Chemistry 1 Study Guide Midterm 2015

Transcription

1 NAME: PERIOD: Chemistry 1 Study Guide Midterm 2015 ** Use your notes, workbook, foldables or the internet! ** All notes can be retrieved from my website on my calendar if needed. **This is due on JANUARY 6th (B Day) and JANUARY 7th (A DAY) You will be graded on completion. This will be worth a TEST GRADE!** 1. Name and explain the five traditional areas of study for chemistry? 1) Organic Chemistry study of all chemicals containing carbon 2) Inorganic Chemistry study of chemicals (in general) that do not contain carbon 3) Biochemistry study of processes that take place in organisms 4) Analytical Chemistry area that focuses on the composition of matter 5) Physical Chemistry deals with the mechanism, the rate, and the energy transfer that occurs when matter undergoes a change 2. List and explain the steps of the scientific method? 1) Observation observe with five senses 2) Question question that needs to be answered well defined 3) Hypothesis prediction based on prior knowledge if/then statement 4) Experimentation make a plan to test, materials needed, conduct experiment (3 trials) 5) Results collect data, organize data into table/spreadsheets 6) Analyze/Conclude do results support your hypothesis, defend conclusion, suggest improvements 7) Repeat someone else should be able to repeat your experiment based on your plan and get the same results 3. Define quantitative and qualitative data. Give two examples of each. Qualitative description using adjectives (no numbers) color, texture, smell Quantitative data that is expressed with numbers temperature, melting point, mass 4. What is Chemistry? Study of matter and the changes it undergoes. 5. Define dependent and independent variables. Dependent (the one being measured) the variable used to determine the changes in response to independent variable. Independent the factor that is deliberately changed/manipulated/tested in the experiment You got this! Hard work and dedication will be rewarded!! 1

2 6. List 10 lab safety rules. (These you may have to look up online Flinn Safety Lab Rules unless you have your quiz from the beginning of the year or a great memory! =) 1.) Never dispense flammable materials near an open flame 2.) Eye protection should be worn at all times 3.) Keep long hair secured back 4.) Wear close toed shoes 5.) Chemical waste should be disposed of as instructed 6.) Horseplay/practical jokes are not allowed 7.) Pick up glass with tongs 8.) Loose, dangling clothing or jewelry should not be worn 9.) If splashed with acid use water to wash immediately 10.) Point open end of test tube away from all people 7. Convert the following to scientific notation: a = 3.98 x 10 5 b = 2.28 x 10 3 c. 1,599,000,000 = x 10 3 d. 135,000,000,000 = 1.35 x Convert the following to standard form: a. 1.5 x 10 5 = b. 3.5 x 10 9 = 3,500,000,000 c. 4.4 x 10 3 = 4,400 d x 10 3 = Explain the difference between a gas and a vapor. Gas matter that exist in that state at standard temperature/pressure Vapor matter that is turned into a gas by a process (heating) 10. Define and give two examples of intensive and extensive properties. Intensive property that depends on the type of matter hardness, density, color Extensive property that depends on the size of the sample mass, volume 11. Provide five examples of chemical changes and five examples of physical changes. Chemical changes bleaching hair, burning wood, cooking egg, rotting potato, rusting iron Physical changes cutting hair, chopping wood, mixing salt and water, freezing water, melting ice 12. Of the five examples above, which are reversible and which are irreversible? Reversible mixing salt and water, freezing water, melting water Irreversible cutting hair, chopping wood, all the chemical changes You got this! Hard work and dedication will be rewarded!! 2

