Notes
At 20 °C the vapor pressure of benzene is 75 torr, and the vapor pressure of toluene is 22 torr. Solutions in both parts of this question are to be considered ideal.
(a) A solution is prepared from 1.0 mole of biphenyl, a nonvolatile solute, and 49.0 moles of benzene. Calculate the vapor pressure of the solution at 20 °C.
(b) A second solution is prepared from 3.0 moles of toluene and 1.0 mole of benzene. Determine the vapor pressure of this solution and the mole fraction of benzene in the vapor.
Water is added to 4.267 grams of UF6. The only products are 3.730 grams of a solid containing only uranium, oxygen and fluorine and 0.970 gram of a gas. The gas is 95.0% fluorine, and the remainder is hydrogen.
(a) From these data, determine the empirical formula of the gas.
(b) What fraction of the fluorine of the original compound is in the solid and what fraction in the gas after the reaction?
(c) What is the formula of the solid product?
(d) Write a balanced equation for the reaction between UF6 and H2O. Assume that the empirical formula of the gas is the true formula.
2 HCOONa + H2SO4 ---> 2 CO + 2 H2O + Na2SO4
A 0.964 gram sample of a mixture of sodium formate and sodium chloride is analyzed by adding sulfuric acid. The equation for the reaction for sodium formate with sulfuric acid is shown above. The carbon monoxide formed measures 242 milliliters when collected over water at 752 torr and 22.0 °C (v.p. = 21 torr). Calculate the percentage of sodium formate in the original mixture.
Give the formulas to show the reactants and the products for FIVE of the following chemical reactions.
Example: A strip of magnesium is added to a solution of silver nitrate.
Mg + Ag+ ---> Mg2+ + Ag
1. equimolar amounts of trisodium phosphate and hydrogen chloride, both in solution, are mixed.
2. propene gas is mixed with bromine vapor.
3. solid aluminum nitrate is dissolved in water.
4. solutions of potassium iodide, potassium iodate, and dilute sulfuric acid are mixed.
5. a solution of tin(II) sulfate is added to a solution of iron(III) sulfate.
6. a suspension of copper(II) hydroxide is treated with an excess of ammonia water.
7. a saturated solution of calcium hydroxide is added to a solution of magnesium chloride.
8. solid silver sulfide is warmed with dilute nitric acid.
Ethyl iodide reacts with a solution of sodium hydroxide to give ethyl alcohol according to the equation: CH3CH2I + OH¯ <===> CH3CH2OH + I¯
The reaction is first order with respect to both ethyl iodide and hydroxide ion, and the overall-rate expression for the reaction is as follows: rate = k[CH3CH2I][OH¯]
What would you do in the laboratory to obtain data to confirm the order in the rate expression for either of the reactants?
There is a greater variation between the properties (both chemical and physical) of the first and second of a group or family in the periodic table than between the properties of the second and third members of the group. Consider as examples either the group containing nitrogen or the one containing oxygen. Select three properties and discuss the variation of these properties to illustrate the generalization expressed in the first sentence of the question.
Permanganate ion, MnO4¯, oxidizes sulfite ion to sulfate ion. The manganese product depends upon the pH of the reaction mixture. The mole ratio of oxidizing to reducing agent is two to five at pH 1, and is two to one at pH 13. For each of these cases, write a balanced equation for the reaction, and indicate the oxidation state of the manganese in the product containing manganese.
Solve the following problem:
| AgBr(s) <===> Ag+(aq) + Br¯(aq) | Ksp = 3.3 x 10¯13 |
| Ag+(aq) + 2 NH3(aq) <===> Ag(NH3)2+(aq) | K = 1.7 x 107 |
(a) How many grams of silver bromide, AgBr, can be dissolved in 50 milliliters of water?
(b) How many grams of silver bromide can be dissolved in 50 milliliters of 10 molar ammonia solution?
Molarity and molality are two ways of expressing concentration.
(a) Clearly distinguish between them.
(b) Indicate an experimental situation where expressing concentrations as molarity is particularly appropriate.
(c) Indicate an experimental situation where expressing concentration as molality is particularly appropriate.
Given the following data for graphite and diamond at 298 K.
S°(diamond) = 2.4 J/mole K
S°(graphite) = 5.7 J/mole K
DHf° CO2(from diamond) = - 395.3 kilojoules/mole
DHf° CO2(from graphite) = - 393.4 kilocalories/mole
Consider the change: C(graphite) ---> C(diamond) at 298 K and 1 atmosphere.
(a) What are the values of DS° and DH° for the conversion of graphite to diamond.
(b) Perform a calculation to show whether it is thermodynamically feasible to produce diamond from graphite at 298K and 1 atmosphere.
(c) For the reaction, calculate the equilibrium constant Keq at 298K
Quantitative chemical data are often based on arbitrary standards. Discuss this statement with the following data for fluorine
(a) The atomic weight of fluorine is 19.00
(b) E°, the standard electrode potential, is +2.65 volts for the half reaction: F2 + 2e¯ <===> 2 F¯
Return to AP Test Menu
Copyright © 1971 by College Entrance Examination Board and
Educational Testing Service. All rights reserved.