पुढील उतारा वाचून त्यावर आधारित प्रश्नांची उत्तरे द्या :
रसायनशास्त्र : मोल संकल्पना व संहती
मोल हे असे एक रासायनिक प्रजातींचे SI एकक आहे की जे नेहमीच त्या रासायनिक प्रजातीच्या/पदार्थाच्या सूत्रांशी संबंधित असते आणि त्यात 6.022 × 1023, ॲव्होगॅड्रोच्या क्रमांकाइतके त्या पदार्थाच्या सूत्राचे कण असतात. ग्रॅमरेण्वीय वस्तुमान हे त्या रासायनिक पदार्थाचे ग्रॅममध्ये प्रदर्शित केलेले वस्तुमान असते आणि ते आपण त्या रासायनिक पदार्थाच्या सूत्रातील मुलद्रव्यांच्या अणुंच्या अणुभारांची बेरीज करून मिळवू शकतो. उदा. हायड्रोजन क्लोराइडचे ग्रॅमरेण्वीय वस्तुमान, 36.5 ग्रॅम हे आपण हायड्रोजनचे अणुवस्तुमान 1 आणि क्लोरिनचे अणुवस्तुमान 35.5 ग्रॅम यांची बेरीज करून मिळवता येते. वायुरूप पदार्थांचे ग्रॅमरेण्वीय घनफळ हे त्या वायुरूप पदार्थाच्या मोलचे, मानक दाब 1 atm = 101.325 kPa आणि तापमानात (273 K) मोजलेले घनफळ, हे 22.4 घन-डेसिमीटर इतके असते. हेच घनफळ आपण कोणत्याही इतर दाब आणि तापमानाच्या घनफळात सामान्य वायु समीकरण (P₁V₁)/T₁ = (P₂V₂)/T₂ वापरुन मिळवू शकतो.
रसायनज्ञ रासायनिक पदार्थांची संहति दोन प्रकारे : घनफळ (तापमानावर अवलंबून) आधारित : ग्रॅमरेणुता (M), प्रसामान्यता (N), सूत्रसंहति (F) आणि वस्तुमान (तापमानावर अवलंबून नाही) आधारित : मोललता (m), ग्रॅमरेणुअंश (χ) प्रदर्शित करतात. ग्रॅमरेणु संहति, M, ही एक घनडेसिमीटर द्रावणात त्या द्राव्याचे किती मोल आहेत ह्यावर ठरते. प्रसामान्यता, N, हे असे एक संहतिचे जास्त सोईस्कर एकक आहे की त्यात विश्लेषणीय सममुल्याची संख्या (माहित नसलेली) = मानक अभिक्रियाकारकाची संख्या (माहित असलेली) आणि ह्याचमुळे अनुमापनी विश्लेषणात अभिक्रिया समीकरणमितीची आवश्यकता नसते. प्रसामान्यता, N, ही एका घनडेसिमीटर द्रावणात त्या द्राव्याची किती सममुल्ये आहेत ह्यावर ठरते. एखाद्या रासायनिक अभिक्रियाकारकाची सममुल्य संख्या, ही त्या अभिक्रियाकारकाचे वस्तुमान आणि त्याचाच सममुल्यभार यांचे गुणोत्तर असते. अशी आहे द्राव्याच्या सममुल्यभाराची व्याख्या. "त्या द्राव्याचे असे वस्तुमान की ज्यात 1 भाग हायड्रोजन आहे, जे 1 भाग हायड्रोजनशी अभिक्रिया करते किंवा 1 भाग हायड्रोजन विस्थापित करते".
बाजारात संहत अभिकारके उदा : आम्ल, अल्क उपलब्ध असतात. रोजच्या प्रयोगांकरिता, प्रयोगशाळेमध्ये यांचं संहत अभिकारकांचे विरल द्रावण योग्य प्रमाणात पाणी मिसळुन करणे गरजेचे असते. हे विरलन, संहत द्रावणातील मोलसंख्या किंवा सममुल्य संख्या ही विरल द्रावणातील मोलसंख्या किंवा सममुल्य संख्ये इतकीच असली पाहिजे ह्या महत्वाच्या पायावर अवलंबून असते.
वस्तुमानावर अवलंबून असलेली; मोललता (m) म्हणजेच एका किलोग्रॅम द्रावकामध्ये विरघळवलेल्या द्राव्याची मोलसंख्या आणि ग्रॅमरेणुअंश, (χ) हा एका द्राव्याच्या द्रावणामध्ये त्याच द्राव्याचा ग्रॅमरेणुअंश ही दोन एकके आहेत.
(अणु वस्तुमान : H = 1, He = 4, Ne = 20, N = 14, O = 16, S = 32, Cl = 35.5, Ar = 40, Ag = 108).
