Questions asked by Grace

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• Hello. Can someone help me with drawing hydrogen bonds among different molecules, with an example below? I understood how water molecules are linked to each other by hydrogen bonds. But I have a problem drawing these bonds in other biomolecules. Thanks!
  
• Hello. Can someone tell me why is DNA the genetic material in most of the organisms & not RNA? I need answers with reasoning & explanation. Thanks!
  
• I heard someone tell me a formula to convert molarity to molality: M= m(density of solution - 0.001 x M x Mb) where M-molarity, m-molality, Mb-molecular weight of solute. Could you please tell me if the formula is right, stating an example too? Thanks
  
• Could you help me with this? Justify the statement with an example: "Formality does not depend on what happens to a solute after it is dissolved in water, but depends on amount of solute dissolved in water."
  
• Why is it easy to work with normality than molarity? Can someone explain this question to me, preferably with an example?
  
• Is it true that for a value of #n# (n-principal quantum number), the value of #m_l# (#m_l#-magnetic quantum number) is equal to #n^2#? If it is true, can you please explain this to me? Thanks.
  
• Can anyone explain to me how is the molar concentration, or should I say the number of moles of water equal to 55.5? I need it with some explanation.
  
• Why do most of the plants grow on land and not in water? What are the reasons which makes land more favourable for growth of a plant as compared to water?
  
• Can you delete an answer?
  
• Can you help me with this? 20 g of glucose is dissolved in 150 g of water. Calculate the molarity, molality & mole fraction of glucose in solution.
  
• Can you help me with this? Commercially available HCl contains 38% w/w (weight by weight) of acid. If density is 1.19 g/ml, calculate molality, molarity and normality of the acid solution.
  
• Can someone help me in this? Concentrated #HNO_3# has specific gravity of 1.42. It contains 69% w/w (weight by weight) of #HNO_3#. Calculate the molarity and molality of the solution?
  
• How would you prepare a 0.2 M #NaOH# solution with a volume of 200 ml, from a 0.12 M #NaOH# solution with a volume of 200 ml?
  
• How do you prepare a 1 M #HCl# solution, which has a specific gravity of 1.18? The #HCl# solution has 35% purity. Calculate the volume required to prepare the solution.
  
• Numerical: How will you make a 0.35 M glucose solution? Also, prepare a 0.12 M solution of glucose from the above stock.
  
• Can you help me? From a 0.5 M #Na_2CO_3# solution having a volume of 300 ml, prepare a 0.075 M #Na_2CO_3# solution with a volume of 150 ml.
  
• Numerical: How will you prepare a 0.5 N #Na_2CO_3# solution having a volume of 150 ml?
  
• Numerical: How will you prepare a 0.75% #Na_2CO_3# solution?
  
• Can anyone solve this? From a 95% ethanol solution, prepare a 125 ml of a 75% ethanol solution.
  
• What do you mean by ion product? What is the definition for the ion product of water?
  
• How did the tap root system get its name? Why is it called "tap root"?
  
• What is a "crown root" in plants?
  
• An aqueous solution of #H_2SO_4# (molecular weight=98) contains 10.78 #g# of acid per #dm^3# of solution. Density of solution is 1.123 #g#/#ml#. What is the molarity, molality, normality and mole fraction of the solution?
  
• What do you mean by "Gene Overlap"? Do prokaryotes have gene overlapping?
  
• What do you mean by physiological buffers? What are the different types of buffers found in the blood? If possible, please state examples.
  
• How many grams of #NaCl# should be weighed to prepare 1 L of 20 ppm solution of #Na^+#?
  
• Can you solve this? The concentration of the #Zn^(2+)# ions in blood serum is 1.2 ppm. Express this amount in terms of millimole/L and milliequivalent/L.
  
• 3.6 #g# of oxalic acid (#H_2C_2O_4 * 2H_2O#) are dissolved and the volume is made upto 150 #ml#. Calculate the normality of the solution for redox titration?
  
• It is desired to prepare 4.0 M nitric acid from the available acid solution of strength 1.4 M & 6.8 M respectively. If the total volume of the 4.0 M nitric acid required to be prepared is 4 #dm^3#, calculate the volume of the 2 acid solutions to be mixed?
  
• A solution is prepared by dissolving 3.5 #g# of #KCl# in water & making the volume of solution to 250 #mL#. What is the millimoles of #KCl# dissolved?
  
