Chapter 2 - Basic Chemistry
- 1. The Chemistry of Life Chapter 2
- 2. Chemistry All living things depend on chemistry ◦ The structure and function of all living things are governed by the laws of chemistry Why is it important to understand chemistry in biology? Biologists study chemistry because all living things are made of the same kinds of matter that make up nonliving things
- 4. Matter Everything in the universe is made of matter Matter is anything that occupies space and has mass Mass is the quantity of matter an object has
- 5. Elements and Atoms Elements are substances that cannot be broken down chemically into simpler kinds of matter Information about elements is summarized on a chart called the periodic table The simplest particle of an element that retains all of the properties of that element is an atom
- 7. The nucleus Nucleus – the central region that makes up the bulk of the mass of the atom ◦ Consists of: Protons – positively charged particles Neutrons – particles with no charge
- 8. Electrons Net electrical charge of an atom is zero Electrons – small, negatively charged particles ◦ Move around the nucleus at very high speeds ◦ Located in orbitals – regions around a nucleus that show the probable location of an electron Orbitals correspond to specific energy levels
- 9. Elements Atomic Number = number of protons in an element Mass Number = total number of protons and neutrons in the atom
- 10. Isotopes Atoms of the same element that have a different number of neutrons Average atomic mass of an element takes into account the relative amounts of each isotope in the element
- 11. PRACTICE In groups, we are going to practice drawing elements on white boards Group 1 – Draw and identify the element that has 6 protons, 6 neutrons, and 6 electrons Group 2 – Draw and identify the element that has 7 protons, neutrons, and electrons
- 12. PRACTICE Group 3 – 8 protons, neutrons, and electrons Group 4 – 15 protons, 16 neutrons, and 15 electrons Group 5 – 16 protons, neutrons, and electrons Group 6 – 11 protons, 12 neutrons, and 11 electrons Group 7 – 13 protons, 14 neutrons, and 13 electrons Group 8 – 19 protons, 20 neutrons, and 19 electrons Group 9 – 26 protons, 29 neutrons, and 26 electrons
- 13. Compounds Compounds are made up of atoms of two or more elements in fixed proportions ◦ Chemical formula shows the kinds and proportions of atoms of each element that forms a particular compound (Ex: H20) Compounds usually very different from the elements that form them ◦ Sodium – soft metal ◦ Chlorine – poisonous gas ◦ Sodium chloride – table salt
- 14. Compounds Most atoms are not stable in their natural state, so they tend to react with other atoms in different ways to become more stable Chemical bonds are the attractive forces that hold atoms together
- 15. Ionic Bonds Covalent Bonds Formed when one or Formed when electrons more electrons are are shared between transferred from one atoms atom to another ◦ Single, double, and triple bonds Ion – atom or molecule with an electrical charge Molecule – simplest part (Na+, Cl-) of a substance that retains all of the properties of that substance and can exist in a free state Chemical Bonds
- 16. Section 2 ENERGY
- 17. Energy All living things use energy Amount of energy in the universe stays the same Can change from one form to another Transfer of energy is very important in biology
- 18. Energy and Matter Energy – the ability to do work ◦ Occurs in various forms and one form of energy can be changed to another form Important forms of energy in biological systems ◦ Chemical, thermal, electrical, and mechanical
- 19. States of Matter The atoms and molecules in any substance are in constant motion The motion and spacing between atoms or molecules determine the substances state: solid, liquid, or gas
- 20. States of Matter
- 21. States of Matter http://www.harcourtschool.com/activity /states_of_matter/
- 22. Energy and Chemical Reactions Chemical Reaction – one or more substances change to produce one or more different substances ◦ Energy is absorbed or released when chemical bonds are broken and new ones are formed ◦ Living things undergo many thousands of chemical reactions every day
- 23. Energy and Chemical Reactions Reactants – substances or molecules that participate in a chemical reaction Products – substances that form in a chemical reaction
- 24. Energy and Chemical Reactions Metabolism – the sum of all the chemical reactions that occur in an organism ◦ Energy your body needs is provided by sugars, proteins, and fats found in foods ◦ Body continuously undergoes chemical reactions to break down stored energy from foods into substances your body can use for energy
