CHEMICAL REACTIONS 1. 2014 BAZA (UMAN) The reaction of extinguishing the calcium oxide (whitewash/lime) is used in selfheating containers. A container with a little quantity of calcium oxide is placed between the two walls of glass, and in the perforation of capsule with water the following chemical reaction takes place: CaO + H 2 O Ca(OH) 2 + Q 1. Characterize this reaction (indicate the type) according to two criteria: a)... b)... 2. Fill in the schemes of the chemical reactions which illustrate the chemical properties of calcium oxide with corresponding formulas and coefficients: a) CaO + CO 2... b) CaO + HCl... 2. 2014 BAZA (UMAN) One of the domains in which is used the nitric acid is the preparation of nitrates, commonly used as fertilizers. Write down the spaces below the reactions of nitrates obtained according to following schemas, choose those substances below that reacts with nitric acid. Na 2 SiO 3, BaO, Cu(OH) 2, HCl 1. HNO 3 + base. 2. HNO 3 + salt 3. 2014 BAZA (REAL) Barium sulfate is the component which determines the bright white and a specialdensity of the paper used for printing banknotes, financial fees and valuabledocuments.write equations of obtaining reactions of barium sulfate in correspondance with each proposed interaction: 1) acid + oxide...... 2) oxide + hydroxide.... 3) hydroxide + salt..... 4) salt + salt..... 4. 2014 T1 (REAL) Magnesium nitrate fertilizer for plants effectively stimulate the photosynthesis processes and the formation of protein. Write reaction equations for obtaining magnesium nitrate, using as reagents: 1) a metal...... 2) an oxide.... 3) a base..... 4) a salt..... 5. 2014 T1 (UMAN) Yield worldwide sodium hydroxide are estimated at 45 million tonnes per year. select appropriate substances which will interact with the sodium hydroxide: CaO; ZnCl 2 ; KOH; HNO 3 and write down the reactions: 1) NaOH + acid... 2) NaOH + sare... 6. 2014 T1 (UMAN) Industrial scale production of ammonia from nitrogen and hydrogen is carried out according to the reaction: N 2 + 3H 2 2NH 3 + Q 1) indicates the type of chemical reaction following criteria: a) thermal effect:... b) reversibility:... 2) Fill schemes formulas equations of chemical reactions with appropriate substances:
a) NH 3 + HOH... b) NH 3 + HCl... 3) Write a use of ammonia 7. 2014 PRE (REAL) Calcium chloride is used as an additive to accelerate the curing of the concrete, to increase its hardness and wear resistance. Write reaction equation to obtain calcium chloride, using the reactants as a: 1) a nonmetal..... 2) an oxide.... 3) a base..... 4) a salt..... 8. (REAL) Barium hydroxide is an alkali which is used to purify animal and vegetable fats. Write in the space provided after each reaction equation proposed schemes, choosing materials that will interact with barium hydroxide in string: FeO, СuCl 2, H 2 SO 4, CO 2 1) Ba(OH) 2 + acid... 2) Ba(OH) 2 + sare... 9. (REAL) Hydrochloric acid has many areas of application. Industrial scale production of hydrochloric acid is carried out according to the reaction: Cl 2 + H 2 = 2HCl + Q 1) indicates the type of chemical reaction following criteria: a) thermal effect... b) reversibility... 2) Fill diagrams illustrating chemical equations the chemical reactions of hydrochloric acid formulas and coefficients corresponding: а) MgO + HCl... b) Zn + HCl... 10. (REAL) Write an equation for each reaction of obtaining the proposed substances in accordance with the indicated type: a) combination reaction... CuO... b) decomposition reaction... CO 2... c) substitution reaction... H 2 O... d) double replacement reaction... Na 2 SO 4... 11. (REAL) In the chemistry class it is required to demonstrate some chemical properties of acids on the example of hydrochloric acid. Complete the table by choosing the needed substances for the following range: Cu(OH) 2, SO 3, H 2 O, Al 2 O 3, Cu, Mg, Ba(NO 3 ) 2. 12. (REAL) The aluminium chloride was included in the composition of the antiperspirants. This compound reduces the secretion of the sweat glands and narrows the pores. Write the equation reaction according to the indicated type, in which the aluminium chloride: a) is a reaction product: 1) combination reaction... 2) substituition reaction... 3) change reaction... b) is an initial substance:
