FREE Trial S
study help categories /Sciences

Top Selling Sciences Questions

The intermediate cation A in the sequence C 6 H 6 + E + A C 6 H 5 E + H + is best shown as H H E H E () (b) () (d) `E For each of the three crossed aldol reactions described in Problem 47, indicate which, if any, of the multiple possible products should predominate in the reaction mixture and explain why. Data From... Name each of the following compounds according to IUPAC or Chemical Abstracts. Pay attention to the order of precedence of the functional groups. a. b. c. d. CI Attempted CrO 3 oxidation of 1,4-butanediol to butanedioic acid results in signifi cant yields of g-butyrolactone. Explain mechanistically. :0 y-Butyrolactone Fill in suitable reagents to carry out the following transformations. (a) (CH 3 ) 2 CHCH 2 CHO (CH 3 ) 2 CHCH 2 CO 2 H (b) (c) (d) (e) (f) (CH 3 ) 3 CCO 2 H (CH 3 ) 3 CCO 2 CH(CH 3 ) 2 (g) - ... Give the product of each of the following reactions. (a) (b) (c) (d) (e) CH 1. , . 2. H', . CH The viewing window in a diving suit has an area of roughly 65 cm 2 . (a) If an attempt were made to maintain the pressure on the inside of the suit at 1 atm, what force (N and lb f ) would the window... There are two stable isotopes of nitrogen, 14 N and 15 N. How many protons and neutrons does each isotope have? Spray drying is a process in which a liquid containing dissolved or suspended solids is injected into a chamber through a spray nozzle or centrifugal disk atomizer. The resulting mist is contacted... Describe with equations how you might separate a mixture of aniline, p-cresol, benzoic acid, and toluene using ordinary laboratory reagents. An aqueous solution containing 35 wt% MgSO 4 is fed to an evaporative crystallizer operating at 50F. The vapor generated is 20% by mass of the feed. The solution, which contains 23 wt% MgSO 4 , and... Suggest practical methods by which the rate of reaction can be investigated in each of the following cases: a. Magnesium reacting with hydrochloric acid b. Nitrogen monoxide reacting with oxygen. a. Oxygen has an atomic number of 8 and mass number 16. What is the electron structure of the oxygen atom? b. How many electrons, neutrons and protons are there in the oxygen atom? c. Oxygen... A car has a mass of 900 kg. It accelerates from rest at a rate of 1.2 m/s 2 . a. Calculate the time taken to reach a velocity of 30 m/s. b. Calculate the force required to accelerate the car at a... When 0.08 g of liquid X was vaporised at 100 C, 23 cm 3 of vapour was formed. The atmospheric pressure was 1.02 10 5 Pa. Calculate the relative molecular mass of liquid X. (R = 8.31 J K 1 mol 1 ) A car is travelling along a flat road in winter. The car approaches a patch of ice on a bend. Explain why the car cannot go around the perfectly smooth, icy bend. Suggest what might happen if the... Figure 18.18 shows the displacementtime graph for an oscillating mass. Use the graph to determine the following: a. Amplitude b. Period c. Frequency d. Angular frequency e. Displacement at A f.... A mass, hung from a spring, oscillates with simple harmonic motion. Which statement is correct? A. The force on the mass is directly proportional to the angular frequency of the oscillation. B. The... Suppose that the mean daily viewing time of television is 8.35 hours. Use a normal probability distribution with a standard deviation of 2.5 hours to answer the following questions about daily... The probability distribution for damage claims paid by the Newton Automobile Insurance Company on collision insurance follows. Payment ($) ....................... Probability 0... a. What is a catalyst? b. List the properties of catalysts. c. Name the catalyst used in the following processes: (i) The Contact process (ii) The Haber process (iii) The hydrogenation of unsaturated... The following results were obtained from a neutralisation reaction between 1 mol dm 3 hydrochloric acid and 1 mol dm 3 sodium hydroxide. This experiment was carried out to measure the heat of... A ball is kicked at a house window. The window is 4m up a vertical wall from a horizontal floor. The ball is kicked from a position that is 12 m distance from the foot of the wall. If the ball enters... A car is moving on a circular