ЗАДАЧИ 81-90 | Целевой экзамен по химии

To register for classes, receive information on courses, and obtain answers to the target exam, write to @himia_repetitor via direct message. 81. 41 g of sodium acetate was dissolved in 200 cm³ of water. Determine the mass fraction of salt in the resulting solution (the density of water is 1 g/cm³). 82. Determine the mass of acetic acid that can be obtained by oxidizing 224 dm³ of butane with oxygen in the presence of a catalyst if the yield is 85%. 83. Find the mass of acetic acid formed by oxidizing 11 g of ethanal if the yield is 60%. 84. What volume of water must be added to 200 cm³ of 60% acetic acid (solution density 1.063 g/cm³) to obtain a solution with a mass fraction of CH3COOH equal to 9.0%? 85. When evaporating a 20% sodium acetate solution, the mass of the solution decreased by 50 g and became 190 g. Determine the mass fraction of salt in the resulting solution. 86. An excess of sodium bicarbonate was applied to 90.6 cm³ of a 35% solution (density 1.05 g/cm³) of a monobasic saturated carboxylic acid. The volume of gas released was 10.08 dm³ (normal conditions). Establish the formula of the acid. 87. Indicate the amount (mol) of bromine that can attach to 1 mole of a triglyceride with the molecular formula C55H98O6. (The triglyceride is formed from residues of non-cyclic carboxylic acids). Write a possible structural formula for this triglyceride. 88. A mixture of ethyl formate and methyl acetate is present. The mass of the mixture is 7.4 g. Indicate the mass of potassium hydroxide required for complete hydrolysis of the mixture. 89. Complete hydrolysis of a triglyceride mixture with a sodium hydroxide solution yielded 32.2 g of glycerol and 318.5 g of carboxylic acid salts. Determine the molar mass of the original triglyceride mixture. 90. During the alcoholic fermentation of glucose, 1.12 dm³ of carbon dioxide was released (normal conditions). a) Write the equation for the reaction. b) Calculate the mass of ethyl alcohol formed during fermentation.