1.) A compound is a thing that is composed of two or more (separate) elements.
2.) A compound cannot be separated easily, while its properties differ from where it originates from. It also is formed from chemical reactions.
3.) A pure substance, also known as chemical substance, is a material with constant composition and consistant properties.
4.) If a substance is not a pure substance, then it is an impure substance.
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In a chemical reaction, the difference between the potential energy of the products and the potential energy of the reactants is equal to the heat of the reaction<span>. This is, the net energy released or absorbed (change) during a chemical reaction is the sum of the potential energy of the products less the sum of the potential energy of the reactants.</span>
Answer:
detectives, police officers and occasionaly lawyers/attorneys.
Explanation:
Non essential officers, judges, district attorney investigators, federal agents, victums, witnesses and politics are not permited to enter crime scenes unless they can provide information and history about the event.
Mass number (A) =protons (p+) + neutrons(n°)
