Solution of the variant 54 KR №1 - chemisty Shimanovich

Product description

The decision of the test No. 1 of option 54 of the collection of chemistry Shimanovich I.E.

(formatted in Microsoft Word)

Tasks:

• An excess of hydrochloric (hydrochloric) acid affected the solutions:

a) calcium bicarbonate;

b) hydroxoaluminum dichloride.

Write the equations for the reactions of these substances with HCl and determine their equivalents and equivalent masses.

• 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?

• What are the lowest and highest oxidation states of carbon, phosphorus, sulfur and iodine? Why? Draw up the formulas of the compounds of these elements corresponding to these oxidation states

• What chemical bond is called covalent? How can you explain the directionality of the covalent bond? How does the method of valence bonds (VS) explain the structure of a water molecule?

• When gaseous hydrogen sulfide and carbon dioxide interact, water vapor and carbon disulfide CS2 (g) are formed. Write the thermochemical equation for this reaction by calculating its thermal effect. Answer: +65.43 kJ

• The entropy decreases or increases during the transitions: a) water into steam; b) graphite to diamond? Why? calculate Sо298 for each transformation. Make a conclusion about the quantitative change in entropy during phase and allotropic transformations. Answer: a) 118.78 J / (mol • K); b) -3.25 J / (mol * K).

• The reaction proceeds according to the equation N2 + 3H2 = 2NH3. The concentrations of the substances involved in it were: [N2] = 0.80 mol / l; [H2] = 1.5 mol / L; [NN3] = 0.10 mol / L. Calculate the concentration of hydrogen and ammonia when [N2] = 0.5 mol / L. Answer: [NH3] = 0.70 mol / l; [H] = 0.60 mol / l.

• Calculate the molar and equivalent concentration of a 20% solution of calcium chloride with a density of 1.178 g / cm3, Answer: 2.1 M; 4.2 n

• Calculate the percentage concentration of an aqueous solution of sugar С12Н22О11, knowing that the crystallization temperature of the solution is -0.93 ° C. The cryoscopic constant of water is 1.86 °. Answer: 14.6%.

• Which of the substances: Al (OH) 3; H2SO4; Ba (OH) 2 - will interact with potassium hydroxide? Express these reactions with molecular and ionic-molecular equations.

• When mixing solutions A12 (SO4) 3 and Na2CO3, each of the salts taken is irreversibly hydrolyzed to the end with the formation of the corresponding base and acid. Draw up the ionic-molecular and molecular equations of the ongoing joint hydrolysis.