Unit 2 – Chapter 2 Chemistry

1. Unit 2 – Chapter 2Chemistry

2. Matter – ________________________________________. Mass - the amount of matter an object has. • ___________________________. Gravity has an impact on weight. • The same mass on the earth would weigh less on the moon because less gravity on moon.

3. Elements – _____________________ – cannot be broken down into simpler types of matter. Examples: oxygen, carbon, hydrogen, and nitrogen – these four make up more than 90% of the mass of all living things! Periodic Table : • Displays elements in an organized manner. • From left to right – general trend is toward larger sized atoms. • See page 31 in textbook.

4. See page 31 in textbook: Atomic Number = _____________________________. Atomic Mass = ___________________________________ ___________________________________. Atom – ______________________________that _______ _______________________.

5. Atomic Structure consists of: • _________= central core – consists of ______ (+) and _________ (0). NOTE: #of protons or atomic number determines the atom’s identity. 2. _________ (-) orbit in energy levels or “shells” around the nucleus. NOTE: # of protons = # of electrons to give an atom a net charge of zero.

6. 3. 1st Shell (closest to nucleus) – holds 2 electrons (e-)…..these are the lowest energy electrons. 4. Each shell after the 1st can hold up to 8 electrons(e-)…..higher energy e-’s. NOTE: In most elements, the outer shell is not filled. This determines the reactivity of the atom. See page 32 in textbook.

7. Compound – ________________________________ ______________. Exs.) water – H₂0, ammonia – NH₃, glucose – C₆H₁₂O₆.

8. Isotopes – ______________________________________ ________________________ it has. Ex.) C₁₂ and C₁₄ (radioactive and unstable)

9. Chemical Formula – shows the kind and proportion of atoms in a compound. Ex.) H₂0

10. Chemical Reaction– chemical bonds are broken, atoms rearranged, and new bonds formed.

11. Molecule – _____________________________________ _______________________________of the substance and can exist in a free state. Exs.) O₂, O3H₂O, CO₂, DNA, protein. See page 33 in book for bonding info:

12. Covalent Bonds – _____________________________ Ex.) H₂O – atoms are striving for stability

13. Ionic Bonds: Ion = atom with a + or – charge from ______________ _______________________. Ionic Bond – occurs when _______________________ _______________________. Ex.) NaCl – salt.

14. Energy – _____________or cause change. Energy can change forms. Ex.) electrical can change to radiant and thermal (light bulb). Free Energy – energy available to do work.

15. __________________– solid, liquid, gas….depends on the motion of molecules. Ex.) Water – temperature makes molecules move at different rates and turns water to solid, liquid, or gas. Energy and chemical reactions: CO₂ + H₂O ↔ H₂CO₃ ↑ ↑ ↑ ___________________

16. Activation Energy – energy needed to start a reaction. (see graph on page 37 in textbook). ExergonicReactions – involve a net _________________ _____________. Ex.) Sugar → CO₂ + water + energy. Endergonic Reactions – involve a net ________________ _____________. Ex.) CO₂ + water + sunlight → sugar.

18. Catalyst – _______________________________________ ____________________. Ex.) ENZYMES act as catalysts. (see enzyme deficiency on page 37 in textbook.

19. Reduction-Oxidation Reactions (REDOX reactions): • Oxidation – reactant __________________and takes on a positive charge. • Reduction – reactant __________________ and takes on a negative charge. • Ex.) Na⁺ + Cl⁻ → NaCl (ionic bond)

20. Solution – a mixture in which _________________ ________________________…..can be liquids, solids, or gases. Ex.) Blood = iron, water, oxygen, sugar, wastes Solute – a ____________________ in the solution. Solvent – a _____________________________________. Concentration of Solution – the amount of solute dissolved in a fixed amount of solution. Ex.) 2% saltwater = 2grams salt in 100ml water. Saturated Solution – _________________________ ___________________________….the solution is “saturated”.

21. Aqueous Solution – solutions in which _______________ _____________ …..very important to living things as we are made up of lots of different aqueous solutions. Exs.) blood, urine, lymph, spinal fluid, mucus.

22. Acids and Bases Dissociation of Water– force of attraction between water molecules cause them to break apart. Pure water is neutral - # of OH⁻ and H₃O⁺ ions are equal. Acid- ___________ions is greater than OH⁻ ions. Ex.) Hydrogen chloride gas in water: HCl↔ H⁺ +Cl⁻ H⁺’s make the water acid.

23. Bases (Alkaline) - #of _________is greater than H₃O⁺ ions. Ex.) Sodium Hydroxide dissolved in water: NaOH ↔ Na⁺ + OH⁻ OH⁻ ions make the water basic or alkaline. pH Scale – compares the relative concentrations of OH⁻ and H₃O⁺ in a solution. pH – change in 1 pH unit = tenfold change in acidity/alkalinity. See figure 2-10, page 42 in book.

24. Buffers – ________________________________________ ___________________________________________. Complex Buffering Systems – maintain pH values of your many body fluids and tissues. See figure 2-10 0n page 42 in your book.