Matter –Anything that has mass and occupies space. 1 The basic unit of matter is called the atom. Figure 2-2 Isotopes of Carbon. Section 2-1. 2, 3 Atomic Nuclei contain protons and neutrons. Protons 1+ charge size 1 amu nucleus Neutrons 0 charge size 1 amu in nucleus
01 / 56Matter –Anything that has mass and occupies space
1 / 17
Télécharger la présentation
Matter –Anything that has mass and occupies space
Une image / un lien ci-dessous est fourni (tel quel) pour télécharger la présentation
Politique de téléchargement : le contenu du site vous est fourni TEL QUEL pour votre information et votre usage personnel ; il ne peut être vendu, concédé sous licence ni partagé sur d’autres sites sans l’accord de son auteur.Le contenu vous est fourni TEL QUEL, pour votre information et votre usage personnel uniquement.Téléchargez la présentation en cliquant sur ce lien.Lors du téléchargement, si vous ne parvenez pas à télécharger une présentation, l’éditeur a peut-être supprimé le fichier de son serveur.Pendant le téléchargement, si vous ne parvenez pas à obtenir une présentation, le fichier a peut-être été supprimé par l’éditeur.
An Element in the Periodic Table Section 2-1 6 • 6. Proton # = 6 : shown by the atomic number • Also, C atoms have 6 electrons: Since atoms are neutral, if you know proton #, you also know electron #! C 12.011
Figure 2-2 Isotopes of Carbon Section 2-1 • 7 Isotopes are forms of the same element that have the same number of protons but a different number of neutrons. Nonradioactive carbon-12 Nonradioactive carbon-13 Radioactive carbon-14 6 electrons 6 protons 7 neutrons 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons
10 Chemical compounds are groups of atoms held together by chemical bonds. Chemical compounds are more stable than individual atoms (except for noble gas atoms which have stable ---filled—valence electron shells. • Chemical compounds allow atoms to obey the “octet rule”. (2 electrons in the outer electron shell in H and He, but 8 for other elements.
11 Chemical formulas show the numbers of different kinds of atoms bonded together in a single formula unit of a compound • NaCl one Na ion bonded to one Cl ion • Why do we know it’s composed of ions? Because Na is a metal—an electron donor—and Cl is a nonmetal—an electron acceptor if a metal is present to give it an electron.
Figure 2-3 Ionic Bonding 13 Ionic bonds: attraction of negative ions to positive ions because a metal donates its electrons to a nonmetal atom, forming stable ions with complete valence shell octets. Section 2-1 Sodium ion (Na+) Chloride ion (Cl-) Sodium atom (Na) Chlorine atom (Cl) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1
18 Van Der Waals forces and dipole-dipole interactions hold atoms of nearby molecules together. • Occasionally, valence electrons are nearer one atom than the other in a covalent bond, creating areas partial charge. http://www.chem.unsw.edu.au/coursenotes/CHEM1/nonunipass/HainesIMF/images/dipoledipole.jpg
Lesson 3: Chapter 2 The chemistry of Life • Watch movie on water, then answer questions on the worksheet together in your lab group BEFORE beginning the lab. Teacher will select one worksheet for grading, by random drawing. • Complete water lab, then turn in one copy per lab group . Teacher will select one student’s report. • Discuss the water movie & labs, and complete the 2.2 guided reading questions 1—8 as a class. • Homework: guided reading & study workbook questions, pages 15—16, #9—21.
Section Outline Section 2-2 • 2–2 • Properties of Water, • the strangest and most important molecule on earth! http://www.wsi.nrcs.usda.gov/products/images/wq_drop.jpg
3. Water is a polar covalent molecule because: • More electronegative O atoms are bonded to less electronegative H atoms • O carries a δ- charge & H’s a δ+ charge • The shared electrons of each O—H covalent bond are more strongly attracted to the O • All of the above • None of the above
Strongest triple covalent bond • 2nd strongest double covalent bond • 3rd strongest single covalent bond • 4th strongest ionic bond • 5th strongest Hydrogen bonds • 6th strongest Dipole dipole interactions (polar molecules attracted δ+ to δ- ) OTHER than Hydrogen bonds • 7th strongest Van der Waals forces (hydrophobic • interactions of nonpolar compounds)
4. Which statement is True? • Hydrogen bonds are stronger than ionic bonds. • Attraction of the H in one water molecule to O in another is a Hydrogen bond • Hydrogen bonds are stronger than covalent bonds • Hydrogen bonds are the strongest bonds BETWEEN different neutral molecules. • Choices 2 and 5 are true
5. Cohesion is: • Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder • Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules
5. Adhesion (exhibited by water adhering to the spider web) is: • Attraction of δ+ and δ- atoms of water molecules to atoms or ions of other substances, like the glass in a graduated cylinder • Attraction of δ+ H and δ- O of water molecules atoms in adjacent water molecules
6. Water is cohesive (shown by water’s forming droplets)because: • δ+ H and δ- O atoms of water molecules are attracted to each other in the same molecule • δ+ H and δ- O atoms of water molecules are attracted to each other in adjacent molecules
8 In plants capillary action: • Draws water upwards from the roots into the leaves through thin tubes called xylem • Pulls sugar downwards from the leaves into the roots through thin tubes called phloem
10-1-09 Lesson on solutions and suspensions with homework correction slides Lesson on acids and bases Complete water labs & questions & acid/base questions. Tear off lab & questions through end page. Put rest back in notebooks. Homework: prep for a quiz on ch 2.1,2.2, tomorrow
Mixture: 2 or more substances combined but not chemically bonded. They can be separated without another chemical reaction (a physical separation). e.g., sand and water can be separated with a filter inks in markers can be separated with chromatography Salt can be removed from water by evaporating the water
11. World’s greatest solvent: water! • Water is known as the universal solvent because it can dissolve ionic compounds and polar covalent compounds. • Ionic and polar covalent compounds are hydrophillic (water loving) • Water can not dissolve nonpolar covalent compounds. • Nonpolar compounds are hydrophobic (water hating)
12. A suspension is a: • Homogeneous mixture • Heterogeneous mixture • Unstable (particles settle out over time) • Stable (a solution whose solutes do not settle out) • 2 and 3
Parts of Solutions: Solvent: more abundant—does the dissolving Solute: less abundant—gets dissolved
concentration Molarity (M) = # moles solute/#L solution 3 Moles/0.5 L = 6 M 1 mole NaCl = 58.4 g 29.2 g/0.25 L = 0.5 moles/0.25 L= 2M
Aqueous solutions can be neutral, acidic, or basic. These descriptions depend refer to the behavior of the solute when it is dissolved in water and to how this behavior alters the molar concentrations of these two ions in the aqueous solution: H+ protons OH1- hydroxide ions