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Basic Chemistry Concepts. Structure and function of all living things are governed by the laws of Chemistry Understanding of Chemistry’s fundamental principles provides a better understanding of living things and how they function. Composition of Matter.

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Basic Chemistry Concepts

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Basic chemistry concepts

Basic ChemistryConcepts

Structure and function of all living things are governed by the laws of Chemistry

Understanding of Chemistry’s fundamental principles provides a better understanding of living things and how they function

Composition of matter

Composition of Matter

  • Everything in the universe is made of matter

  • Matter is anything that has mass and takes up space



  • Pure substances that cannot be broken down chemically into simpler kinds of matter

  • Periodic Table gives:

  • Atomic Number

  • Chemical Symbol

  • Atomic Mass

Basic chemistry concepts

  • Of more than 100 elements, fewer than 30 are important in living things

  • More than 90% of the mass of living things is composed of:

    • Oxygen (O)

    • Carbon (C)

    • Hydrogen (H)

    • Nitrogen (N)



  • Simplest particle of an element that retains all of the properties of that element

    • Basic building blocks of all matter

  • Contain 3 types of particles:

    • Protons

    • Neutrons

    • Electrons

The nucleus of an atom

The Nucleus of an Atom

  • The central core of an atom

  • Most of the mass is here

  • Contains two kinds of particles


      • All atoms of an element have the same number of protons

      • Number of protons = atomic number


      • Number of protons + neutrons = atomic mass

      • Same element with different neutrons: isotopes



  • Third type of atomic particle


  • Very small and move around the nucleus at very high speeds

  • Number electrons = number protons

Basic chemistry concepts

  • Electrons move in different energy levels

  • Each energy level can hold only certain # of electrons

    • 1st level: 2

    • 2nd and other outer levels: 8

  • A stable atom is one that has a full outer level



  • Pure substances that are made up of atoms of two or more elements that are chemically combined

    • Proportion of each kind of atom is fixed (for example, H2O: chemical formula)

Basic chemistry concepts

  • Compound properties (physical and chemical) are different from individual element properties

  • Elements tend to combine depending on number and arrangements of electrons

    • Working toward more stable state


Chemical reactions and bonds

Chemical Reactions and Bonds

  • Atoms undergo chemical reactions to become more stable

  • In reactions, chemical bonds are broken, atoms rearranged, and new bonds (or attachments) are formed

  • Metabolism: all of the chemical reactions that occur in an organism

  • Two types of chemical bonds:

    • Covalent Bonds

    • Ionic Bonds

Covalent bonds

Covalent Bonds

  • Two atoms SHARE one or more pairs of electrons

    • Most compounds in organisms have covalent bonds

    • A group of atoms held together by covalent bonds is called a molecule

Ionic bonds

Ionic Bonds

  • Formed by electrical attraction between two oppositely charged ions

    • Ion: atom or molecule with an electrical charge

Energy and chemical reactions

Energy and Chemical Reactions

  • Energy is required to make or break chemical bonds, at least for the reaction to begin

  • Chemical reactions that involve a net release of energy: exergonic reactions

    • May be used to do other work

  • Chemical reactions that involve a net absorption of energy: endergonic reactions

Catalysts in chemical reactions

Catalysts in Chemical Reactions

  • For many compounds, the amount of energy needed to start the reaction (called activation energy) is HIGH

  • Catalysts are chemical substances that reduce the amount of activation energy needed

    • With a catalyst, the reaction may proceed spontaneously or with only small amount of energy

  • Enzymes are important catalysts in living things

Chemical equations

Chemical Equations

  • Shows the changes occurring in a chemical reaction

    • Reactants are on the LEFT side

    • Products are on the RIGHT side



  • Mixtures in which one or more substances are UNIFORMLY distributed in another substance (example: sugar water)

    • Sugar is the solute (substance dissolved)

    • Water is the solvent (substance in which the solute is dissolved)

  • Aqueous solution: water is the solvent

    • Universally important in living things

Acids and bases

Acids and Bases

  • On ph Scale from 0-14

    • 0 = very acidic (more H+ ions)

    • 7 = neutral

    • 14 = very basic or alkaline (more OH- ions)

  • Buffers neutralize solutions (example of homeostasis in living things)

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