• What is the difference between prokaryotic genes, eukaryotic genes and operon?
  
• The percentage purity of commercial #"HCl"# is 35% (w/w) & the specific gravity of the solution is 1.18 #"g"//"mL"#. What are the molarity, molality and normality?
  
• Calculate the mass of #KCl# that should be dissolved to form a 5 ppm #Cl^-# ion solution having a total volume of 20 #dm^3#?
  
• An aq soln of #NaH_2PO_4# is treated with a mixture of ammonium & magnesium ions to precipitate #Mg(NH_4)PO_4. 6H_2O# & is heated to #Mg_2P_2O_7# which is weighed. A soln of #NaH_2PO_4# gives 1.054 g of #Mg_2P_2O_7#. What's original weight of #NaH_2PO_4#?
  
• 1 g-atom of #Ca# was burnt in excess of oxygen & the oxide was dissolved in water to make up a one liter of solution. What is the normality of the alkaline solution?
  
• A sample of #KClO_3# on decomposition gives 448 #mL# of oxygen gas at NTP. Calculate: (a) Weight of oxygen produced (b) Weight of #KClO_3# originally taken (c) Weight of #KCl# produced?
  
• 10 #cm^3# of #H_2O_2# solution when reacted with #KI# solution produced 0.5 #g# of iodine. Calculate the percentage purity of #H_2O_2#?
  
• What is the principle of atom conservation? Explain with an example.
  
• 2.76 #g# of #K_2CO_3# was treated by a series of reagents so as to convert all of its carbon to #K_2Zn_3[Fe(CN)_6]_2#. Calculate the weight of the product?
  
• Calculate the volume of hydrogen required for complete hydrogenation of 0.25 #dm^3# of ethyne at STP?
  
• In the extraction of Fe(III) into diethyl ether, it is desired that the final acid concentration should be 1.0 M to 25 #mL# of the iron solution prepared in 1.0 M #HCl#. What volume of 12.0 M #HCl# should be added so that the final strength becomes 7.0 M?
  
• What is the "Carbonic acid-bicarbonate" buffer system?
  
• Why is van der Waals radius greater than covalent radius for covalent compounds?
  
• Why does electron affinity decrease with increase in size, and why does it increase with increase in nuclear charge?
  
• Why are carbohydrates called the "first energy source of the body", but not "main energy source of the body"?
  
• Why is plane polarised light not the same as monochromatic light?
  
• In carbohydrates, if there is more than 1 asymmetrical carbon atom, how do we determine the D and L-forms?
  
• What do you mean by an anomeric carbon? I want an answer preferably for anomeric carbon in carbohydrates (sugars)
  
• Can anyone explain to me how to identify epimers and anomers in carbohydrates (sugars)? Also, state examples.
  
• Can someone help me in identifying enantiomer pairs, specially in carbohydrates (sugars)? Also, state an example.
  
• How do you identify #alpha# and #beta# forms in sugars?
  
• If a bacteria has a diffusion barrier in its capsule, which prevents harmful substances from entering in it, then how do antibiotics affect bacteria?
  
• How do you get a slide of the stomata of the maize plant? Can someone tell me the procedure?
  
• If a bacteria has a diffusion barrier in its capsule, which prevents harmful substances from entering in it, then how do antibiotics affect bacteria?
  
• What is the regulatory gene, or the regulatory elements in an operon?
  
• What is the name of lactose and cellobiose? As in, like how we have #alpha#-D-glucopyranosyl_____ and so on for a disaccharide, I want to know the same for lactose.
  
• Which compound has a melting point of approx #134^@#C or #135^@#C? I don't know whether the melting points taken by me in the lab are correct. Is there any way to find if the M.P is correct?
  
• What is 'Pulvinus' in leaves? In which plants is it found? What are the functions?
  
• How many glucose residues are present in starch and glycogen?
  
• What is the "Particulate Hypothesis of Inheritance" and "Blending Hypothesis of Inheritance" in genetics?
  
• In which plants are "adventitious buds" found? Someone told me that adventitious buds are found in jackfruit. Is it true?
  
• Can you give me the structure for 2,3,5-trimethylhepta-2,4,6-triene?
  
• How do you determine the #alpha# and #omega# ends in fatty acids? How do we get the #alpha# and #omega# series? And are MUFA's non-essential fatty acids?
  