section of road where the road is banked at 25 to the horizontal. The radius of this section of road is 100m. The car has mass 1400 kg and is travelling at 30ms -1 .... The apparatus shown below was set up. Give explanations for the following observations. a. The formation of a white cloud. b. It took a few minutes before the white cloud formed. c. The white cloud... The following diagram shows the three states of matter and how they can be interchanged. a. Name the changes A to E. b. Name a substance which will undergo change E. c. Name a substance which will... The figure shows an oscilloscope trace for a sound wave produced by a loudspeaker. a. Copy the figure and draw the trace for a louder sound of the same pitch. b. It takes 1/50th of a second (0.02 s)... The diagram below shows some of the forces acting on a car of mass 800 kg. a. State the size of the total drag force when the car is travelling at constant speed. b. The driving force is increased to... The diagram shows an aeroplane of mass 3.4 x 10 5 kg accelerating uniformly from rest along a runway. After 26 s it reaches a speed of 65 m/s. a. Calculate i. The acceleration of the aeroplane ii.... a. Diagram 1 below shows a plant cell dividing by mitosis. Only two of the many chromosomes are shown for simplicity. i. What stage of mitosis is shown? ii. Draw prophase for the same cell assuming... Five 0.25 m 2 quadrats were placed randomly in an area of grassland in the UK. The percentage of each quadrat occupied by each species of plant was estimated to the nearest 5% and recorded in the... Use the information in the table to deduce the number of electrons and neutrons in a neutral atom of: a. Vanadium b. Strontium c. Phosphorus. Atom Nucleon number Proton number vanadium 51 23... A beam of electrons is passing close to a highly negatively charged plate. When the electrons pass close to the plate, they are deflected (bent) away from the plate. a. What deflection would you... a. The first ionisation energies of four consecutive elements in the Periodic Table are: sodium = 494 kJ mol 1 magnesium = 736 kJ mol 1 aluminium = 577 kJ mol 1 silicon = 786 kJ mol 1 i. Explain the... a. The table shows the first five ionisation energies for five elements (A to E). For each one state which group the element belongs to. b. Explain your reasoning behind your answer for element E. c.... The sketch graph shows the 13 successive ionisation energies of aluminium. a. Define the term 1st ionisation energy. b. How does the graph provide evidence for the existence of three electron shells... Weekly instruction time for a school student in the United States is 22.2 hours compared to 26.9 hours in China. Is the difference meaningful? How could a graph be constructed so that the difference... Reasoning that barrels of oil are three-dimensional, a newspaper publishes a three-dimensional graph showing oil production (barrels) in five different years For Exercises, determine whether the... a. State what is meant by: i. A couple ii. Torque. b. The engine of a car produces a torque of 200 N m on the axle of the wheel in contact with the road. The car travels at a constant velocity... Compound E has the composition 69.8% carbon, 11.6% hydrogen and 18.6% oxygen. Its mass and 1H NMR spectra are shown below. a. Calculate the empirical formula of E. b. From the mass spectrum, find the... The gasliquid chromatogram for a mixture of organic compounds is shown below. a. Give the correct labels for a, B and C. b. What percentage of the mixture is pentan-1-ol? c. Give an explanation for... Which statement is correct? A. There is a resultant force on an object moving along a circular path at constant speed away from the centre of the circle causing it to be thrown outwards. B. There is... A scatterplot is a graph in which the points are scattered throughout, without any noticeable pattern. In Exercise, determine whether the given statement is true or false. Although it made our study more expensive, we chose a larger sample size in order to have a smaller margin of error. Does It Make Sense? For Exercises, determine whether the statement makes sense (or... Based on our sample, the 95% confidence interval for the mean amount of television watched by