Solution of the variant 17 KR №1 - chemisty Shimanovich

Product description

The decision of the test No. 1 of option 17 of the collection of chemistry Shimanovich I.E.

(designed in Microsoft Word)

Tasks:

• Upon interaction of 3.24 g of a trivalent metal with an acid, 4.03 liters of hydrogen (NU) are released. Calculate the equivalent, molar and atomic mass of the metal.

• Write down the electronic formulas of atoms of elements with serial numbers 24 and 33, taking into account that the first has a "dip" of one 4s-electron to the 3d-sublevel. What is the maximum spin of d-electrons for atoms of the first and p-electrons for atoms of the second elements?

• The atomic masses of elements in the periodic table are continuously increasing, while the properties of simple bodies change periodically. How can this be explained? Give a motivated answer.

• What electrons of the boron atom are involved in the formation of covalent bonds? How does the valence bond method (VS) explain the symmetric triangular shape of the BF3 molecule?

• The reaction of ammonia combustion is expressed by the thermochemical equation:

4NH3 (g) + 3O2 (g) = 2N2 (g) + 6H20 (g); H = -1530.28 kJ.

Calculate the heat of formation of NH3 (g). Answer: -46.19 kJ / mol.

• Based on the standard heats of formation and the absolute standard entropies of the corresponding "substances, calculate the Gо298 of the reaction proceeding according to the equation:

C2H4 (g) + 3O2 (g) = 2CO2 (g) + 2H2O (g)

Is this reaction possible under standard conditions? Answer: -1331.21 kJ

• The equilibrium constant of the homogeneous system N2 + 3H2 2NH3 at a certain temperature is equal to 0.1. The equilibrium concentrations of hydrogen and ammonia are 0.2 and 0.08 mol / l, respectively. Calculate the equilibrium and initial nitrogen concentration. Answer: [N2] p = 8 mol / l; [N2] ref = 8.04 mol / l.

• Mixed 300 g of a 20% solution and 500 g of a 40% NaCl solution. What is the percentage of the resulting solution? Answer: 32.5%.

• How many grams of urea (NH2) 2CO should be dissolved in 250 g of water to raise the boiling point by 0.26 °? Ebullioscopic water constant 0.52 °. Answer: 7.5 g

• Make molecular and ion-molecular equations of interaction reactions in solutions between:

a) H2SO4 and Ba (OH) 2;

b) FeCl3 and NH4OH;

c) CH3COONa and HCl.

• Make up the ionic-molecular and molecular equations for the hydrolysis of a salt, the solution of which has:

a) alkaline reaction;

b) acid reaction