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CHM151 |! / |! CHEM |! 151 |! / |! CHEM151 |!
Midterm |! Exam |! Rio |! Salado |! with |!
verified |! answers
Chemistry |! is |! the |! study |! of? |! - |! Correct |! answer |! ✔Matter Is |! the |! statement |! "Falling |! barometric |! pressure |! preceded |! the |! onset |! of |! bad |! weather." |! a |! hypothesis, |! theory, |! or |! a |! law? |! - |! Correct |! answer |! ✔Law Is |! the |! statement |! "All |! life |! on |! Earth |! has |! evolved |! from |! a |! common, |! primitive |! organism |! through |! the |! process |! of |! natural |! selection." |! a |! hypothesis, |! theory, |! or |! a |! law? |! - |! Correct |! answer |! ✔theory Is |! the |! statement |! "My |! truck's |! gas |! mileage |! has |! dropped |! significantly, |! probably |! because |! it's |! due |! for |! a |! tune-up." |! a |! hypothesis, |! theory, |! or |! a |! law? |! - |! Correct |! answer |! ✔hypothesis The |! mass |! of |! a |! lead |! pipe |! is |! 14 |! lb. |! Is |! this |! observation |! in |! the |! microscopic |! domain, |! macroscopic |! domain, |! or |! symbolistic |! domain? |! - |! Correct |! answer |! ✔Macroscopic |! domain
The |! mass |! of |! a |! certain |! chlorine |! atom |! is |! 35 |! amu. |! Is |! this |! observation |! in |! the |! microscopic |! domain, |! macroscopic |! domain, |! or |! symbolic |! domain? |! - |! Correct |! answer |! ✔Microscopic |! domain A |! bottle |! with |! a |! label |! that |! reads |! Al |! contains |! aluminum |! metal. |! Is |! this |! observation |! in |! the |! microscopic |! domain, |! macroscopic |! domain, |! or |! symbolic |! domain? |! - |! Correct |! answer |! ✔Symbolic |! domain According |! to |! one |! theory, |! the |! pressure |! of |! a |! gas |! increases |! as |! its |! volume |! decreases |! because |! the |! molecules |! in |! the |! gas |! have |! to |! move |! a |! shorter |! distance |! to |! hit |! the |! walls |! of |! the |! container. |! Does |! this |! theory |! follow |! a |! macroscopic |! or |! microscopic |! description |! of |! chemical |! behavior? |! - |! Correct |! answer |! ✔Microscopic Which |! of |! the |! following |! is |! a |! pure |! substance? |! - |! Correct |! answer |! ✔Table |! salt, |! water, |! baking |! soda Which |! of |! the |! following |! is |! a |! heterogeneous |! mixture? |! - |! Correct |! answer |! ✔oil |! and |! vinegar, |! salad |! dressing A |! 2.0-liter |! volume |! of |! hydrogen |! gas |! combined |! with |! 1.0 |! liter |! of |! oxygen |! gas |! to |! produce |! 2.0 |! liters |! of |! water |! vapor. |! Does |! oxygen |! undergo |! a |! chemical |! or |! physical |! change? |! - |! Correct |! answer |! ✔Chemical |! Change Which |! of |! the |! following |! is |! an |! example |! of |! a |! chemical |! change? |! - |! Correct |! answer |! ✔Burning |! of |! magnesium
If |! the |! density |! of |! iron |! is |! 7.9 |! g/cm3, |! how |! much |! volume |! would |! 5.00 |! kg |! of |! iron |! occupy? |! - |! Correct |! answer |! ✔ 633 |! mL If |! the |! density |! of |! mercury |! is |! 13.6 |! g/cm3, |! how |! much |! mass |! would |! be |! needed |! to |! fill |! a |! 3 |! L |! vessel? |! - |! Correct |! answer |! ✔ 221 |! g How |! many |! significant |! figures |! should |! be |! in |! the |! answer |! of |! the |! following |! problem? 2.105 |! + |! 3.14 |! = |! - |! Correct |! answer |! ✔Three How |! many |! significant |! figures |! should |! the |! answer |! of |! the |! following |! problem |! have? (5500.1/6776) |! x |! 63690.1 |! = |! - |! Correct |! answer |! ✔Four Accuracy |! is |! defined |! as |! how |! close |! a |! measured |! value |! comes |! to |! a |! _____. |! - |! Correct |! answer |! ✔true |! value Precision |! is |! defined |! as |! how |! _____ |! the |! measured |! values |! are |! to |! one |! another. |! - |! Correct |! answer |! ✔reproducible
An |! experiment |! requires |! you |! to |! make |! several |! measurements. |! Based |! on |! the |! values |! in |! the |! table |! below, |! what |! would |! be |! the |! best |! statement |! that |! represents |! the |! data |! set |! if |! the |! true |! value |! is |! 0.2135? |! A |! B |! C 0.2139 |! 0.2893 |! 0. 0.2130 |! 0.3210 |! 0. 0.2133 |! 0.2999 |! 0. 0.2135 |! 0.2998 |! 0.3715 |! - |! Correct |! answer |! ✔The |! measurements |! in |! Trial |! A |! are |! accurate |! and |! precise, |! Trials |! B |! and |! C |! are |! neither |! accurate |! nor |! precise. Which |! postulate |! of |! Dalton's |! theory |! is |! consistent |! with |! the |! following |! observation |! concerning |! the |! weights |! of |! reactants |! and |! products? |! When |! 100 |! grams |! of |! solid |! calcium |! carbonate |! is |! heated, |! 44 |! grams |! of |! carbon |! dioxide |! and |! 56 |! grams |! of |! calcium |! oxide |! are |! produced. |! - |! Correct |! answer |! ✔Atoms |! are |! neither |! created |! nor |! destroyed |! during |! a |! chemical |! change. To |! calculate |! the |! number |! of |! neutrons |! in |! an |! atom, |! you |! would |! subtract |! - |! Correct |! answer |! ✔mass |! number |! from |! atomic |! number. Isotopes |! of |! a |! given |! element |! have |! the |! same |! number |! of |! _______ |! but |! a |! different |! number |! of |! ________. |! - |! Correct |! answer |! ✔protons, |! neutrons Which |! statement |! about |! subatomic |! particles |! is |! NOT |! true? |! - |! Correct |! answer |! ✔Protons |! and |! neutrons |! have |! the |! same |! charge.
Which |! of |! the |! following |! statements |! is |! NOT |! true? |! - |! Correct |! answer |! ✔Ionic |! bonds |! form |! between |! two |! nonmetal |! elements. What |! is |! the |! total |! mass |! of |! hydrogen |! in |! C12H10O6? |! - |! Correct |! answer |! ✔10.08 |! amu Which |! contains |! the |! greatest |! number |! of |! moles |! of |! oxygen |! atoms: |! 1 |! mol |! of |! ethanol |! (C2H5OH), |! 1 |! mol |! of |! formic |! acid |! (HCO2H), |! or |! 1 |! mol |! of |! water |! (H2O)? |! - |! Correct |! answer |! ✔Formic |! acid Calculate |! the |! molar |! mass |! of |! nitric |! acid, |! HNO3. |! - |! Correct |! answer |! ✔63.013 |! g/mol Determine |! the |! number |! of |! moles |! of |! 0.1488 |! g |! of |! phosphoric |! acid, |! H3PO4. |! - |! Correct |! answer |! ✔1.518 |! x |! 10-3 |! mol Determine |! the |! percent |! of |! SO42- |! in |! Al2(SO4)3. |! - |! Correct |! answer |! ✔81.71% Determine |! the |! empirical |! formula |! for |! compound |! with |! the |! following |! percent |! composition: |! 43.6% |! phosphorus |! and |! 56.4% |! oxygen. |! - |! Correct |! answer |! ✔P2O Determine |! the |! molarity |! of |! 0.515 |! g |! of |! H2SO4 |! in |! 1.00 |! L |! of |! solution. |! - |! Correct |! answer |! ✔0.00525 |! M
