Question: (a) The reaction between hydrogen, H 2 (g), and nitrogen monoxide, NO(g), has the following rate equation, rate = k[H 2 (g)][NO(g)] 2 , The overall equation for the reaction is, 2H 2 (g) + 2NO(g) → N 2 (g) + 2H 2 O(l), and the reaction takes place by a two step mechanism. (i) What is the meaning of reaction mechanism? (ii) Explain what a rate determining step is. (iii) Giving your reasoning, write two equations that could describe the two mechanistic steps for the above reaction. It is important to identify the rate determining step. Answers: (i) A reaction mechanism is the step by step sequence of elementary reactions through which the overall chemical reaction occurs. (ii) A rate determining step is the slowest step of complex reaction, and this step determines the overall reaction rate. (iii) Based on the rate equation we can conclude that rate determining step is H 2 (g) + 2NO(g)
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Question: WHAT IS DIFERENCE BETWEEN SALINITY AND TDS(TOTAL DISSOLVE SOILD THAT DISPLAY ON CONDUCOTMETER)? Answer Total dissolved solid (TDS) is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular (colloidal sol) suspended form. Salinity is the saltiness or dissolved salt content of water. So, salinity is part of total dissolved solids Total dissolved solids are normally discussed only for freshwater systems, as salinity includes some of the ions constituting the definition of TDS. A quick way of salinity measuring is to use a conductivity meter and read off the electrical conductivity. The idea being that a salty solution, because it is full of charged particles will conduct electricity. Most conductivity meters give readings in micro Siemens per cm (µS/cm). Now some salinity meters read off parts per million (ppm). This is an approximation - the problem is that ppm is a measure o
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Question: 600 ml of ozonised oxygen at STP was found to weight one gram. What is the volume of O3 in the ozonoised oxygen ? (1) 200 ml (2) 150 ml (3) 100 ml (4) 50 ml Answer: From the ideal gas law we can find the expression for the molar mass: pV = nRT n = m/M pV = mRT/M M = mRT/pV = 1∙8.314∙273/(100000∙0.0006) = 37.8 g/mol M(O 3 ) = 48 M(O 2 ) = 32 The average molar mass of gas can be expressed as the sum of molar masses multiplied by mole fraction. Let x denote the mole fraction of ozone, so the mole fraction oxygen is 1-x. Now we can write the expression for x: 48x + 32(1-x) = 37.8 x = 0.3625 The volume of ozone is the total volume multiplied by the ozone mole fraction: V(O 3 ) = x∙V = 217.5 ml ≈ 200 ml So, the correct option is (1). Get your answer at https://www.chemtutor.me/ See more solved problems at https://www.chemtutor.me/problems/ Also check out our free chemistry tools at https:/
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Question If a reaction has large value of K C , will it go to completion and why? Answer Let us consider a chemical reaction in general form: aA + bB → cC + dD, where A and B are reactants, C and D are products and a, b, c and d are stoichiometric coefficients. An equilibrium reaction proceeds until reaching equilibrium. And the value of K C characterizes this equilibrium. Since the products are in the numerator of K C expression, the greater the K C the greater the concentration of products at the equilibrium, and vice versa: the small value of K C indicates great amount of reactants and small amount of products at the equilibrium. So, if a reaction has large value of K C , amount of products considerably exceeds the amount of reactants, and this means the reaction reaches close to completion. Get your answer at https://www.chemtutor.me/ See more solved problems at https://www.chemtutor.me/problems/ Also check out our free chemistry tools at https://
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Question Which has no conformational isomers? (1) CH 3 OH (2) CH 3 CHO (3) CH 2 = CH–Cl (4) CH 3 –NH 2 Answer Conformational isomerism is a form of stereoisomerism in which the isomers can be interconverted exclusively by rotations about formally single bonds. Such isomers are generally referred to as conformational isomers or rotamers. Rotation is possible around single bonds only and not possible around double bonds. So, the correct answer is (3) CH 2 = CH–Cl has no conformational isomers. All other listed substances have single bonds (C – O (1) and C – C (2 and 4)), rotation around which give rise conformational isomerism. Rotation around C = C bond of CH 2 = CH–Cl is not possible, that is why it has no conformational isomers. Get your answer at https://www.chemtutor.me/ See more solved problems at https://www.chemtutor.me/problems/ Also check out our free chemistry tools at https://www.chemtutor.me/tools/
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Question: How much KClO 3 must be heated to obtain 2.50 gram of oxygen? Answer: The equation of this reaction: 2KCIO 3 → 2KCI + 3O 2 For solving this question we can use proportion: Molecular mass of KCIO 3 = 122.5*2 = 245 Molecular mass of O 2 = 32*3 = 96. Suppose that x is mass of KCIO 3 . So, we get the proportion: x/245 = 2.50g/96 x = 6.38g of KCIO 3 Get your answer at https://www.chemtutor.me/ See more solved problems at https://www.chemtutor.me/problems/ Also check out our free chemistry tools at https://www.chemtutor.me/tools/
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Question Thiocyanate (SCN-) has the potential to coordinate metals either via N-atom or S-atom linkage. Predict the coordination linkage (N-atom or S-atom) and geometry for Zn (II) and Cu (I). Answer The general rule based on the experimental evidence states that class A metals (forming hard acids) tend to form N-bonded thiocyanate complexes, whereas class B metals (forming soft acids) tend to form S-bonded thiocyanate complexes. This classification is based on the HSAB (hard and soft (Lewis) acids and bases) concept, which is also known as the Pearson acid base concept. According to it: Type of Acid CHARACTERISTICS EXAMPLES Hard acids * Atomic centres of small ionic radii (<90 pm). * High positive charge. * Empty orbitals in their valence shells. * Low electronegativity (0.7-1.6) and low electron affinity. * Likely to be str