The decision of the test No. 1 of option 65 of the collection of chemistry Shimanovich I.E.
(formatted in Microsoft Word)

Tasks:

7. Express in moles:
a) 6.02 x 1022 C2H2 molecules;
b) 1.80 x 1024 nitrogen atoms;
c) 3.01 x 1023 NH3 molecules.
What is the molar mass of these substances?

29. The isotope of silicon-40 is formed when the nuclei of aluminum-27 atoms are bombarded by a-particles. Make the equation for this nuclear reaction and write it in abbreviated form.

47. Which of the elements of the fourth period - vanadium or arsenic - has more pronounced metallic properties? Which of these elements forms a gaseous compound with hydrogen? Motivate your answer based on the structure of the atoms of these elements.

69. What crystal structures are called ionic, atomic, molecular and metallic? What crystals of substances: diamond, sodium chloride, carbon dioxide, zinc - have these structures?

94. During the combustion of 11.5 g of liquid ethyl alcohol, 308.71 kJ of heat was released. Write the thermochemical equation for the reaction that produces water vapor and carbon dioxide. Calculate the heat of formation of C2H5OH (g). Answer: -277.67 kJ / mol.

110. At what temperature the equilibrium of the system will come: CH4 (g) + CO2 (g) = 2CO (g) + 2H2 (g); H = +247.37 kJ? Answer: ~ 961.9 K.

135. Calculate the equilibrium constant for the homogeneous system CO (g) + H2O (g) CO2 (g) + H2 (g) if the equilibrium concentrations of the reacting substances: [CO] p = 0.004 mol / l; [H2O] p = 0.064 mol / l;
[CO2] p = 0.016 mol / l; [H2] p = 0.016 mol / l. What are the initial concentrations of water and CO?
Answer: K = 1; [H2O] ref = 0.08 mol / l; [C0] ref = 0.02 mol / l.

152. For neutralization 31 cm3 0.16 N. alkali solution requires 217 cm3 of H2SO4 solution. What are the normality and titer of an H2SO4 solution? Answer: 0.023 n .; 1.127x10-3 g / cm3.

173. Calculate the crystallization temperature of a 2% ethyl alcohol solution C2H5OH. The cryoscopic constant of water is 1.86 °. Answer: -0.82 ° C.

195. Make up the molecular and ion-molecular equations of interaction reactions in solutions between:
a) CdS and HCl;
b) Cr (OH) 3 and NaOH;
c) Ba (OH) 2 and CoCl2.

205. The following substances were added to the Na2CO3 solution:
a) HCl;
b) NaOH;
c) (NO3) 2;
d) K2S.
In what cases will hydrolysis of sodium carbonate intensify? Why? Write down the ion-molecular equations of hydrolysis of the corresponding salts