1) change reaction... 13. (REAL) Oxide of sulfur (IV) is being used for the bleaching of straws, of silk and of wool, in other words of materials that cannot be bleached with chlorine. Below are the equations of reactions with the participation of the oxide of sulfur (IV): For each characteristic please choose a reaction and write its corresponding letter in the reserved space: 1) reaction of decomposition... 2) endothermic reaction... 3) irreversible reaction... 14. (REAL) The lime water (calcium hydroxide) shows chemical properties of the alkaline base. A). Please characterize the general chemical properties of alkaline bases, based on the example of the calcium hydroxide: fill the equations of reactions with the formulas of needed products and coefficients: 1) Ca(OH) 2 + HCl... +... 2) Ca(OH) 2 + Na 2 SO 4... +... 3) Ca(OH) 2 + СO 2... +... B). Indicate a field of use of the calcium hydroxide:... 15. (REAL) А. Fill in the blanks in the table: formula Systematic naming Technical name Area of use CaCO 3 Limestone Calcium hydroxide lime NaCl B. Pentru fiecare substanţă scrie cîte o ecuaţie de reacţie, ce caracterizează proprietăţile ei chimice, completînd schemele cu formule şi coeficienţi: 1. СаСО 3 +...... + СО 2 + Н 2 О 2.... + СО 2... + Н 2 О 3. NaCl +...... + AgCl 16. (REAL) Hydrogen is used for the production of ammonia, metals. А. Indicates the type of each reactions involving hydrogen as one of the criteria they meet: B. Write a reaction equation of the production of hydrogen according to the scheme: metal + acid C. It is well known that hydrogen gas is most easily. On the basis of this property proposes an example of the hydrogen: 17. 2015 BAZA (UMAN) Calcium hydroxide (slaked lime) is used for white washing rooms. Drying of white washed walls takes place according to the following reaction: Ca(OH) 2 + CO 2 СаСО 3 + H 2 O + Q 1. Circle the letters that correspond to the correct statements regarding to the
above reaction. This reaction is: a) irreversible; b) endothermic; c) synthesis; d) exothermic. 2. Complete the scheme of chemical reaction which illustrates the chemical property of calcium hydroxide with corresponding formulas and coefficients: Ca(OH) 2 + Na 2 SO 4 18. 2015 BAZA (UMAN) Sulfuric acid is widely used in manufacture of chemical products, in particular for the production of acids and inorganic salts. Write in the reserved space: A) the equation of the obtaining reaction of the sulfuric acid, according to the proposed scheme: acid oxide + water B) the equations of reactions of the sulfuric acid with two substances from the proposed line: CuO, BaCl 2, NaOH, Zn 1). 2) 19. 2015 BAZA (REAL) For each substance presented in column A choose a possible reagent from the column B and write the corresponding reactions equations. A B 1) chlorine a) potassium hydroxide 2) iron oxide (III) b) water 3) phosphorus oxide (V) c) aluminium 4) copper sulfate (II) d) nitric acid 1)... 2)... 3)... 4)... 20.2016 BAZA (REAL) There are given the reagents: aluminum, barium oxide, phosphoric acid, copper sulfate (II), carbon. Write an equation of obtaining reaction of the substances indicated below, with condition that in each case, one of reagents should be choosen from the proposed row. 1) a non-metal....... 2) an acid oxide.......... 3) a base........ 4) an acid........ 21. 2016 BAZA (UMAN) With magnesium sulphate solution - the paper and other materials are soaked to give them anti-incendiary properties. A. Complete the schemes of the chemical reactions, which illustrates the chemical properties of magnesium sulphate with corresponding formulas and coefficients: 1. MgSO 4 + NaOH.. 2. MgSO 4 + BaCl 2.. B. Write an equation of obtaining reaction of the magnesium sulphate, according to the proposed scheme: basic oxide + acid salt + water.... 5. Iron (II) chloride (ferrous chloride) is the basic component of preparation «Hemofer», that restores iron deficiency in the body and stimulates the synthesis of hemoglobin in the anemias, caused by iron deficiency.
22. 2016 BAZA (UMAN) Solve the problem. Calculate the weight of Iron (II) chloride, obtained by the interaction of iron (II) oxide with a mass of 144 g with hydrochloric acid, if the chemical reaction proceeds according to the following scheme: FeO + HCl FeCl 2 + H 2 O (establish and write the coefficients) It is given: Solution: Answer: 23. 2016 PRE (UMAN) Sodium carbonate is used to neutralize the acids in the waste water and removing water hardness. A. complete the reactions and write coefficients 1. Na 2 CO 3 + HNO 3 2. Na 2 CO 3 + CaCl 2 B. complete the reactions and write coefficients NaOH + CO 2 24. 2016 PRE (UMAN) The solution containing magnesium acetate is used in London as dust taking, reduces environmental pollution with 10 to 20%. Solve the problem. Calculate mass of magnesium acetate, obtained by magnesium interacting with acetic acid, if the result of the reaction liberates 4.48 L hydrogen gas (STP). The reaction takes place according to the equation CH 3 COOH + Mg (CH 3 COO) 2 Mg + H 2 (balance the equation) 25.2016 BAZA (REAL) 6. Reagents are proposed: hydrogen, aluminum hydroxide, zinc, sodium carbonate. Write each reaction equation for obtaining the substances listed below, provided that in each case one of reagents to be in the line proposed 1.a metal.. 2. a basic oxide 3. a base. 4. a salt..