Bond energy is defined as the amount of energy required to break a bond. These values are positive, indicating that bond breaking is endothermic.
For a certain first-order reaction, it is found that it takes 156 seconds for the concentration of reactant to fall from 0.100M to 0.0500M. How much time would it take for the concentration of reactant to fall from 0.0500M to 0.0250M? a. 165 seconds b. 76 seconds c. 156 seconds d. 98 seconds
1. What is the value of the standard enthalpy of formation for any element under standard conditions? A. 273 J/mol B. 0.24 J/mol C. 4.18 J/mol D. 0 J/mol 2. Which of the following represents an increase in entropy? A. freezing of water B. boiling of water C. crystallization of salt from a supersaturated solution D. the reaction 2 NO(g) ! N2O2(g)
Chemical Reactions on the Basis of Rate of Reaction Rate of Reaction Factors Affecting Rate of Reaction Rate Law Expressions Characteristics of rate constant Integrated Rate Equation for Zero Order Reactions Integrated Rate Equation for First Order Reactions Pseudo First Order Reaction Methods to Determine Order of Reaction Graphical method Arrhenius Equation Activated complex (or transition state) Theory of Reaction Rates The Activated Complex Theory or Transition State Theory Photochemical ...
ATOMS, MOLECULES AND NUCLEI ( Answers at the end of all questions )
Question: Almost the entire mass of an atom is concentrated in the__________. a) proton b) electrons c) nucleus d) neutrons Question: Electron was discovered by___________. a) Chadwick b) Thomson c) Goldstein d) Bohr Question: An atom has a mass number of 23 and atomic number 11. The number of protons are_________. a) 11 b) 12 c) 23 d) 44
Question: Which of these pairs of metal has variable valencies? weight : 2 answer : Iron and copper Zinc and caesium Iron and strontium Barium and scandium question: J.J. Thomson’s model of the atom fell into disrepute and was replaced by one of the following weight : 2 option : Dalton’s theory answer : Rutherford Nuclear model option : Bohr model option : Balmer series model
Oxidation-reduction (redox) reactions Rules for Assigning Oxidation Numbers Identifying Redox Reactions Balancing Redox Reactions
1.The elements characterized as nonmetals are located in the periodic table at the (1) far left; (2) bottom; (3) center; (4) *topright. 2. An element that is a liquid at STP is in Group (1) IA; (2) IIA; (3) IB; (4) *IIB. 3. Elements that have properties of both metals and nonmetals are called (1)*metalloids; (2) halogens; (3) alkali metals; (4) transition elements. 4. Which of the following noble gases has the lowest normal boiling point? (1) *Ne; (2) Ar; (3) Kr; (4) Xe.
For a certain first order reaction, it is found that it takes 156 seconds for the concentration of reactant to fall from 0.100 M to 0.0500 M. How much time would it take for the concentration of reactant to fall from 0.0500 M to 0.0250 M? a. 165 seconds b. 76 seconds c. 156 seconds d. 98 seconds A catalyst functions by: a lowering the energy of the reactants. b. lowering the energy of the products. c. decreasing the rate of the reverse reaction. d. providing a reaction path with a lower acti...
Electrochemistry Questions
1. A gas occupy 1.12dm3 at stp. If the mass of the gas is 2.3g. What is the gas A. Sulphur(vi) oxide B. Nitrogen(iv)oxide C. Sulphur(iv)oxide D. Carbon(iv) oxide 2. Which of these is liquid at room temperature A. F B. Cl C. Br D. I 3. 50X is in the same group as A. 6C B. 11Na C. 17Cl D. 13Al 4. What is the formula for aluminum trioxosulphate (iv) A. Al2(SO3)2 B. AlSO4 C. Al2(SO3)3 D. Al2(SO4)3
ELECTROCHEMISTRY ELECTROCHEMICAL CELLS OR GALVANIC CELLS / VOLTAIC CELLS ELECTROCHEMICAL CONVENTIONS TYPES OF ELECTROCHEMICAL CELLS Relation between electrical energy and free energy REVERSIBLE AND IRREVERSIBLE CELLS STANDARD ELECTRODE POTENTIAL THE NERNST EQUATION FARADAY’S LAWS OF ELECTROLYSIS Faraday’s second Law of Electrolysis
1. A certain rate law is given as Rate = k[H2][Br2]1/2. What is the reaction order? a. ½ b.3/2c. ¾ d. 1/3 2. Using the integrated form of the rate law, determine the rate constant k of a zero-order reaction if the initial concentration of substance A is 1.5 M and after 120 seconds the concentration of substance A is 0.75 M. a. 0.00625 M/s b. 0.00875 M/s c. 0.00986 M/s d. 0.0096 M/s 3. Determine the half-life of zero-order reaction if the original concentration of the reactant is 1.2 M ...
1. Which of the following statements is true about ORDER of a reaction? a. It is obtained from a single balanced equation b. It is always a whole number c. It cannot be obtained from a balanced chemical equation d. It reveals some basic facts about reaction mechanism Answer = c 2. One of the following statements is not true about the MOLECULARITY of a reaction a. It is always a whole number b. It is generally not exceeding three and never zero. c. It reveals some basic facts about react...