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Question: salt water is an example of Element Substance Homogeneous mixture *

Question: salt water is an example of Element Substance Homogeneous mixture * Heterogeneous mixture compound.

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Question: salt water is an example of Element Substance Homogeneous mixture *

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  1. Question: salt water is an example of Element Substance Homogeneous mixture * Heterogeneous mixture compound

  2. Sheldon wants Leonard to honor room mate agreement section 8 subsection 2b by using precisely no more than 172.5 cm3 of space for his visiting non-human guest (density of guest=2.3 lb / 1.2 quarts). Choose the best equation to find out if Leonard’s 4.11 pound non human guest, can stay

  3. a. 4.11 lb x 2.3 lb x 1.06 quart x 1 L x 1 mL = 7.9 x 10-3 cm-3 1.2 quart 1 L 1000 mL 1 cm3 Yes, non human guest is allowed. (units = lb2/cm3) b. 4.11 lb x 1.2 quart x 1 L x 1000 mL x 1 cm3 = 2000 cm3 2.3 lb 1.06 quart 1 L 1 mL (2.0 x 103 cm3) No, non human guest is not allowed. * (correct answer) • 1.2 quart x 1L x 1000 mL x 1 cm3 = 490 cm3/lb 2.3 lb 1.06 quart 1 L 1 mL Yes, non human guest is allowed. (wrong unit for volume) d. 1 x 2.3 lb x 1.06 quart x 1 L x 1 mL = 4.9 x 10-4 cm -3 4.11 lbs 1.2 quart 1 L 1000 mL 1 cm3 Yes, non human guest is allowed. (cm-3 not volume unit) e. None are correct. Leonard will veto the room mate agreement & will accept non human guest into the apartment regardless.

  4. For the following symbol 17O8 • 17 is the # of neutrons & protons • 8 is the number of protons • 17-8 = number of neutrons • Statements a and b are true. • a,b,c are true. *

  5. Given the periodic table, choose the oneincorrect statement. • Periods go horizontally across the table. Groups are vertical. • The alkaline earth metal elements are in group IA and the alkali metals start with Be and end with Ra. * (backwards IA alkali metal) • Noble gases consist of He to Rn and are very inert to chemical reaction. • Halogens consist of F,Cl,Br, I and At. • The chalcogens consist of group VIA.

  6. 38For the element Sr 87.62 (this is what you see in periodic table) • The number of protons = 38 & the number of electrons = 38. The number of neutrons = 87.62 - 38 • The element is in group IIA and has a charge of negative 2. (not true, +2) • Sr(NO3)2 is named strontium nitrate. • Statements a and c are true. * • Statements a,b are true.

  7. Al (s) + HCl  AlCl3 + H2 The coefficients are: • 1, 1, 1, 1 • 2,3,1,2 • 2,6,2,3* • 1,3,1,3 • 1,3,1,1

  8. The molecular weight of H2SO4 is: • MW=2(1.01) x 32.0 x 4(16.0) • MW= 1.01 + 32.0 + 16.0 • MW = 2(1.01) + 32.0 + 4(16.0) * • MW= 2(1.01) + 16.0 + 4 (8.0)

  9. Choose the one incorrect statement: 1 mole of the element Li has 6.02 x 1023 atoms of Li and weighs 6.94 grams 1 mole of Ca(OH)2 has 6.02 x 10 23 molecules of Ca(OH)2 and weighs [40.1+2(16.0+1.01)]= 74.12grams) 1 mole of SF6 has 4 x (6.02 x 1023) atoms of F and has 4 x 19.0 = 76 grams of F (6)incorrect 1 molecule of Ca(OH)2 weighs 74.12 amu 1 mole of N2 has 2 x (6.02 x 1023) atoms of N and 6.02 x 10 23 molecules of N2

  10. Choose the one best statement. 1 mole has 6.02 x 10 23 atoms of an element. A mole weighs the same as the atomic mass of the element in grams (ex: molar mass of Mg is 24.3 grams) 1 mole of a molecule has 6.02 x 10 23 molecules. 1 mole weighs the same as the molecular weight of the molecule in grams. (ex: molar mass of MgCl2 is[24.3 + 2(35.5)] grams) All statements are correct. best statement

  11. How many atoms of Cl is in 354.2 g of MgCl2 [FW (MgCl2) = 95.3 g] ? 95.3 g MgCl2 x 354.2 g MgCl2 x 6.02 x 1023 atoms Cl mol MgCl2 35.4 g Cl b. 354.2 g MgCl2 x 1 mol MgCl2 x 2 mol Cl x 6.02x1023 atoms Cl correct 95.3 g MgCl2 1 mol MgCl 2 1 mol Cl c. 354.2 g MgCl2 x 95.3 g MgCl2 x 1 mol MgCl2 x 6.02x1023atomCl 1mol MgCl2 2 mol Cl 1 mol Cl d. There is not enough information to answer this question – duh!

  12. For the reaction 2H2 + O2 2H2O, if you start with 2.0 grams of O2 [MW (H2) = 2.02, MW (O2) = 32.0, MW (H2O) =18.02] (Choose the one best statement.) a.grams(H2O)=2.0 g O2x 1mol O2 x 1 mol H2O x 18.02 g H2O formed 32.0 g O2 1 mol O2 1 mol H2O b.grams (H2)=2.0 gO2 x 1 mol O2 x 2 mol H2 x 2.02 g H2 (consumed) 18.02 g O2 1 mol O2 1 mol H2 c.moles (H2O)=2.0 g O2 x 1 mol O2 x 2 mol H2Ocorrect formed 32.0 g O2 1 mol O2 d. moles (H2)=2.0 g O2 x 1 mol O2 x 1 mol H2 (consumed) 32.0 g O2 1 mol O2 e. All statements are correct.

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