Nokea
What is the net ionic equation for the reaction: 2HCl(aq) + Ba(OH)2(aq) → 2H2O(l) + BaCl2(aq)?
- A. 2H+(aq) + 2OH-(aq) → 2H2O(l)
- B. 2HCl(aq) + Ba(OH)2(aq) → BaCl2(aq) + 2H2O(l)
- C. 2H+(aq) + Ba2+(aq) → Ba2+(aq) + 2H+(aq)
- D. Ba(OH)2(aq) + HCl(aq) → BaCl2(aq) + 2H2O(l)
Correct Answer: A
Rationale: In the given reaction, the complete ionic equation is: 2H+(aq) + 2Cl-(aq) + Ba2+(aq) + 2OH-(aq) → 2H2O(l) + Ba2+(aq) + 2Cl-(aq). Spectator ions (Ba2+ and Cl-) do not participate in the net ionic equation, which simplifies to: 2H+(aq) + 2OH-(aq) → 2H2O(l). This equation represents the significant species involved in the reaction, showcasing the formation of water from the combination of hydrogen ions and hydroxide ions, resulting in the production of water molecules.
You may also like to solve these questions
Which of the following is NOT a factor affecting the rate of a chemical reaction?
- A. Concentration of reactants
- B. Temperature
- C. Presence of a catalyst
- D. Color of the reaction mixture
Correct Answer: D
Rationale: The color of the reaction mixture is not a factor affecting the rate of a chemical reaction. Factors such as the concentration of reactants, temperature, and the presence of a catalyst can influence the rate of a chemical reaction by affecting the frequency of collisions between reactant molecules and the energy of those collisions. The color of the reaction mixture is a physical property and does not directly impact the kinetics or speed of the reaction process. It is a qualitative observation that does not alter the reaction rate or mechanisms involved.
Which property of a substance refers to the force exerted on an object due to gravity?
- A. Mass
- B. Weight
- C. Density
- D. Volume
Correct Answer: B
Rationale: The correct answer is 'Weight.' Weight is the force exerted on an object due to gravity. Mass, on the other hand, refers to the amount of matter in an object. Density is the mass per unit volume of a substance, and volume is the amount of space occupied by an object. In this context, weight specifically relates to the gravitational force acting on an object, making it the most appropriate choice among the options provided.
What is the primary function of the large intestine?
- A. Digesting and absorbing nutrients
- B. Storing and mixing food
- C. Breaking down carbohydrates
- D. Absorbing water and electrolytes
Correct Answer: D
Rationale: The primary function of the large intestine is to absorb water and electrolytes from the indigestible food matter that passes through it. This absorption process aids in the formation of solid waste (feces) before it is excreted from the body. Choices A, B, and C are incorrect because the large intestine does not primarily digest and absorb nutrients, store and mix food, or break down carbohydrates. These functions are primarily carried out by the small intestine.
What is the process by which lighter nuclei fuse to form heavier nuclei, releasing a large amount of energy?
- A. Fission
- B. Fusion
- C. Radioactivity
- D. Chain reaction
Correct Answer: B
Rationale: Fusion is the process by which lighter nuclei combine to form heavier nuclei, releasing a large amount of energy in the process. This process is the source of energy in stars, including our Sun. Fission, the process of splitting heavier nuclei into lighter nuclei, is not correct. Radioactivity involves the emission of particles or radiation from the nucleus of an unstable atom, which is different from fusion. A chain reaction is a self-sustaining reaction where the products of one reaction cause further reactions, which is unrelated to fusion.
Which division of the autonomic nervous system is responsible for the 'rest and digest' response, promoting relaxation and conservation of energy?
- A. Sympathetic nervous system
- B. Parasympathetic nervous system
- C. Somatic nervous system
- D. Central nervous system
Correct Answer: B
Rationale: The correct answer is B: Parasympathetic nervous system. The parasympathetic nervous system is responsible for the 'rest and digest' response, promoting relaxation, conserving energy, and facilitating activities like digestion and lowering heart rate. The sympathetic nervous system, which is not the correct answer, triggers the 'fight or flight' response, preparing the body for stressful situations by increasing heart rate, dilating airways, and releasing adrenaline. The somatic nervous system (choice C) controls voluntary movements, not the autonomic functions related to 'rest and digest.' The central nervous system (choice D) includes the brain and spinal cord and is not specifically involved in the autonomic regulation of bodily functions like the 'rest and digest' response.