समुद्रपातळीवर असलेल्या प्रयोगशाळेत वापरण्यासाठी, वर्षाच्या कोणत्याही दिवशी खालीलपैकी कोणते संहतीचे एकक सर्वात अचूक राहील?
EN
Read the following passage and answer the questions:
Chemistry: Mole Concept and Solutions The mol is a SI unit of the amount of a chemical species/substance. It is always associated with the formula and contains 6.022 × 1023 Avogadro's number of particles of the species represented by that formula. The molar mass of any chemical substance is the mass in gram of one mol of that substance, this can be obtained by adding the atomic weights of the component elements present in the formula of the substance (eg. molar mass of HCl is obtained by adding atomic weight of H ie 1 and Cl ie 35.5 = 36.5 g). The molar volume, ie 22.4 dm3 is the volume of one mol of any gas (assumed to behave ideally) at 273 K and 1 atm = 101.325 kPa pressure (STP). This volume can be converted to the volume under any condition of temperature and pressure by using general gas equation (P₁V₁)/T₁ = (P₂V₂)/T₂. Chemists express the concentration of chemical species on the basis of volume (temperature dependent) ie molarity (M), normality (N), formality (F) etc. as well as mass (temperature independent) ie molality (m), mole fraction (χ) etc. The molar concentration, M, of a solution of any chemical species is the number of mol of that species present per dm3 of the solution. Normality, N, is a more convenient unit of concentration as the number of equivalents of an analyte (unknown concentration) present = the number of equivalents of the standard reagent (known concentration) added. As a consequence, the stoichiometry of the reaction need not be derived every time a titrimetric analysis is performed. Normality is the number of equivalents of the solute present per dm3 of the solution. The number of equivalents is the ratio of weight in gram of the solute to the equivalent weight of that solute. The equivalent weight of the solute then needs to be known which is defined as "the weight which contains, combines with or displaces one part by weight of hydrogen". Commercially available reagents ie acids and bases are highly concentrated. To use them in laboratory for routine experiments, one needs to dilute the solutions with definite quantity of water. The total number of equivalents or mol in both, concentrated and dilute solution, must be the same is the basis of this dilution. The mass based concentration units are molality, m, ie the number of mol of solute dissolved in a kg of solvent and mole fraction, χ, ie the fraction of the total number of mol of that component present in the given solution. Atomic weights : H = 1, He = 4, Ne = 20, N = 14, O = 16, S = 32, Cl = 35.5, Ar = 40, Ag = 108 On any day of the year, to use in laboratories at sea level the most correct concentration unit is:
Chemistry: Mole Concept and Solutions The mol is a SI unit of the amount of a chemical species/substance. It is always associated with the formula and contains 6.022 × 1023 Avogadro's number of particles of the species represented by that formula. The molar mass of any chemical substance is the mass in gram of one mol of that substance, this can be obtained by adding the atomic weights of the component elements present in the formula of the substance (eg. molar mass of HCl is obtained by adding atomic weight of H ie 1 and Cl ie 35.5 = 36.5 g). The molar volume, ie 22.4 dm3 is the volume of one mol of any gas (assumed to behave ideally) at 273 K and 1 atm = 101.325 kPa pressure (STP). This volume can be converted to the volume under any condition of temperature and pressure by using general gas equation (P₁V₁)/T₁ = (P₂V₂)/T₂. Chemists express the concentration of chemical species on the basis of volume (temperature dependent) ie molarity (M), normality (N), formality (F) etc. as well as mass (temperature independent) ie molality (m), mole fraction (χ) etc. The molar concentration, M, of a solution of any chemical species is the number of mol of that species present per dm3 of the solution. Normality, N, is a more convenient unit of concentration as the number of equivalents of an analyte (unknown concentration) present = the number of equivalents of the standard reagent (known concentration) added. As a consequence, the stoichiometry of the reaction need not be derived every time a titrimetric analysis is performed. Normality is the number of equivalents of the solute present per dm3 of the solution. The number of equivalents is the ratio of weight in gram of the solute to the equivalent weight of that solute. The equivalent weight of the solute then needs to be known which is defined as "the weight which contains, combines with or displaces one part by weight of hydrogen". Commercially available reagents ie acids and bases are highly concentrated. To use them in laboratory for routine experiments, one needs to dilute the solutions with definite quantity of water. The total number of equivalents or mol in both, concentrated and dilute solution, must be the same is the basis of this dilution. The mass based concentration units are molality, m, ie the number of mol of solute dissolved in a kg of solvent and mole fraction, χ, ie the fraction of the total number of mol of that component present in the given solution. Atomic weights : H = 1, He = 4, Ne = 20, N = 14, O = 16, S = 32, Cl = 35.5, Ar = 40, Ag = 108 On any day of the year, to use in laboratories at sea level the most correct concentration unit is: