課程名稱︰普通化學甲
課程性質︰第一階段暑修課
課程教師︰林英智、何東英、陳振中
開課系所︰不限
考試時間︰07/05, 2005
試題 :
1. Explain the difference of the root mean square velocity, the most probable
velocity and the average velocity. (10%)
2. Pure carbon was burned in an excess of oxygen. The gaseous products were
CO2 72.0 mol%
CO 16.0 mol%
O2 12.0 mol%
How many moles of O2 were present in the initial reaction mixture for every
mole of carbon? (10%)
3. You are given a solid that is a mixture of Na2SO4 and K2SO4. A 0.205 g
sample of the mixture is dissolved in water. An excess of an aqueous
solution of BaCl2 is added. The BaSO4 that is formed is filtered, dried,
and weighted. Its mass is 0.298 g. What mass of SO4^-2 ion is in the
sample? What is the mass percent of SO4^-2 ion in the sample? What are the
percent composition by mass of Na2SO4 and K2SO4 in the sample (10%)
4. Consider a 5.430 g mixture of FeO and Fe3O4. You react this mixture with
an excess of oxygen to form 5.79 g Fe2O3. Calculate the percent by mass of
FeO in the original mixture (10%)
5. In a mass spectrometer, positive ioins are produced when a gaseous mixture
is ionized by electron bombardment produced by an electric discharge. When
the electric-discharge boltage is low, singly positive ions are produced
and the following peak are observed in the mass spectrum.
Mass(amu) Relative Intensity
32 0.3743
34 0.0015
40 1.0000
When the electric discharge is increased, still only singly charged ions
are produced, but now the peaks observed in the mass spectrum are:
Mass(amu) Relative Intensity
16 0.7500
18 0.0015
40 1.0000
What does the gas mixture consist of and what is the percent composition by
isotopes of the mixture? (10%)
6. Give the systematic name of each of the following compounds. (10%)
a. Na2SO4 b.KH2PO4 c.Fe(NO3)3 d.Mn(OH)2 e.NaOCl
7. Consider reactin copper (II) sulfate with iron. Two possible reactions can
occur, as represented by the following equation.
copper(II) sulfate(aq) + iron(s) → copper(s) + iron(II) sulfate(aq)
copper(II) sulfate(aq) + iron(s) → copper(s) + iron(III) sulfate(aq)
You place 87.7m: of a 0.500M solution of copper(II) sulfate ina beaker.
You then add 2.00 g of iron filings to the copper(II) sulfate solution.
After the reaction occurs, you isolate 2.27 g of coper. Which equation
above describes the reaction that occured? support your answer (10%)
8. Calculate the root mean swuare velocities of CH4 and N2 molecules at 273K
and 546K
9. Draw the distribution diagram of an acid HA if Ka = 1.0 X 10^-5 (10%)
10.The iron content of iron ore can be determined by titration with standard
KMnO4 solution. The iron ore is dissolved in HCl, and all the iron is
reduced to Fe^+2 ions. This solution is then titrated with KMnO4 solution,
producing Fe^3+ and Mn^2+ ions in acidic solution. If it required 38.37mL
of 0.0198KMnO4 to titrate a solution made from 0.6128 g of iron ore, what
is the mass percent of iron in the iron ore? (10%)
11.The Ostwald process for the commercial production of nitric acid involves
the following three step:
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
2NO(g) + O2(g) → 2NO2(g)
3NO2(g) + H20(l) → 2HNO3(aq) + NO(g)
a. Which reactions in the Ostwald process are oxidation-reduction reactions?
b. Identify the oxidizing agent and the reducing agent in each redox
reaction.
c. Consider the first step of the Ostwalf process. How much nitric acid
oxide, NO, can be produced from a mixture of 5.0 X 10^6 of ammonia and
5.0 X 10^7 g of O2? (10%)
12. Describe the procedure to separate a solution containing Ag^+, Ba^2+ and
Fe^3+ ions. Using selective precipitation method.
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