Chemistry test

Collection of assignments by discipline
"Chemistry" Part 3


Task 1
Choose the correct answer to the question and mark it in the answer card after studying the manual.
Question 1. What is called recovery?
1. the reaction of interaction of hydrogen with some element;
2. the process of giving up electrons by an element;
3. the process of accepting electrons by an element;
4. the process of accepting and giving up electrons;
5. the process of neutralizing alkali with any acid.
Question 2. Which of the following reactions is redox?
1.Cr2S2 + H2O  3 H2S +2 Cr (OH) 3;
2. Na2S + Br2  S + 2 NaBr;
3. 4 KCN +2 Fe (CN) 2  K4 [Fe (CN) 6];
4. CaCO3 = CaO + CO2;
5. HCl + KOH = KCl + H2O.
Question 3. Which of the following compounds is formed as a reduction product during the interaction of KMnO4 with a solution of sodium sulfite in a neutral medium?
1. MnO2;
2. K2MnO4;
3. MnSO4;
4. H2MnO4;
5. MnO3.
Question 4. Make a reaction equation involving: a) hydrogen peroxide and potassium iodide; b) hydrogen peroxide and silver oxide, if iodine is released in the first case, and silver and oxygen in the second.
What properties does hydrogen peroxide exhibit in this case?
1. oxidizing agent, reducing agent;
2. reducing agent, oxidizing agent;
3. in both cases, an oxidizing agent;
4. in both cases, a reducing agent;
5. Hydrogen peroxide does not exhibit redox properties.
Question 5. Which of the following processes is restorative?
1. As -3  As + 3;
2. Sn + 4  Sn + 2;
3. Cr + 3  Cr + 6;
4. S + 4  S + 6;
5.N + 3  N + 5.
Task 2
Choose the correct answer to the question and mark it in the answer card after studying the manual.
Question 1. In which of these reactions is sulfur oxidized?
1. S + Zn  ZnS;
2. S + O2  SO2;
3S + C  CS2;
4. H2 + S = H2S;
5. Fe + S = FeS.
Question 2. When ammonia reacts with heated copper oxide, copper, nitrogen and water are formed. What is restored in this case?
1. copper ions;
2. nitrogen ions;
3. hydrogen ions;
4. oxygen ions;
5. ions of copper and oxygen.
Question 3. What chemical processes occur when hydrogen sulfide interacts: a) with an aqueous solution of lead nitrate and b) iodine?
1. both reactions are redox;
2. in the first case, an exchange reaction takes place, in the second - a redox process;
3. in the first case, a redox process takes place, in the second - an exchange reaction;
4. in both cases, exchange reactions occur;
5. in the first case, the process of salt hydrolysis occurs.

Question 4. Atoms or other forms of which elements are only reducing agents?
1. anions: I-, Cl-, Se-2, P -3; b) atoms of some elements in a high oxidation state: Mn + 7, V + 5, Se + 6, P + 5;
2. atoms of some elements in an intermediate oxidation state: Mn + 4, Cl + 5, Se + 4, P + 3;
3. free halogens;
4. iron cations (III);
5. There is no right answer.
Question 5. Which of these types of reactions is redox?
1.the decomposition reaction: CaCO3  CaO + CO2;
2. substitution reaction: Zn + СuSO4  ZnSO4 + Сu;
3. double exchange reaction: Na2S + ZnСl2  ZnS +2 NaСl;
4. neutralization reaction: НСl + NaOH = NaCl + H2 O;
5. reaction of complex formation: 4 KCN + Fe (CN) 2 = K4 [Fe (CN) 6].
Task 3
Choose the correct answer to the question and mark it in the answer card after studying the manual.
Question 1. Find the correct option in the electronic circuits of the reaction of zinc interaction with nitric acid in the presence of sodium hydroxide, if this produces ammonia, sodium zincate and water.
1. Zn0 - 2e = Zn + 2; N + 5 + e = N + 4;
2. Zn0 - 2e = Zn2 +; N + 5 + 4e = N + 1;
3. Zn0 - 2e = Zn + 2; N + 5 + 3e = N + 2;
4. Zn0 - 2 e = Zn2 +; 2 N + 5 + 10 e = N2 0;
5. Zn0 - 2 e = Zn2 +; N + 5 + 8 e = N -3.