• What is the general formula for unsaturated fatty acids?
  
• In which plants are "adventitious buds" found? Someone told me that adventitious buds are found in jackfruit. Is it true?
  
• What is the "Particulate Hypothesis of Inheritance" and "Blending Hypothesis of Inheritance" in genetics?
  
• Derive the expression for second order reaction with unequal concentration for a reaction #A + B -># product when (1) if a > b & (2) if b > a, where "a mol/#dm^3#" and "b mol/#dm^3#" are the initial concentrations of A & B respectively?
  
• What is the structure for 3,4-dimethylpent-4-en-1-yne and 2,3-dimethylpent-1-en-4-yne?
  
• What is the reaction for the formation of a hemiketal carbon in fructose? Also, is this the same as mutarotation?
  
• What is the difference between stipules and bracts in leaves?
  
• Are MUFA (mono unsaturated fatty acids) non-essential fatty acids? If yes, then why?
  
• When 2 heterozygotes were crossed with each other i.e. #AaBb# x #AaBb#, the progeny showed: (i) A_B_ = 400 (ii) A_bb = 310 (iii) aaB_ = 290 (iv) aabb = 200 Does this prove Mendelian ratio? Find with a chi square test. (A and B- dominant)
  
• Justify the placement of the different amino acids in their respective classes. Also, what is special about each class of amino acids (eg. acidic, aromatic, etc.)?
  
• Why is the polarizability of an anion directly proportional to its size?
  
• How does the position of the axillary bud help in differentiating between a leaf and a branch? Also, how does the axillary bud position help to distinguish between a simple and compound leaf?
  
• Are MUFA (mono unsaturated fatty acids) non-essential fatty acids? If yes, then why?
  
• Justify: Sugars are connected by phosphodiester bonds?
  
• Why is mRNA the least stable?
  
• What is the phosphodiester bond and how is it drawn?
  
• What are the possible resonance structures of #CH_3-CH=CH-CH=O# and #CH_3-COO^-#? What is the order of stability of the contributing resonance structures?
  
• What is the #+M# and #-M# effect? What are examples of electron releasing and electron withdrawing groups?
  
• What do you mean by polar protic and polar aprotic solvents? What are some examples of these?
  
• What is the #E1# mechanism? Can you explain me the reaction for the dehydrohalogenation of tert-butyl chloride?
  
• What is the difference between a stamen and a male flower? What are some of the distinguishing characters?
  
• How is #NH_4SO_4# used in biochemical analysis?
  
• What is the derivation for the half life of a second order reaction with: (i) equal concentration of reactants for the reaction #2A -> "product"# (ii) unequal concentration of reactants for the reaction #A + B -> "product"#?
  
• What is the derivation for the half life of a second order reaction with: (i) equal concentration of reactants for the reaction 2A→product (ii) unequal concentration of reactants for the reaction A+B→product?
  
• State Berthelot's equation for real gases?
  
• What are the different parts in a centrifuge machine, and what are the different types of centrifuges?
  
• Related to the prebiotic synthesis, (a) What experiment did Stanley Miller perform in 1953? (b) What was his hypothesis? (c) What were his results? (d) In what way do these results contribute to our understanding of the origin of life?
  
• Scientists say that life arose on the primitive earth because of the conditions then existent on our planet. Explain this statement & comment whether life would have originated on our present day earth?
  
• The human chromosomes are divided into 7 groups and "s-e-x" chromosomes. What is the basis of this division? State the significance of karyotype analysis.
  
• Give chemical reactions to show the action of #CO_2# & ethanal on methyl magnesium bromide and methyl lithium?
  
• What is the effect of leaving group and solvent on the reaction rate of #S_N2# reaction?
  
• Draw the canonical forms for #CH_2=CH-CH=CH-CHO#, and compare their relative stabilities?
  
• Complete the equation & identify the type of reaction involved: #(CH_3) CH- Br# + aq. #KOH#?
  
• What do you mean by artificial and natural systems of classification? Can you also tell me the difference between the two? And, what is phylogenetic classification?
  
• What do you mean by artificial and natural systems of classification? Can you also tell me the difference between the two? And, what is phylogenetic classification?
  
• Which group is more oxidized, #-CHO# or #-CH_2OH#, and why?
  
• Explain why spontaneity depends on temperature?
  
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