Determine |! the |! molarity |! of |! 20.54 |! g |! of |! Al(NO3)3 |! in |! 1575 |! mL |! of |! solution. |! - |! Correct |! answer |! ✔0.0612 |! M Determine |! the |! molarity |! of |! 0.000889 |! g |! of |! glycine, |! C2H5NO2 |! in |! 1.05 |! mL |! of |! solution. |! - |! Correct |! answer |! ✔0.0113 |! M What |! is |! the |! mass |! of |! solute |! in |! 200.0 |! L |! of |! a |! 1.556 |! M |! solution |! of |! KBr? |! - |! Correct |! answer |! ✔3.703 |! x |! 10^4 |! g Calculate |! the |! mass |! of |! the |! solute |! 75.0 |! mL |! of |! 2.2 |! x |! 10-5 |! M |! H2SO4. |! - |! Correct |! answer |! ✔1.6 |! x |! 10^-4 |! g What |! is |! the |! molarity |! of |! HCl |! if |! 35.23 |! mL |! of |! a |! solution |! of |! HCl |! contain |! 0.3366 |! g |! of |! HCl? |! - |! Correct |! answer |! ✔0.2630 |! M What |! mass |! of |! HCl |! is |! contained |! in |! 45.0 |! mL |! of |! an |! aqueous |! HCl |! solution |! that |! has |! a |! density |! of |! 1.19 |! g |! cm-3 |! and |! contains |! 37.21% |! HCl |! by |! mass? |! - |! Correct |! answer |! ✔19.9 |! g The |! level |! of |! mercury |! in |! a |! stream |! was |! suspected |! to |! be |! above |! the |! minimum |! considered |! safe |! (1 |! part |! per |! billion |! by |! weight). |! An |! analysis |! indicated |! that |! the |! concentration |! was |! 0.68 |! parts |! per |! billion. |! Assume |! a |! density |! of |! 1.0 |! g/mL |! and |! calculate |! the |! molarity |! of |! mercury |! in |! the |! stream. |! - |! Correct |! answer |! ✔3.4 |! x |! 10^- 9 |! M
Balance |! each |! of |! the |! following |! equations |! according |! to |! the |! half-reaction |! method: |! H2O2(aq) |! + |! MnO4−(aq)⟶Mn2+(aq) |! + |! O2(g) |! (in |! acid) |! - |! Correct |! answer |! ✔5H2O2(aq) |! + |! 2MnO4−(aq) |! + |! 6H3O+(aq) |! ⟶ |! 2Mn2+(aq) |! + |! 5O2(g) |! + |! 14H2O(l) What |! is |! the |! mass |! of |! chlorine |! gas |! necessary |! to |! react |! with |! 12.0g |! of |! sodium |! metal, |! Na, |! to |! produce |! NaCl? |! - |! Correct |! answer |! ✔18.5 |! g What |! is |! the |! number |! of |! moles |! and |! the |! mass |! of |! Mg |! required |! to |! react |! with |! 7.50g |! of |! HCl |! and |! produce |! MgCl2 |! and |! H2? |! - |! Correct |! answer |! ✔2.50 |! g I2 |! is |! produced |! by |! the |! reaction |! of |! 0.5235 |! mol |! of |! CuCl2 |! according |! to |! the |! following |! equation: |! 2CuCl2 |! + |! 4KI⟶2CuI |! + |! 4KCl |! + |! I2. |! What |! is |! the |! mass |! of |! the |! I2 |! produced? |! - |! Correct |! answer |! ✔66.43 |! g What |! volume |! of |! 0.200 |! M |! hydrochloric |! acid |! solution |! can |! be |! prepared |! from |! the |! HCl |! produced |! by |! the |! reaction |! of |! 25.0g |! of |! NaCl |! with |! excess |! sulfuric |! acid? |! NaCl(s) |! + |! H2SO4(l)⟶HCl(g) |! + |! NaHSO4(s) |! - |! Correct |! answer |! ✔2.14 |! L A |! sample |! of |! 0.53g |! of |! carbon |! dioxide |! was |! obtained |! by |! heating |! 1.31g |! of |! calcium |! carbonate. |! What |! is |! the |! percent |! yield |! for |! this |! reaction? |! CaCO3(s)⟶CaO(s) |! + |! CO2(s) |! - |! Correct |! answer |! ✔92% In |! a |! laboratory |! experiment, |! the |! reaction |! of |! 3.0 |! mol |! of |! H2 |! with |! 2.0 |! mol |! of |! I2 |! produced |! 2.0 |! mol |! of |! HI. |! Determine |! the |! percent |! yield |! for |! this |! reaction |! - |! Correct |! answer |! ✔50%
