Compounds and mixtures

Mixtures A mixture is a combination of elements and/ or compounds that HAS NOT formed a new substance and whose proportions can be changed without changing the mixtures identity. Mixtures may be homogeneous or heterogeneous.

Mixtures Homogeneous Individual parts are NOT visible. Examples- Sweet tea, milk, air, bronze, brass, blood Heterogeneous Individual parts ARE visible. Examples- Salad, pizza, concrete

compounds A compound is a substance produced when elements chemically combine and whose properties are different from each of the elements in it. Examples- water, salt, aspirin, vinegar

Mixtures vs compounds Physically combined Chemically combined Mixtures

Mixtures vs compounds Physically combined Easily separated Chemically combined NOT easily separated

Mixtures vs compounds Mixtures Compounds Physically combined Easily separated NO new substance is formed Chemically combined NOT easily separated Forms a new substance

Mixtures vs compounds Mixtures Compounds Physically combined Easily separated NO new substance is formed MAY be different Chemically combined NOT easily separated Forms a new substance ALWAYS the same

Mixtures vs compounds Mixtures compounds Physically combined Easily separated NO new substance is formed MAY be different May have different proportions Chemically combined NOT easily separated Forms a new substance ALWAYS the same Same elements/Same proportions

Mixtures vs compounds Mixtures compounds Physically combined Easily separated NO new substance is formed MAY be different May have different proportions Does NOT have chemical formula Chemically combined NOT easily separated Forms a new substance ALWAYS the same Same elements/ Same proportions DOES have chemical formula

Chemical Formulas A chemical formula tells which elements make up a compound, as well as how many atoms of each element are present.

COMPOUNDS are represented by chemical formulas. Each element is represented by its unique chemical symbol. The NUMBER of CAPITAL letters tells how many elements are in a compound. LOWER case letters must go with the capital letter before them. The number of atoms of each element (other than 1) is represented by a small number to the lower right of the chemical symbol (subscript). More than one molecule of a compound is denoted by a co-efficient placed in front of the chemical formula.

H20 H (hydrogen) 2 O (oxygen) 1 Total 3 Let’s Practice! H20 H (hydrogen) 2 O (oxygen) 1 Total 3

Fe2O3 Fe (iron) 2 O (oxygen) 3 Total 5

Hint ! Remember- The su