3 13. List four clues that can tell us whether or not a chemical change has occurred. change in color transfer of energy production of gas (bubbling) formation of a precipitate (solid) 14. State the Law of Conservation of Matter. Matter can not be created or destroyed. 15. Explain how matter is conserved in a campfire. When wood burns moisture is released and vapors, also ash is produced and left behind. If you were able to capture all the moisture and vapors released, the mass would be the same as before. 16. Define homogeneous and heterogeneous mixtures. Homogeneous same composition throughout Heterogeneous components not evenly distributed (different throughout), two or more phases 17. Give three examples of homogeneous mixtures. vinegar olive oil sugar water air 18. Give three examples of heterogeneous mixtures. chocolate chip cookie chicken noodle soup concrete pizza You got this! Hard work and dedication will be rewarded!! 3

4 19. Draw a concept map for matter. 20. Greek philosophers believed all matter was composed of what four elements. Fire, air, water, earth 21. Explain how the cathode ray tube proved the existence of electrons. Cathode rays are electrically charged stream of electrons flowing through a glass tube. The ray was deflected towards a positively charged plate, proving they were negatively charged. 22. Who performed the cathode ray tube experiment? J.J. Thomson 23. Explain how the following scientists contributed to the atomic theory. a. Mosely current periodic table arranged in order of increasing atomic number b. Thomson discovered electrons and introduced plum pudding model c. Rutherford disproved the plum pudding model with the gold foil experiment, discovered the nucleus You got this! Hard work and dedication will be rewarded!! 4

5 d. Mendeleev developed first published periodic table arranged in order of increasing atomic mass e. Dalton used experimental results to propose that all matter is composed of atoms f. Democritus just had an idea that all matter was composed up of tiny, indivisible particles called atoms 24. Who developed this model and what did he call it? Label the model. J.J. Thomson; Plum Pudding Model red part is positively charged matter, and yellow circles represent electrons. (no nucleus in his model) 25. Oxygen has three isotopes. Oxygen 16, Oxygen 17, and Oxygen 18. The natural abundance for each is 99.76%, 0.037%, and 0.204% respectively. What is the atomic weighted mass for oxygen. Show all work. 16 x = x = x = = weighted atomic mass 26. Define Ionization Energy. Amount of energy required for an atom to lose an electron and form a cation. 27. Which element has the greater ionization energy of the following? Answers in blue. Mg or Cl Ag or I O or F 28. What is first ionization energy? second ionization energy? First energy required to remove the first electron (forming a cation) Second energy required to remove a second electron from a cation 29. What is electron affinity? Ability of an atom to gain an electron 30. Which element has the greater electron affinity? Answers in blue. Mg or Cl Ag or I O or F You got this! Hard work and dedication will be rewarded!! 5

6 31. What is atomic radius? Half the distance between two nuclei of identical atoms. 32. Which element has greater atomic radius? Mg or Ba S or Po F or Fr 33. Which element has the greater metallic character? Mg or Ba S or Po F or Fr 34. What is electronegativity? Tendency of an atom to attract electrons in a compound. 35. Which element has the greater electronegativity? Rb or Se Al or Cl F or I 36. What is the periodic law? The periodic law states that when elements are arranged in order of increasing atomic number that there is a periodic repetition of their chemical and physical properties. 37. Who was the first person to arrange a periodic table? Mendeleev 38. How is the modern day periodic table arranged? In order of increasing atomic number 39. What are the main three classes of elements and their properties? a. Metals good conductors of heat and electricity, malleable, ductile, shiny b. Nonmetals not non metals, generally poor conductors of heat and electricity (except Carbon), most are gases at room temperature, except Sulphur and Phosphorus which are solids, and Bromine which is a liquid. Solids are brittle. c. Metalloids Have properties of both, can mix them to increase metal properties. 40. Describe the following and give two examples of each: alkali metal Group 1 of periodic table metals that are very reactive, react with water to form an alkaline solution, not found in nature only in compounds, one valence electron and must lose it to become stable (Li, Na, K, Rb) alkaline earth metal Group 2 of periodic table metals that are reactive (not as much as alkalis), found in nature as compounds, two valence electrons and must lose both to become stable. (Be, Mg, Ca, Sr, Ba, Ra) halogen Group 7 on periodic table right next to noble gases. Have 7 valence electrons so needs to gain one more to be stable. Make up general class of compounds called salts. Name means born out of salt. You got this! Hard work and dedication will be rewarded!! 6

