Understanding Basic Chemistry: Matter, Energy, and Chemical Reactions

1. Basic Chemistry

2. Matter • Matter – anything that occupies space and has mass • Physical change – doesn’t change chemically (like chopping veggies) • Chemical change – alters the composition (fermentation)

3. Energy • Energy – the ability to do work • Chemical – when bonds are broken • Electrical – movement of charged particles • Mechanical – from moving matter • Radiant – waves • The body uses energy released from breaking the bonds in ATP molecules (photosynthesis)

4. Composition of Matter • Elements • Fundamental units of matter that cannot be broken down into similar substances. • 96% of the body is made from four elements • Carbon (C) • Oxygen (O) • Hydrogen (H) • Nitrogen (N)

5. Atomic Structure • Atoms • Building blocks of elements • Nucleus • Protons (p+) • Neutrons (n0) • Outside of nucleus • Electrons (e-) Figure 2.1

6. Identifying Elements • Atomic number - # of protons (or electrons) • Atomic mass number - protons + neutrons

7. Isotopes and Atomic Weight • Isotopes - Have the same # of protons and vary in # of neutrons Figure 2.3

8. Isotopes and Atomic Weight • Atomic weight - Is basically the mass # (p+n) but takes into account the different isotope mass. *Hydrogen isotopes have atomic masses of 1, 2 & 3 causing the atomic mass to be 1.0079 instead of 1.

9. Radioactivity • Radioisotope – Isotope that is heavy & unstable. Needs to decompose to become stable • Radioactivity - Process of spontaneous atomic decay

10. Molecules and Compounds • Molecule – two or more like atoms combined chemically • Compound – two or more different atoms combined chemically. 2H + O = H2O

11. Energy Shells & Bonding - Atoms want their valence shell (outermost) filled with electrons. (inert) - When it isn’t filled, they lose, share or steal electrons forming bonds. (reactive)

12. Energy Shells & Bonding Reactive – lose, steal or share Inert - Full

13. Chemical Bonds • Ionic Bonds - Form when electrons are completely transferred from one atom to another (lost or stolen) • This forms Ions (Charged particles) • Anions are negative • Cations are positive PRESS TO PLAY IONIC BONDS ANIMATION

14. Chemical Bonds • Covalent Bonds – share electrons (single or double) Figure 2.6c

15. Examples of Covalent Bonds PRESS TO PLAY COVALENT BONDS ANIMATION Figure 2.6a–b

16. Polarity • Some atoms are better at attracting electrons than the other atoms in the molecule, causing polarity or charged poles. • Non-polar - neutral • Polar - Have a positiveand negative side Figure 2.7

17. Chemical Bonds • Hydrogen bonds - Weak chemical bonds that provides attraction between molecules. This helps keep structure.

18. Patterns of Chemical Reactions • Synthesis reaction (A+BAB) • Energy is absorbed • Decomposition reaction (ABA+B) • Chemical energy is released

19. Synthesis and Decomposition Reactions Figure 2.9a–b

20. Patterns of Chemical Reactions • Exchange reaction (ABAC+B) - both synthesis and decomposition reactions • Switch is made between molecule parts and different molecules are made Figure 2.9c