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Chemistry |! 103 |! Midterm |! Exam |!
with |! complete |! solutions
pre-class |! content |! will |! be |! covered |! in-depth |! during |! our |! whole |! class |! meetings: |!
- |! Correct |! answer |! ✔sometimes you |! need |! to |! complete |! 100% |! of |! the |! pre-class |! assignments |! correctly |! to |! get |! full |! credit. |! - |! Correct |! answer |! ✔false (90% |! correct |! completion |! for |! full |! credit) the |! correlation |! between |! atmospheric |! CO2 |! levels |! and |! average |! surface |! temperatures |! allows |! one |! to |! conclude: |! - |! Correct |! answer |! ✔c. |! there |! is |! an |! interesting |! correlation |! between |! temperatures |! and |! CO2 |! levels |! that |! should |! be |! further |! investigated (correlation |! does |! NOT |! = |! causation) which |! state(s) |! of |! matter |! take |! on |! the |! shape |! of |! their |! container? |! - |! Correct |! answer |! ✔gases |! and |! liquids (because |! they |! are |! fluid)
which |! statement |! below |! is |! false? |! - |! Correct |! answer |! ✔a. |! a |! substance's |! melting |! point |! and |! freezing |! point |! occur |! at |! the |! same |! temperature. b. |! solids |! and |! liquids |! are |! much |! denser |! than |! gases. |! c. |! neon |! remains |! a |! solid |! at |! higher |! temperatures |! than |! does |! argon. |! d. |! as |! the |! temperature |! of |! a |! substance |! increases, |! the |! atoms' |! speed, |! on |! average, |! increases. |! Correct |! answer: |! C which |! of |! the |! following |! samples |! can |! be |! described |! as |! compounds? |! - |! Correct |! answer |! ✔D. |! 2 |! and |! 3 |! (need |! 2 |! or |! more |! DIFFERENT |! atoms!) bubbles |! form |! in |! a |! pot |! of |! water |! at |! 100 |! degrees |! Celsius. |! Is |! this |! an |! example |! of |! a |! chemical |! or |! physical |! change? |! - |! Correct |! answer |! ✔Physical |! change |! (this |! is |! the |! evaporation |! of |! water) |! Some |! common |! physical |! changes |! include: |!
- |! Calcium |! Hydroxide |! - |! Correct |! answer |! ✔(look |! at |! the |! charges)
- |! MgCO
- |! NaNO
- |! Na3PO
- |! CaOH Is |! pure |! water |! a |! good |! conductor |! of |! electricity? |! - |! Correct |! answer |! ✔no what |! is |! needed |! for |! effective |! conductivity? |! - |! Correct |! answer |! ✔freely |! mobile |! ions do |! sugar |! solutions |! conduct |! electricity? |! - |! Correct |! answer |! ✔no |! (no |! ions |! are |! present) will |! a |! strong |! acid |! solution |! such |! as |! HCl |! (aq) |! light |! up |! a |! light |! bulb? |! - |! Correct |! answer |! ✔Yes, |! it |! will |! conduct |! electricity will |! a |! weak |! acid |! solution |! (such |! as |! acetic |! acid) |! light |! up |! a |! light |! bulb? |! - |! Correct |! answer |! ✔Yes, |! it |! will |! conduct |! electricity (however, |! it |! is |! very |! dimly |! lit)
will |! a |! weak |! base |! solution |! (such |! as |! ammonia) |! light |! up |! a |! light |! bulb? |! - |! Correct |! answer |! ✔yes, |! it |! will |! conduct |! electricity (however, |! just |! like |! the |! weak |! acid, |! it |! is |! very |! dimly |! lit) consider |! a |! "lead-208" |! atom. |! What |! is |! the |! atomic |! number |! of |! this |! atom? |! - |! Correct |! answer |! ✔ 82 -mass |! number |! (A) |! is |! on |! top |! (# |! of |! neutrons |! and |! protons) atomic |! number |! (Z) |! is |! on |! bottom |! (# |! of |! protons |! and |! electrons) what |! is |! the |! nuclide |! symbol |! for |! an |! atoms |! with |! 27 |! electrons |! and |! 31 |! neutrons? |! - |! Correct |! answer |! ✔58Co 27 (27+31=58) (27 |! on |! bottom) Fluorine |! is |! a |! halogen. |! Halogens |! often |! react |! to |! form |! anions |! of |! charge |! -1. |! how |! many |! electrons |! and |! protons |! are |! found |! in |! a |! fluoride |! anion? |! - |! Correct |! answer |! ✔ 9 |! protons |! and |! 10 |! electrons if |! the |! electron |! cloud |! were |! the |! size |! of |! Camp |! Randall |! stadium, |! then |! the |! nucleus |! would |! have |! the |! size |! of: |! - |! Correct |! answer |! ✔a |! marble
3. |! S= |! +
What |! is |! the |! molar |! mass |! (in |! g/mol) |! of |! magnesium |! hydroxide? |! Mg(OH)2 |! - |! Correct |! answer |! ✔58. solve: |!