7 noble gas Group 8 on periodic table Have stable, full outer shell (valence contains 8 electrons)...not reactive (inert) due to being stable. (He, Ne, Ar, Kr, Xe, Rn) transition element Elements with electrons in their d orbitals. Transitioning from metals to nonmetals. Ag, Au, and Cu in this area. inner transition element Elements with electrons in their f orbitals. Used to be called rare earth elements, but that is misleading as some are very abundant. representative element any element with electrons in either the s or p orbitals. Display a wide range of physical and chemical properties. 41. Write out the electron configurations and the orbital diagrams for the following elements: *** u means up arrow and n means down arrow for the orbital diagrams *** Ni 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 8 1s 2s 2p 3s 3p 4s 3d 4p un un un un un un un un un un un un un u u Ti 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 2 1s 2s 2p 3s 3p 4s 3d 4p un un un un un un un un un un u u Rb 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 1s 2s 2p 3s 3p 4s 3d 4p 5s un un un un un un un un un un un un un un un un un un u 42. Write out the noble gas configurations for the following elements: Ac(89 e ) [Rn] 7s 2 5f 1 Pa (91 e ) [Rn] 7s 2 5f What is an ion? Give an example. An atom that has either lost or gain electron(s). Na + or O What is the difference between a cation and an anion? Cation is a positively charged ion that is formed when an atom loses electron(s). You got this! Hard work and dedication will be rewarded!! 7

8 Anion is a negatively charged ion that is formed when an atom gains electrons(s). 45. How are ionic compounds formed? Are they charged or neutral? Why? 46. LIst several properties of ionic compounds. 47. What are alloys? How are they useful? Give three examples. 48. Identify each crystalline structure below as either body centered cubic, face centered cubic or hexagonal close packed. 49. Round each measurement to three significant figures. a meters = 87.1 b meters = c meters = 630 (really only 2 sig. figs. but have to round it ) 50. Solve the following using the correct significant figures. a = 79.2 b = 17.3 c x 0.34 = 2.6 d x 0.70 = Convert 5 km per hour to meters per second using dimensional analysis. Show all work. 5km 1000m 1hr 1min You got this! Hard work and dedication will be rewarded!! 8

9 1hr 1km 60min 60sec so, divide 5000/3600 to get 1.39 m/sec 52. Convert 5 gallons to ounces. Show all work. 5gal 4qt 2pt 2c 8oz 1 1gal 1qt 1pt 1c Multiply across (all numerators) 5 x 4 x 2 x 2 x 8 = 640 Divide by denominators (which is just 1) so won t change the value. 5 gallons = 640 ounces 53. How many minutes are there in exactly one week. Show all work. 1 week 7 days 24hr 60min 1 1week 1day 1hr Multiply across (all numerators) 1 x 7 x 24 x 60 Divide by denominators (which is just 1) so won t change the value. 1 week = 10,080 min 54. In the lab, a unknown piece of metal is found to have a volume of 245 cm 3 and a mass of 612 g. Calculate the density and identify the metal from the table below. Metal Density Al 2.70 g/cm 3 Pb 11.4 g/cm 3 Au 19.3 g/cm 3 D = m/v so D = 612g/245 cm 3 = 2.50 g/cm 3 so must be aluminum. 55. A bar of silver has a mass of 68.0g and a volume of 6.48 cm 3. What is the density of silver? D = m/v so D = 68.0g/6.48cm 3 = g/cm 3 You got this! Hard work and dedication will be rewarded!! 9

10 56. Fill in the following table: Element Name Atomic Number Protons Neutrons Mass number Neon Bromine Francium You got this! Hard work and dedication will be rewarded!! 10