adult Americans is 2.5 to 2.7 hours per day. Therefore, 95% of all Americans watch between 2.5 and 2.7... The mobility of a Rb + ion in aqueous solution is 7.92 10 8 m 2 s 1 V 1 at 25C. The potential difference between two electrodes placed in the solution is 35.0 V. If the electrodes are 8.00 mm apart,... The graph in Figure 3.23 depicts U.S. marriage and divorce rates for selected years. The marriage rates are depicted by the blue bars, and the divorce rates are depicted by the maroon bars. The rates... (a) Using a bulk plasmon frequency p of 9 eV, account for the background permittivity b (assumed to be real) that leads to a surface plasmon resonance R of 2.4 eV (b) Assuming p /T is on the... There is a 0.9986 probability that a randomly selected 30-year-old male will live through the year. A life insurance company charges $161 for insuring that the male will live through the year. If he... In seeking to understand the factors that affect a college graduates future income, researchers conducted a multiple regression analysis that examined the effects of major, grade point average, the... Solve Problem 1.5 using trigonometry. Problem 1.5 A fault has the following attitude: 080, 48S. Using orthographic projection, determine the apparent dip of this fault in a vertical cross section... Sketch the focal-mechanism solutions for earthquakes that would be expected to occur at each of the plate boundaries in Problems 17.1 and 17.2 (Fig. G-57). Be sure to label the fault plane, the... a. A geologist studying thrust faults in a Proterozoic shear zone in southern Wyoming developed the hypothesis that all of the thrust faults formed during a regional northnorthwest/southsoutheast... Figure G-7 consists of three geologic maps, each of which has two topographic profiles below it. For each map there are at least two possible interpretations for the contact. Sketch two geologically... In Problems 4148, you need to make some assumptions before you estimate your answer. State your assumptions and then calculate the exact answer. A school in Oakland, California, spent $100,000 in... Suppose you are building a stairway (such as shown in Figure 5.27). Assume that the vertical rise is 8 ft, thehorizontal run is 12 ft, and the maximum rise for each step is 8 inches. How many steps... The white Spirit black bear (or Kermode), Ursus americanus kermodei, differs from the ordinary black bear by a single amino acid change in the melanocortin 1 receptor gene (MC1R). In this population,... Use VEC A modified for the stable 18-electron configuration of Kr to justify the network of Cu tetrahedra in MgCu 2 . From the data in Table 4.6, calculate the mean (i.e., the average) of the Bornstein errors V observed V predicted . What do the results suggest about the merit of the model? Table 4.6 In 1976, Marc... Figure 3.2 suggests that oxidative non stoichiometry of NiO at high temperature is achieved via formation of nickel vacancies and holes. The following data have been measured [5, 6] at 1100 C in O 2... Consider an Ising model with an infinite-range interaction such that each spin interacts equally strongly with all other spins: ^ H = c i < j i j 0 H i i H ^ = c i < j i j 0 H i i... Draw both chair conformations for each of the following compounds. In each case, identify the more stable chair conformation: (a) Methylcyclohexane (b) Trans-1,2-Diisopropylcyclohexane (c)... Below is the structure of caffeine, but its lone pairs are not shown. Identify the location of all lone pairs in this compound: - -N N. .C. Caffeine Z-O- Z-U Propose an efficient synthesis for each of the following transformations. You might find it useful to review Section 11.13 before doing these problems. In section 11.13 Radical halogenation provides... Propose a plausible synthesis for each of the following transformations: a. b. c. d. e. f. g. h. Br Br Suggest an efficient synthesis for each of the following transformations: a. b. Using acetylene as your only source of carbon atoms, identify a synthetic route for the production of 2-bromobutane. Using any reagents you like, show a way to convert 1-methylcyclopentene into 3-methylcyclopentene. Fill in the missing reagents below. Me OEt ?