- |! Mg= |! 24.31 |! g/mol |! |! O= |! 16.00 |! g/mol |! x |! H= |! 1.008 |! g/mol |! x
- |! add |! it |! all |! together
- |! do |! 4 |! sig |! figs |! with |! molar |! mass! how |! many |! sig |! figs |! will |! there |! be |! in |! the |! answer |! to |! the |! following |! calculation? |! (10.00 |! x |! 34.1)/(0.0012 |! x |! 2.5469)? |! - |! Correct |! answer |! ✔ 2 |! sig |! figs which |! of |! the |! following |! statements |! are |! FALSE? |! - |! Correct |! answer |! ✔1. |! an |! object |! with |! a |! 100-pm |! radius |! would |! be |! observable |! without |! any |! magnification.
- |! an |! object |! with |! a |! 100-mm |! radius |! would |! be |! observable |! without |! any |! magnification. |!
- |! there |! are |! 1,000,000,000 |! nanometers |! in |! one |! meter. |!
- |! there |! are |! 10^-3 |! mL |! in |! one |! L. |!
- |! there |! are |! one |! million |! micrograms |! in |! a |! gram ANSWER: |! 1 |! and |! 4 please |! select |! the |! numeric |! value |! that |! makes |! this |! statement |! true: |! 1 |! centimeters |! = |! _______ |! kilometers |! - |! Correct |! answer |! ✔10^- which |! of |! the |! following |! statements |! is |! true? |! - |! Correct |! answer |! ✔ 1 |! km^3= |! 1,000,000,000 |! m^ is |! argon |! best |! described |! as |! a |! solid, |! liquid, |! or |! gas |! at |! 63 |! K? |! - |! Correct |! answer |! ✔solid is |! argon |! best |! described |! as |! a |! solid, |! liquid, |! or |! gas |! at |! 203 |! K? |! - |! Correct |! answer |! ✔gas the |! melting |! point |! of |! a |! substance |! is |! the |! temperature |! at |! which |! it |! changes |! from |! a |! solid |! to |! a |! liquid. |! Based |! on |! your |! PhET |! demo |! observations, |! estimate |! the |! approximate |! melting |! point |! of |! neon: |! - |! Correct |! answer |! ✔20-30 |! K based |! on |! your |! PhET |! demo |! observations, |! estimate |! the |! approximate |! melting |! point |! of |! argon: |! - |! Correct |! answer |! ✔75-85 |! K
the |! "plum |! pudding" |! model |! suggests |! that: |! - |! Correct |! answer |! ✔all |! alpha |! particles |! should |! pass |! directly |! through |! the |! atom |! undeflected Rutherford's |! model |! of |! the |! atom |! suggests |! that: |! - |! Correct |! answer |! ✔a |! small |! number |! of |! alpha |! particles |! are |! strongly |! deflected |! by |! the |! positively |! charged |! nucleus. Use |! the |! values |! you |! calculated |! in |! questions |! 4 |! and |! 5 |! to |! calculate |! the |! ratio |! of |! the |! diameter |! of |! a |! nucleus |! to |! the |! diameter |! of |! an |! atom |! - |! Correct |! answer |! ✔ 1 |! : |! 20, Chlorine |! has |! two |! stable |! isotopes, |! 35Cl |! and |! 37Cl. |! Since |! the |! atomic |! weight |! of |! chorine |! is |! 35.453, |! which |! is |! the |! more |! abundant |! isotope? |! - |! Correct |! answer |! ✔35Cl Naturally |! occurring |! gallium |! contains |! two |! isotopes: |! 69Ga |! (60.11%) |! and |! 71Ga |! (39.89%). |! Estimate |! the |! atomic |! weight |! of |! gallium |! to |! three |! significant |! figures. |! Do |! not |! include |! units. |! - |! Correct |! answer |! ✔69. how |! to |! solve: |! 69(0.6011) |! + |! 71(0.3989)= |! 69. 3 |! sig |! figs= |! 69. elements |! along |! a |! ___________ |! in |! the |! periodic |! table |! share |! chemical |! characteristics. |! - |! Correct |! answer |! ✔column
