Chemistry Unit 1: Heat, Sig Dig, Metrics, elements, Compounds and Mixtures

Atom: Smallest unit of matter

Made of smaller parts called subatomic particles

Protons are positively charged, they are found in the nucleus, and determine the atomic number of the atom

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Electrons are negatively charged, they are found around the nucleus and determine the charge of the atom

Neutrons are neutrally charged, they are found in the nucleus and determine the isotope of the atom

Elements: A pure substance containing only one kind of atom

An element cannot be separated into simpler materials _except during nuclear reactions)

Over 100 existing elements are listed and classified on the periodic table

Compounds: A pure substance containing two or more kinds of atoms (elements) in fixed ratios

The atoms are chemically combined in some way.

Compounds cannot be separated by physical means. Separating a compound requires a chemical reaction

The properties of a compound are usually different than the properties of the elements it contains. TRUE

Mixtures: Two or more elements or compounds NOT chemically combined

No reaction between substances TRUE

Mixtures can be uniform (homogeneous) and are known as solutions in a liquid state

Mixtures can also be non-uniform (heterogeneous)

Mixtures can be separated into their components by chemical means

Spinning to separate by mass is called Centrifugation

Evaporating the liquid to leave the solid compounds is called Crystallization

Evaporating the and condensing a liquid is called distillation

Separation by size through a differential medium is called filtration

Separation of solutes by mass, polarity, charge, or shape is called chromatography

The properties of a mixture are similar to the properties of it's components. TRUE

C,E,B,A,D

An alloy is a solution of metal

Negatively charged ions are called anions

An atoms having the same # of protons but different amounts of neutrons are referred to as an isotope

A molecule is a substance that is made up of a non-metal and non-metal joined together covalently

A pure substance that cannot be split into simpler substances by chemical means is known as an element

Cations are positively charged ions

A homogeneous mixture in water is commonly known as a solution

An ion is an atom that has lost or gained electrons

protons and neutrons make up the relative atomic mass of an element

The 2 pure substances are elements and compounds