1. List the indicators of chemical change Formation of a gas, formation of a precipitate, change in color, absorbtion/release of heat 2. Define a. chemical changes – a change that alters the identity of a substance… examples rusting, fermenting, digesting b. Law of conservation of mass – mass or matter cannot be created or destroyed c. Independent variable- the variable that is intentionally manipulated by the experimentor d. Dependent variable- the variable that changes as a result of the changes to the independent variable e. Control- a group in which the independent variable is not manipulated, used for comparison f. Hypothesis- a possible explaination for observations, a testable idea g. Mole- the amount of particles in 12g of Carbon-12, also, the amount of substance having 6.022x1023 of any kind of particle h. half-life- the amount of time required for ½ of the mass of an isotope to decay i. metalloid- those elements that have properties of both metals and nonmetals j. Ionization Energy- the amount of energy required to remove one valence electron from an atom and form a positive ion k. Ionic Bond- a bond between a positive and negative ion, in which electrons were transferred between the two atoms and they are being held together by an electrostatic attraction 3. What is the mass number of an atom that contains 29 protons, 29 electrons, and 36 neutrons? the mass number would be 29 + 36 = 65 4. What experiment was done to discover the nucleus? Who performed it? What experiment was done to discover the electron? Who performed it? the gold foil experiment was done by Rutherford to discover the nucleus. Thomson did the cathode ray tube experiment to find the electron. (Thomson’s came first) 5. Draw Thomson’s model of the atom. plum pudding model…a positive zone filled with small, negative particles. 6. Which of the atoms listed are isotopes of the same element, how can you tell? a. 168 X d. 178 X b. 16 9 X e. 12 6 X X f. 147 X A and D are isotopes of the same element because they have the same atomic number and different mass numbers 7. Given the equation: X 24 He + 230 88 Rn What particle is represented by X? c. 26 10 X is representing 8. Given the equation: 234 90 Th 234 91 Pa 0 1 e + X What particle is represented by X? X is representing 234 92 U 9. What is the formula mass of W(SO4)2? 376 g/mol 10. Determine the number of moles present in 100g of AlCl3. there are 0.75 moles in 100g of AlCl3 11. What is the total number of sodium atoms in 10g of sodium? there are 2.6x1023 atoms in 10 g of sodium 12. How many molecules of CO are in 8 liters of CO? there are 2.2x1023molecules in 8L of CO 13. What is the mass of 2.3x1024 molecules of KCl? the mass is 223g 14. Calculate the number of molecules in 50.0 grams of H2SO4 3.1x1023 molecules 15. What is the name of Group 17 elements? Group 18? Group 1? Group 2 Group 17 is known as the halogens, group 18 the noble gases, group 1 the alkali metals and group 2 the alkaline earth metals 16. What is the identity of an atom has the electron configuration 1s22s22p63s23p4.? Sulfur 17. What is the total number of valence electrons of an atom of iodine in the ground state? there are 7 valence electrons in an atom of iodine 18. Draw the Lewis dot structure of arsenic? draw As surrounded by 5 dots (there should only be 1 pair) 19. How many valence electrons are in an atom with the following configuration: 1s22s22p63s23p3 this atom (phosphorus) has a total of 5 valence electrons 20. What is the element with the largest atomic radius? smallest? largest = Fr, Smallest = F 21. When an electron in the excited state drops from n=4 to n=2, what color is the photon given off? blue light 22. How does an atom form a positive ion with a 3+ charge? anion with a 2- (two negative) charge? a 3+ charge is the result of losing 3 electrons, a 2- charge is a result of gaining 2 electrons 23. Write the electron configuration for a sodium cation (Na1+)? 1s22s22p6 24. What is the correct formula for the ionic compound formed between sodium and oxygen? Na2O 25. Which atoms are most likely to form covalent bonds? What happens to their electrons? nonmetals form covalent bonds by sharing unpaired valence electrons 26. Is the molecule NH3 polar or nonpolar? are the bonds in the molecule polar or nonpolar? NH3 is a polar molecule with polar bonds 27. Describe how the electrons are dealt with in a nonpolar covalent bond the electrons in nonpolar bonds are shared equally between the two atoms 28. According to VSEPR, what is the shape of the SF2 molecule? bent 29. How many electrons are shared in a double bond? four electrons are being shared 30. List the diatomic molecules: H2 N2 O2 F2 Cl2 Br2 I2 31. What do the letters in VSEPR stand for? Valence Shell Electron Pair Replusion 32. List the intermolecular forces from weak to strong London dispersion, dipoledipole, hydrogen bond 33. Write the formula for the following compounds a. Dinitrogen tetrahydride N2H4 b. Copper (II) carbonate CuCO3 c. Potassium phosphate K3PO4 Sulfurous acid H2SO3 iodine pentafluoride IF5 antimony tribromide SbBr3 hexaboron monosilicide B6Si barium iodate Ba(IO3)2 magnesium perchlorate Mg(ClO4)2 silver phosphate Ag3PO4 cobalt(III) nitrite Co(NO3)3 mercury(I) bromide HgBr chromium(III) oxide Cr2O3 chlorine dioxide ClO2 34. Name the following compounds a. FeO Iron (II) Oxide b. NO2 Nitrogen monoxide c. Co3(PO4)2 Cobalt (II) phosphate d. HBr hydrobromic Acid e. HClO3 Chloric Acid f. AuF Gold (I) Fluoride g. CrBr2 Chromium (II) Bromide h. AlPO4 Aluminum Phosphate i. KNO2 Potassium Nitrite j. CaCO3 Calcium Carbonate k. P4S5 Tetraphosphorus pentasulfide l. O2 Oxygen m. SeF6 Selenium Hexafluoride n. Si2Br6 Disilicon hexabromide 35. A compound has an empirical formula of CH2 and a molecular mass of 84g. What is its molecular formula? C6H12 36. Phentyfloroform contains 57.54% C, 3.45% H, and 39.01% F. What is its empirical formula? d. e. f. g. h. i. j. k. l. m. n. 57.54gC / 12= 4.795 mol / 2.05 = 2.33 x 3 = 7 3.45gH / 1 = 3.45 mol / 2.05 = 1.68 x 3 = 5 39.01gF / 19 = 2.05 mol / 2.05 = 1 x 3 = 3 C7H5F 37. What is the empiricial formula for N8H6? N4H3 38. What is the percent by mass of magnesium in magnesium oxide, Mg3P2? 54% 39. Balance the reaction and identify the reaction type a. C3H8 + O2 CO2 + H2O 1, 5, 3, 4..combustion b. C8H18 + O2 CO2 + H2O 2, 27, 8, 18..combustion c. NaCl + F2 NaF + Cl2 2, 1, 2, 1…single replacement d. H2 + O2 H2O 2, 1, 2 synthesis e. K + MgBr2 KBr + Mg 2, 1, 2, 1 single replacement f. FeCl3 + NaOH Fe(OH)3 + NaCl 1, 3, 1, 3 double replacement g. Ag2O Ag + O2 2, 4, 1 decomposition h. S8 + O2 SO3 1, 6, 4, synthesis.