row answer: |! column magnesium |! belongs |! to |! the |! _________ |! family. |! - |! Correct |! answer |! ✔alkaline |! earth |! metals the |! halogen |! in |! teh |! second |! periodic |! table |! row |! is: |! - |! Correct |! answer |! ✔fluorine the |! noble |! gas |! in |! the |! 5th |! periodic |! table |! row |! is: |! - |! Correct |! answer |! ✔xenon according |! to |! the |! periodic |! table, |! potassium |! and |! nitrogen |! have |! similar |! chemical |! properties. |! - |! Correct |! answer |! ✔false Which |! of |! the |! following |! chemical |! formulas |! is |! the |! correct |! representation |! of |! tetraphosphorus |! decaoxide? |! - |! Correct |! answer |! ✔P4O Write |! out |! the |! name |! of |! the |! compound |! that |! has |! the |! chemical |! formula |! PCl3. |!
- |! Correct |! answer |! ✔phosphorous |! trichloride. How |! many |! bonds |! are |! broken |! in |! the |! combustion |! of |! one |! methane |! molecule? |! - |! Correct |! answer |! ✔ 6 |! The |! balanced |! reaction |! for |! the |! combustion |! of |! methane |! is
After |! adding |! ____________ |! strontium |! ions |! a |! solid |! precipitate |! is |! first |! observed. |! - |! Correct |! answer |! ✔ 48 After |! adding |! ____________ |! phosphate |! ions |! a |! solid |! precipitate |! is |! first |! observed. |! - |! Correct |! answer |! ✔ 32 Which |! of |! the |! following |! statements |! are |! TRUE? |! Choose |! all |! that |! apply. |! - |! Correct |! answer |! ✔Single |! atoms |! of |! xenon |! will |! have, |! on |! average, |! a |! mass |! of |! 131.293 |! u. The |! molar |! mass |! of |! xenon |! is |! 131.293 |! g/mol. what |! is |! the |! molar |! mass |! of |! water |! (H2O)? |! - |! Correct |! answer |! ✔18. H= |! 1.008 |! x O=16. Below |! is |! a |! reaction |! used |! to |! create |! electronic-grade |! silicon |! nitride |! films. |! Which |! of |! the |! following |! statements |! are |! correct |! about |! this |! reaction? |! (Choose |! as |! many |! responses |! as |! you |! feel |! are |! correct.) 3 |! SiCl4(g) |! + |! 4 |! NH3(g) |! → |! Si3N4(s) |! + |! 12 |! HCl(g) |! - |! Correct |! answer |! ✔For |! every |! three |! molecules |! of |! SiCl4 |! reacted, |! four |! molecules |! of |! NH3 |! are |! consumed.
For |! every |! three |! moles |! of |! SiCl4 |! that |! react, |! twelve |! moles |! of |! HCl |! are |! produced. Remember |! from |! Module |! 2 |! that |! the |! empirical |! formula |! is |! the |! simplest |! whole- |! number |! ratio |! of |! atoms |! in |! the |! molecule. |! The |! molecular |! formula |! represents |! the |! actual |! atom-count |! in |! the |! molecule, |! and |! it |! is |! a |! whole-number |! multiple |! of |! the |! empirical |! formula. Which |! one |! of |! the |! following |! statements |! is |! true |! for |! benzene, |! C6H6? |! - |! Correct |! answer |! ✔Benzene's |! empirical |! formula |! is |! CH; |! its |! molecular |! formula |! is |! C6H6. Octaethylporphyrin |! is |! comprised |! of |! carbon, |! hydrogen, |! and |! nitrogen. |! The |! elemental |! ratio |! is |! (9 |! mol |! C) |! : |! (11.5 |! mol |! H) |! : |! (1 |! mol |! N). |! What |! is |! its |! empirical |! formula? |! - |! Correct |! answer |! ✔C18H23N