- 25. Activation Energy Activation Energy – the amount of energy needed to start a chemical reaction Catalysts – chemical substances that reduce the amount of activation energy that is needed for a reaction to take place ◦ Enzymes – biological molecule that speeds up metabolic reactions without being permanently changed or destroyed
- 27. Section 3 WATER AND SOLUTIONS
- 28. Water and Solutions Chemical reactions of all living things take place in the watery environment of the cell Water has several unique properties that make it one of the most important compounds found in living things
- 29. Polarity Polar – compounds with an uneven distribution of positive and negative charges
- 30. Solubility of Water The polar nature of water allows it to dissolve polar substances, such as sugars, ionic compounds, and some proteins Water does not dissolve nonpolar substances such as fats like oil
- 32. Hydrogen Bonding The polar nature of water causes water molecules to be attracted to one another Hydrogen bond – the force of attraction between a hydrogen molecule with a partial positive charge and another atom or molecule with a partial or full negative charge
- 33. Cohesion Adhesion An attractive force that An attractive force holds molecules of a between two particles of single substance different substances together Cohesion and Adhesion
- 34. Capillary Action Attraction between molecules that results in the rise of the surface of a liquid when in contact with a solid Cohesion and Adhesion
- 35. Questions How are cohesion and adhesion similar? How are they different? How do they contribute to capillarity?
- 36. Density of Ice Solid water is less dense than liquid water ◦ This is opposite of all other substances Hydrogen bonding causes ice crystals to have large amounts of open space
- 37. Why is it important that ice is less dense than water? When bodies of water freeze, they freeze from the top down Ice insulates the water below from the cold air, which allows fish and other aquatic animals to survive under the icy surface
- 38. Solutions Solution – a mixture in which one or more substances are uniformly distributed in another substance ◦ Solute – substance dissolved in the solvent (may be ions, atoms, or molecules) ◦ Solvent – substance in which the solute is dissolved Sugar dissolved in water – which one is the solvent and which is the solute?
- 39. Solutions Solutions can be composed of various proportions of a given solute in a given solvent Concentration of a solution is the amount of solute dissolved in a fixed amount of the solution A saturated solution is one in which no more solute can dissolve
- 41. Solutions Aqueous solutions – solutions in which water is the solvent ◦ Important to living things Marine microorganisms spend their lives in the sea Most nutrients plants need are in aqueous solutions in moist soil Body cells exist in an aqueous solution and are filled with aqueous solution
- 42. Important Properties of Water Property What It Does/Means Importance Cohesion Water molecules stick Movement of water in plants, together surface tension Adhesion Water sticks to another capillarity substance High heat Absorb and release large Stabilizes global temps, keep capacity amounts of heat energy cells at even temps without a big change in temp Solvent Water can dissolve many Marine organisms, plant different substances nutrients, body cells
- 43. Acids and Bases What do the words acid and base mean?
- 44. Ionization of Water As water molecules move, they bump into each other Some of these collisions are strong enough to result in a chemical change One water molecule loses a proton while another gains a proton
- 46. Ionization of Water H3O+ : Hydronium Ion OH- : Hydroxide Ion Acidity or alkalinity is a measure of the relative amounts of hydronium ions and hydroxide ions dissolved in a solution
- 47. Acids Bases Number of hydronium Number of hydronium ions (H3O+ ) GREATER ions (H3O+ ) LESS than than the number of the number of hydroxide hydroxide ions (OH-) ions (OH-) Tend to have a sour taste Alkaline Bitter taste Acids and Bases
- 48. pH pH scale – scale for comparing the relative concentrations of hydronium ions and hydroxide ions in a solution Ranges from 0 to 14 Change in 1 pH unit is a 10-fold change in acidity or alkalinity
- 49. Buffers Buffers are chemical substances that neutralize small amounts of either an acid or a base added to a solution Control of pH is important for living systems Enzymes can function only within a very narrow pH range