Consider |! the |! titration |! of |! 15.00 |! mL |! of |! NaCl |! of |! unknown |! concentration |! with |! 20.22 |! mL |! of |! 0.2503 |! M |! AgNO3 |! to |! reach |! an |! endpoint. |! What |! is |! the |! concentration |! of |! the |! NaCl |! solution? |! AgNO3(aq) |! + |! NaCl(aq)⟶AgCl(s) |! + |! NaNO3(aq) |! - |! Correct |! answer |! ✔0.3374 |! M What |! volume |! of |! 0.08892 |! M |! HNO3 |! is |! required |! to |! react |! completely |! with |! 0.2352g |! of |! potassium |! hydrogen |! phosphate? |! 2HNO3(aq) |! + |! K2HPO4(aq)⟶H2PO4(aq) |! + |! 2KNO3(aq) |! - |! Correct |! answer |! ✔30.37 |! mL Calculate |! the |! heat |! capacity, |! in |! joules |! per |! degree |! C, |! of |! 28.4g |! of |! water. |! - |! Correct |! answer |! ✔ 119 |! J/°C How |! much |! heat, |! in |! calories, |! must |! be |! added |! to |! a |! 75.0 |! g |! iron |! block |! with |! a |! specific |! heat |! of |! 0.449 |! J/g |! °C |! to |! increase |! its |! temperature |! from |! 25 |! °C |! to |! its |! melting |! temperature |! of |! 1535 |! °C? |! - |! Correct |! answer |! ✔1.21 |! x |! 10^4 |! cal How |! much |! would |! the |! temperature |! of |! 200.0 |! g |! of |! water |! increase |! if |! 36.5 |! kJ |! of |! heat |! were |! added? |! - |! Correct |! answer |! ✔43.6°C An |! aluminum |! kettle |! weighs |! 1.05 |! kg. |! How |! much |! heat |! in |! joules |! is |! required |! to |! increase |! the |! temperature |! of |! this |! kettle |! from |! 23.0 |! °C |! to |! 99.0 |! °C? |! - |! Correct |! answer |! ✔7.2 |! x |! 10^4 |! J A |! 45g |! aluminum |! spoon |! (specific |! heat |! 0.88 |! J/g°C) |! at |! 24 |! °C |! is |! placed |! in |! 180 |! mL |! (180g) |! of |! coffee |! at |! 85 |! °C |! and |! the |! temperature |! of |! the |! two |! become |! equal. |! What
How |! much |! heat |! is |! produced |! by |! combustion |! of |! 125 |! g |! of |! methanol |! under |! standard |! state |! conditions? |! (Use |! the |! Standard |! Molar |! Enthalpies |! of |! Combustion |! table |! in |! Section |! 5.3 |! in |! your |! textbook) |! - |! Correct |! answer |! ✔2.83 |! x |! 10^3 |! kJ How |! many |! kilojoules |! of |! heat |! will |! be |! released |! when |! exactly |! 1 |! mole |! of |! iron, |! Fe, |! is |! burned |! to |! form |! Fe2O3 |! (s) |! at |! standard |! state |! conditions? |! (Use |! Appendix |! G |! in |! text.) |! - |! Correct |! answer |! ✔ 412 |! kJ Determine |! the |! enthalpy |! change |! under |! standard |! state |! conditions |! for |! SnO(s) |! + |! CO(g)⟶Sn(s) |! + |! CO2 |! (g). |! (Use |! Appendix |! G |! in |! text.) |! - |! Correct |! answer |! ✔2.8 |! kJ Determine |! the |! enthalpy |! change |! under |! standard |! state |! conditions |! for |! 2Al(s) |! + |! Fe2O3(s)⟶Al2O3(s) |! + |! 2Fe(s). |! (Use |! Appendix |! G |! in |! text.) |! - |! Correct |! answer |! ✔- 852 |! kJ
