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Question: Which of the following is FALSE about the solutions?

4. The rule "like dissolves like" means that if the solvent and solute are both in the same phase (i.e., both liquids), they will dissolve most readily.

1. Solution is made when a solvent dissolves in a solute.

2. Regardless of the solute, the solvent must always be a liquid. (correct)

3. Real solution is always a homogeneous mixture.

5. Substances with a similar molecular weight to the solvent will dissolve most readily. (correct)

Question: How many grams of salt (NaCl) has to be dissolved in 50 g of water in order to make a solution of 0.5 M? M(NaCl) = 58.44 g/mol

• 1.504 g

• 2.920 g

• 1.631 g

• 1.550 g

• 1.461 g (correct)

Question: When a solute is dissolved in a solvent:

• Freezing point of the solution increases.

• Concentration of solvent increases.

• The vapor pressure of the solution increases.

• Osmotic pressure of the solution decreases.

• The boiling point of the solution increases (correct)

Question: Which observation(s) reflect(s) colligative properties? (A) A 0.5 M NaBr solution has a higher vapor pressure than a 0.5 M BaCl₂ solution. (B) A 0.5 M NaOH solution freezes at a lower temperature than pure water. (C) Pure water freezes at a higher temperature than pure methanol.

• B and C Signup and view all the answers

Question: Based on the equilibrium constants given, in which of these reactions are the products most favored over the reactants?

• Keq = 3.5 Signup and view all the answers

Question: What is the [H_3O^+] in a solution with [OH^-]of 5.67×10−3 mol/L5.67 \times 10^{-3} , \text{mol/L}5.67×10−3mol/L?

• 1.76×10−12 mol/L Signup and view all the answers

The pH of a buffer solution, prepared by combining 50.0 mL of 1.00 M potassium benzoate and 50.0 mL of 1.00 M benzoic acid, is 4.2. After the addition of 7.0 mL of 0.5 M HCl acid, the pH of the buffer will change to 3.76. The KaK_aKa of benzoic acid is 6.30×10−56.30 \times 10^{-5}6.30×10−5.

4.14 Signup and view all the answers

Question: Consider a solution initially containing 0.40 mol fluoride anion (F⁻) and 0.30 mol of hydrogen fluoride (HF). If 0.40 mol of HCl are added to this solution, which of the following statements is/are FALSE?

• Addition of 0.40 mol of HCl will lower the pH of solution by 0.4 unit. Signup and view all the answers

Question: Zinc sulfide is converted into zinc oxide by heating in a furnace: ZnS(s)+1.5O2(g)→ZnO(s)+SO2(g)\text{ZnS(s)} + 1.5\text{O}_2\text{(g)} \rightarrow \text{ZnO(s)} + \text{SO}_2\text{(g)}ZnS(s)+1.5O2(g)→ZnO(s)+SO2(g) What is the standard enthalpy change (ΔH∘\Delta H^\circΔH∘), in kJ/mol, for the reaction? Given Data: ΔHf∘ (kJ/mol) of substances:\Delta H_f^\circ , (\text{kJ/mol}) , \text{of substances:}ΔHf∘(kJ/mol)of substances: • ZnS(s): -206 • O2(g)O_2(g)O2(g): 0 • ZnO(s): -350 • SO2(g)SO_2(g)SO2(g): -297

• -441 Signup and view all the answers

Question: Which equation demonstrates that enthalpy is the total energy of a system?

<ol> <li>ΔH = ΔU - pΔV</li> </ol> Signup and view all the answers

Question: The formulation of Hess’s law is:

• Total change of enthalpy in a chemical reaction is independent of the route by which the chemical reaction takes place as long as the initial and final conditions are the same. Signup and view all the answers

Question: Gibbs free energy expresses:

• Amount of energy capable of doing work during the reaction at constant temperature and pressure. Signup and view all the answers

Which of the given reactions is considered a unimolecular reaction?

<ol start="3"> <li>NH₄NO₃ (solid) → (heating) → N₂O (gas) + H₂O (gas)</li> </ol> Signup and view all the answers

Select the correct expression of a rate law for the following chemical reaction: 2 NO+H2→N2O+H2O2 , \text{NO} + \text{H}_2 \rightarrow \text{N}_2\text{O} + \text{H}_2\text{O}2NO+H2→N2O+H2O

v=k[NO]2[H2] Signup and view all the answers

Question: Which of the following statements correctly describe the effect of temperature on chemical reaction rate?

• Increasing in temperature by 10∘C10^\circ \text{C}10∘C results in 2-4 folds increasing of the rate of chemical reaction. Signup and view all the answers

Question: A 10∘C10^\circ \text{C}10∘C increase in temperature triples the rate of a chemical reaction. How many times does the rate of the chemical reaction increase when the temperature rises from 10∘C10^\circ \text{C}10∘C to 40∘C40^\circ \text{C}40∘C?

27 Signup and view all the answers

question: Which of the following statements about catalysts is/are correct?

• Increase reaction rate by lowering the energy of activation. Signup and view all the answers

QUESTION Fill in the blanks: The complex compounds can be classified as:

Ag(NH₃)₂Cl:- Amine coordination compound. Signup and view all the answers

Question: What is the use of EDTA in medicine?

• In "chelation therapy" in the case of poisoning with mercury and lead. Signup and view all the answers

Question: Which of these compounds are complexones?

<ol> <li>Na₂[H₂EDTA]</li> </ol> Signup and view all the answers

Question: Which of the following statements about coordination compounds are CORRECT?

• The complex compound is electrically neutral. Signup and view all the answers

Question: There is a coordination compound [Cr(H₂O)₄Cl₂]Cl. Which particle of this molecule is called an inner sphere?

<ol start="4"> <li>[Cr(H₂O)₄Cl₂]⁺</li> </ol> Signup and view all the answers

Question: Which of these substances is the least soluble? Answer considering solubility product constant (Ksp).

<ol start="5"> <li>AgI Ksp = 1.5 × 10⁻¹⁶</li> </ol> Signup and view all the answers

Question: Which of the following statements about colloids is true?

• Colloidal solutions are heterogeneous dispersal systems. Signup and view all the answers

Question: Considering Hardy-Schulze law, choose the electrolyte which is the weakest in the coagulation of the colloid given below (you should add the highest amount of this electrolyte to induce coagulation). {m[Fe(OH)₃]·nFe³⁺ (3(n-x)Cl⁻)³ₓ⁺·3ₓCl⁻}

• MgSO₄ Signup and view all the answers

Question: In the colloidal solution, the structure of the micelle is presented in the scheme: {m[AgCl]nCl(n−x)K}x+xK+{m[AgCl]nCl(n-x)K}^x+ xK^+ What is the charge of the granule in the micelle?

• Positive because of (n−x)K+ Signup and view all the answers

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