| Br Me SH OEt OMe OEt CN Identify the reagents necessary to achieve each transformation below: (a) (b) (c) D D D Using any compounds that contain two carbon atoms or fewer, show a way to prepare a racemic mixture of (2R, 3S) - and (2S, 3R) -2, 3-dihydroxypentane. Identify the reagents you might use to achieve each of the following transformations: Br Br , En Starting with acetylene as your only source of carbon atoms, identify how you would prepare each member of the following homologous series of aldehydes: a. Ethanal b. Propanal c. Butanal d. Pentanal Cyclopropane (shown below) has only one constitutional isomer. Draw a condensed structure of that isomer. -. - CH2 H2 Propose a structure that is consistent with each of the following 1 H NMR spectra. In each case, the molecular formula is provided. (a) (b) (c) (d) (e) (f) Proton NMR C,H,,0 i ppm Integration Values... A differential dz = f (x, y) dx + g(x, y) dy is exact if the integral f (x, y) dx + g(x, y) dy is independent of the path. Demonstrate that the differential dz = 2xy dx + x 2 dy is exact by... Identify the reagents you would use to achieve each of the following transformations: CI Br Br CH Draw the structures of compounds A to D: NaNH, NaNH, 1) Excess NaNH, Br2 Br2 2) H20 (C3H12) A 1.25 mole sample of an ideal gas is expanded from 320. K and an initial pressure of 3.10 bar to a final pressure of 1.00 bar, and C P,m = 5/2R. Calculate w for the following two cases: a. The... Predict the product and draw the mechanism for each of the following reactions: a. b. c. ? 1) LAH 2) H20 Use resonance structures to help you identify all sites of low electron density (δ+) in the following compound: Starting with cyclohexene and using any other reagents of your choice, show how you would prepare each of the following compounds. a. b. c. OH OMe Based on your analysis in the previous problem, determine whether the following allene is expected to be chiral: Me , Me, c=c=c Me Methylmagnesium bromide reacts rapidly with ethylene oxide, it reacts slowly with oxetane, and it does not react at all with tetrahydrofuran. Explain this difference in reactivity. Oxetane Ethylene... Identify the reagents necessary to accomplish each of the transformations below: (a) (b) Me Using toluene and acetylene as your only sources of carbon atoms, show how you would prepare the following compound. Draw the expected product when each of the following compounds is treated with chromic acid. a. b. c. Predict the major product obtained when each of the following compounds is treated with Birch conditions. a. b. c. d. e. f. OH Draw the two possible enols that can be formed from 3-methyl-2-butanone, and show a mechanism of formation ofeach under base-catalyzed conditions. Prove that a substance for which the solidliquid coexistence curve has a negative slope contracts upon melting. You observe light passing through a slit of width a as decreases from a to a. Will you observe a sharp transition between ray optics and diffraction? Explain why or why not. When a molecule absorbs a photon, momentum is conserved. If an H 2 molecule at 500. K absorbs an ultraviolet photon of wavelength 175 nm, what is the change in its velocity, v? Given that its average... Draw a Lewis dot structure for each of the following atoms: (a) Carbon (b) Oxygen (c) Fluorine (d) Hydrogen (e) Bromine (f) Sulfur (g) Chlorine (h) Iodine Propose an efficient synthesis for the following transformation. Consider the three constitutional isomers of dioxane (C 4 H 8 O 2 ): One of these constitutional isomers is stable under basic conditions as well as mildly acidic conditions and is therefore used as... Propose an efficient synthesis for the following transformation: N. Propose an efficient synthesis for each of the following transformations: (a) (b) (c) (d) (e) (f) (g) (h) Br Identify the starting materials needed to make each of the following acetals: (a) (b) (c) OEt The smallest observed frequency for a transition between states of an electron in a one-dimensional box is 3.0 10 13 s 1 . What is the length of the box? The wave functions p x and d xz are linear combinations of the spherical harmonic functions, which are eigenfunctions of the operators H, l 2 , and l z for rotation in three dimensions. The...
Showing 1300 - 1400 of 4582