Chemistry

An electron microscope focuses electrons through magnetic lenses to observe objects at higher magnification than is possible with a light microscope. For any microscope, the smallest object that can be observed is one-half the wavelength of the radiation used. Thus, for example, the smallest object that can be observed with light of 400 nm is 2 x 10 m. (a) What is the smallest object observable with an electron microscope using electrons moving at 5.5 x 10 m/s? (b) At 3.0 x 10 m/s?
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What would be the valence electron configuration of...1) Co^2+2) N^3-3) Ca^2+
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As a technician in a large pharmaceutical research firm, you need to produce 300. mL of 1.00 M a phosphate buffer solution of pH = 7.36. The pKa of H2PO4 is 7.21. You have 2.00 L of 1.00 M KH2PO4 solution and 1.50 L of 1.00 M K2HPO4 solution, as well as a carboy of pure distilled H2O. How much 1.00 M KH2PO4 will you need to make this solution?
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A 50 W engine generates 50 J of energy. How long did it run for? A. 10 s B. 1 s C. 5 s D. 100 s
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If one force on an object on an object is 5N upward and the other obect is 10N downward, what is the object's motion ?
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What is the molarity of the resulting solution when 23.640 g of Mn(ClO4)2 6 H2O are added to 200.0 mL of water? WebAssign will check your answer for the correct number of significant figures. .326 Incorrect: Your answer is incorrect.
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Many calculators use photocells to provide their energy. Find the maximum wavelength needed to remove an electron from silver ( = 7.59 x 10 J). Is silver a good choice for a photocell that uses visible light?
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There are some exceptions to the trends of first and successive ionization energies. For each of the following pairs, explain which ionization energy would be higher:(a) IE of Ga or IE of Ge (b) IE of Ga or IE of Ge(c) IE of Ga or IE of Ge (d) IE of Ga or IE of Ge
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N2(g) + 3 H2(g) 2 NH3(g) + EnergyFor the reaction of nitrogen gas and hydrogen gas to make methane, what stresses would shift the equilibrium to the left toward the reactants?
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A city water district wants to encourage local businesses and homeowners to landscape with drought-tolerant plants. After disappointing results from a publicity campaign, the water district decides to subsidize local plant nurseries so they can offer the plants at a lower price.Suppose the graph shows the supply and demand curves for a drought-tolerant plant, such as purple sage. Drag the appropriate curve to show the impact of the water district subsidy.
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Ammonia is oxidized to nitric oxide in the following reaction: 4NH3 + 5O2 --------> 4NO + 6H2O a. Calculate the ratio (lb-mole O2 react/lb-mole NO formed). b. If ammonia is fed to a continuous reactor at a rate of 100.0 kmol NH3/h, what oxygen feed rate (kmol/h) would correspond to 40.0% excess O2?c. If 50.0 kg of ammonia and 100.0 kg of oxygen are fed to a batch reactor, determine the limiting reactant, the percentage by which the other reactant is in excess, and the extent of reaction and mass of NO produced (kg) if the reaction proceeds to completion.
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Consider the following multistep reaction: C+DCD(fast) CD+DCD2(slow) CD2+DCD3Based on this mechanism, determine the rate law for the overall reaction.
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A chemist dissolves of pure barium hydroxide in enough water to make up of solution. Calculate the pH of the solution. (The temperature of the solution is .) Round your answer to significant decimal places.
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What type of particles flow between objects when they are charged by friction or conduction? A. protons B. quarks C. neutrons D. electrons
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What is the osmotic pressure of a solution formed by dissolving 44.3 mg of aspirin (C9H8O4) in 0.358 L of water at 25 C?
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You conduct an experiment in which you measure the temperature (T) and volume (V) of a mysterious sphere of gas at several different temperatures. The sphere can expand or shrink to any volume without changing the pressure of the gas inside. As a result of your experiment, you find that the volume (V) of the gas divided by its temperature (T) is always equal to 1.75. What would the volume (V) of the gas be at a temperature of 300K? (assume the unit for volume is liters) Show your work and answer the question with a clear statement. Show each step of your calculations for full points. After showing your calculations, answer the question with a clear statement.
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A substance is found to be reactive, flammable, soluble, and explosive. Which of these observations is a physical property? A. reactive B. explosive C. flammable D. soluble
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A 0.510m aqueous solution of KBr has a total mass of 67.0 g. What masses of solute and solvent are present?
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Select the correct answer. What is heat of vaporization? A. It is the heat required to change a substances temperature by 1C. B. It is the heat required to change a gram of substance from a solid to a liquid. C. It is the heat required to change a substance from a solid directly to a gas. D. It is the heat required to change a gram of substance from a liquid to a gas. E. It is the heat required to separate one substance into two substances.
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State the number of solutions for Matrix B. a. No Solution b. One Solution c. Infinitely Many Solutions
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A first order reaction has a rate constant of 0.816 at 25 oC. Given that the activation energy is 22.7 kJ/mol, calculate the rate constant at 34 oC. (enter answer to 3 decimal places)
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Which event signals the birth of a star?
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What happens when an acid dissolves?A. Oxygen is added to the solution.B. It is no longer an acid,C. Hydrogen gas is released,D. H increases in solution.
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How many moles of sebacoyl chloride do you have if you measure out 5 mL of a 9% volume/volume solution in cyclohexane?
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