixtures 1. Made of more than one kind of material (several compounds, compounds and elements, or several elements) 3. 2 types: Heterogeneous Homogeneous

Atom, Element, Compound, Molecule? ? REMEMBER: An atom is the smallest unit of matter An element is made of ONE TYPE of ATOM A compound is a chemical combination of two of more DIFFERENT types of atoms

What is a Molecule A molecule is the smallest unit of a compound that retains all properties of that compound. Example: glass of distilled water One water molecule is that smallest unit of that compound SOME atoms cannot exist as an individual in a sample of matter. EXAMPLE: oxygen, nitrogen, chlorine

Representations of Atoms, Molecules and Compounds Atom- represented by a circle that is ONE color OR ONE pattern Compound- represented by TWO or more DIFFERENT colored circles, DIFFERENT size circles, OR DIFFERENT patterns in the circles But are ATTACHED together

Representations of Atoms, Molecules and Compounds cont. Molecule – Can be represented By two circles the same color, pattern, or two or more circles that DIFFERENT colors, sizes or patterns.

Element or compound? Look at the pictures below - is it an element or a compound? Element Compound

Chemical Symbols A Chemical symbol is an abbreviation of the name of an element. How are they written? Capital letter if only one letter. Only first letter capital if more than one letter Element Oxygen Chemical Symbol O Nitrogen N Hydrogen H Sodium Na

How to read a formula This is a subscript. H 2 0 It tells us how many atoms of that element exist in one molecule of that compound. Hydrogen is made of 2 H atoms and 1 O atom.

Compounds Have Formulas The formula tells you 1. elements in the compound 2. # of atoms of each element in the compound.

Chemical Formulas Each symbol in a formula represents an element. If only one atom of an element is present in the compound, no subscript is used. - If more than one atom of an element is used, then the symbol is followed by a number called a subscript.

Chemical Formulas - Examples Calcium Carbonate (chalk) – Ca. CO 3 Sodium Chloride (salt) – Na. Cl Acetysalicylic acid (aspirin) – C 9 H 4 O 8 Acetic acid (vinegar) – C 2 H 4 O 2

Types of substances Heterogeneous Mixtures 1. Not the same throughout 2. Large easily seen particles that can be separated out 3. Heterogeneous liquid mixtures known as suspensions Settles after standing 4. Tacos, salad, italian dressing, pebble/sand mixture

Heterogeneous Mixtures 6. Colloids Won’t settle out Cloudy-Scatters light Particles mix, don’t dissolve Milk, lotion, toothpaste

Types of substances Homogeneous Mixtures 1. Appears same throughout 2. Well mixed 3. Won’t settle upon standing, 4. Tiny unrecognizable particles 5. Type: Solutions

Homogeneous Mixtures Homogeneous Mixtures 7. Solutions a) One substance dissolved in another b) Tiny particles can’t be seen c) Best mixed d) Clear or transparent- light passes right through e) Bottled water, apple juice air

Homogeneous Mixtures 8. Metal Solutions a) Alloys- solid metal solutions b) Gold= copper and gold c) Brass= copper and zinc d) Sterling silver= silver and copper

Graphic Organizer Create a graphic organizer to show the relationship between the following terms: elements compounds homogeneous mixtures heterogeneous mixtures suspensions colloids solutions

What types of substances are on the front counter? Label each with the correct substance name Element? Compound? Heterogeneous Mixture: Suspension? Homogeneous Mixture: Solution? Homogeneous Mixture: Colloid?

Homework Write the following assignment into your agenda: E, C, M Worksheet