Presentation on theme: "Chapter 1 – 3 The Foundations There are two fundamental concepts for chemistry – Matter is composed of various types of atoms – On substance changes to."— Presentation transcript:
Chapter 1 – 3 The Foundations There are two fundamental concepts for chemistry – Matter is composed of various types of atoms – On substance changes to another by reorganizing the way the atoms are attached to each other.
5 Volume – SI derived unit for volume is cubic meter (m 3 ) 1 cm 3 = (1 x 10 -2 m) 3 = 1 x 10 -6 m 3 1 dm 3 = (1 x 10 -1 m) 3 = 1 x 10 -3 m 3 1 L = 1000 mL = 1000 cm 3 = 1 dm 3 1 mL = 1 cm 3 1 L = 1 dm 3
Units to a Power How many m 3 is 1500 cm 3 ? 3 1500 cm 3 1 m 100 cm 1 m 100 cm 1 m 100 cm 3 1500 cm 3 1 m 100 cm3 3 =15 m 3
Uncertainty All measurements have some degree of uncertainty. The certain numbers and the uncertain numbers in a measurement are called the significant figures of a measurement.
Precision vs. Accuracy Accuracy – how close a measurement is with the true value Precision - how close a set of measurements are to each other
Significant figures & Dimensional Analysis Science fiction often uses nautical analogies to describe space travel. If the starship U.S.S. Enterprise is traveling at warp factor 1.71, what is its speed in knots? Warp 1.71 = 5.00 times the speed of light speed of light = 3.00 x 10 8 m/s 1 knot = 2000 yd/h exactly What is an exact number?
Classifying matter 3 states…what are they? What do we know about them?
Methods of separating mixtures Only a physical change- no new matter Filtration- separate solids from liquids with a barrier Distillation- separates because of different boiling points – Heat mixture – Catch vapor in cooled area Chromatography- different substances are attracted to paper or gel, so they move at different speeds up the paper Chromatography-
Chapter 2 – Atoms, Molecules, and Ions HISTORY Robert Boyle was the first “chemist”: – Performed quantitative experiments Lavosier – father or modern chemistry
THREE IMPORTANT LAWS Law of conservation of mass (Lavoisier): – Mass is neither created nor destroyed Law of definite proportion (Proust): – A given compound always contains exactly the same proportion of elements by mass
…the third law Law of multiple proportions (Dalton): – When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers – Dalton could not deduce absolute formulas, but found that each element consisted of a certain type of atom and that compounds were formed from specific combinations of atoms.
What do you know about Dalton? Which of the following statements regarding Dalton’s atomic theory are still believed to be true? I. Elements are made of tiny particles called atoms. II. All atoms of a given element are identical. III. A given compound always has the same relative numbers and types of atoms. IV. Chemical reactions change the way atoms are bound together. Atoms are thus changed!
Gay-Lussac/Avogadro & gases Gay-Lussac measured (under same conditions of T and P) the volumes of gases that reacted with each other. Avogadro’s Hypothesis: – At the same T and P, equal volumes of different gases contain the same number of particles
JJ Thompson – Postulated the existence of electrons using cathode-ray tubes – Determined the charge-to-mass ratio of an electron – The atom must also contain positive particles that balance exactly the negative charge carried by the electrons
Millikan – Performed experiments involving charged oil drops – Determined the magnitude of the electron charge – Calculated the mass of the electron
Rutherford – Explained the nuclear atom – Atom has a dense center of positive charge called the nucleus – Electrons travel around the nucleus at a relatively large distance
The modern atom The atom contains: Electrons – found in the electron cloud region; negative charge (1/2000 the size of a proton or neutron) Protons – found in the nucleus; positive charge equal in magnitude to the electron’s negative charge Neutrons – found in the nucleus; no charge; virtually same mass as a proton
The nucleus is: – Small compared with the overall size of the atom – Extremely dense; accounts for almost all of the atom’s mass “If the atom is the Houston Astrodome, then the nucleus is a marble on the 50-yard line.”
Atomic information Which is which? What does this mean? Z and A Atomic number Mass number Isotopes…what are they?
Bonds! Forces that hold atoms together in compounds Ionic Bonds: Bonds form due to force of attraction between oppositely charged ions Ion – atom or group of atoms that has a net positive or negative charge Cation – positive ion; lost electron(s) Anion – negative ion; gained electron(s) Polyatomic ions---memorize them!!!!!
More bonds! Covalent Bonds: – Bonds form between atoms by sharing electrons – Resulting collection of atoms is called a molecule Molecules can be represented in various ways. Some may or may not indicate the shape of the molecule. (shapes come in chapter 8)
The periodic table KNOW… – Locations of metals, nonmetals, metalloids – Group names – Most common ionic charge – Trends
Naming compounds Ionic AND molecular: What’s the difference? MgO MnO KMnO 4 NH 4 NO 3 Hg 2 Cl 2 Cr 2 O 3 KClO 4 NaClO 3 CaS K 2 S AlPO 4 CO 2 CO CCl 4 N 2 O 4 XeF 6 N 4 O 4 P 2 O 10
Now write formulas Sodium sulfite calcium iodide Lead (II) oxide Lead (IV) oxide Mercury (I) sulfide Barium chromate Aluminum hydrogen sulfate Cerium (IV) nitrite Sulfur dioxide diflourine monoxide nitrogen trichloride diphosphorus pentoxide
Try this! Which of the following compounds is named incorrectly? a) KNO 3 potassium nitrate b) TiO 2 titanium(II) oxide c) Sn(OH) 4 tin(IV) hydroxide d) PBr 5 phosphorus pentabromide e) CaCrO 4 calcium chromate
37 Hydrates are compounds that have a specific number of water molecules attached to them. BaCl 2 2H 2 O LiClH 2 O MgSO 4 7H 2 O Sr(NO 3 ) 2 4H 2 O barium chloride dihydrate lithium chloride monohydrate magnesium sulfate heptahydrate strontium nitrate tetrahydrate CuSO 4 5H 2 O CuSO 4