Master Chemistry with Fun Quizzes & Brain Teasers!

balanced ionic equation: a precipitate of barium sulfate forms when aqueous solutions of barium nitrate and potassium sulfate are mixed.
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Helen goes to the doctor and has a thyroid test done. She receives 20 grams of radioactive iodine. After 8 hours, 10 grams of the iodine have broken down. After 16 hours, there are 5 grams of iodine left.What is the half-life of the radioactive iodine?8 hours
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Which two elements are in the same period?Ofluorine and chlorinenitrogen and bismuthmagnesium and phosphorussilver and calciumOO
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A student made measurements on some electrochemical cells and calculated three quantities: The standard reaction free energy DeltaG degree. The equilibrium constant K at 25.0 degreeC The cell potential under standard conditions E degree His results are listed below. Unfortunately, the student may have made some mistakes. Examine his results carefully and tick the box next to the incorrect quantity in each row, if any.
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arrange the compounds in order of decreasing solubility in water. a) 1-butanthiol b) 1-butanol c) 1,2-propanediol
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substituting certain f atoms in xef4 for other halogens could affect the polarity of the molecule. which of these other molecules could be either nonpolar or polar?
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How many compounds, of the ones listed below, have hydrogen bonding?CH3CH2CH2NH2 CH3CH2NHCH2CH3 (CH3CH2)2NCH2CH32130
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Identify each statement as True or False. a) The value of K_w applies to any aqueous solution, not just pure water b) Ions that appear on both sides of an equation but undergo no change in a reaction are called spectator ions. c) An aqueous solution containing an equal number of moles of NaF and HF in an aqueous solution is an example of a buffer solution. d) A solution containing a low concentration HCl is a weak acid.
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Scientists improved Mendeleevs early periodic table by ___.including physical properties of elements such as melting point and densityincluding chemical properties of elements such as the ability to burn or to tarnishusing atomic number instead of atomic mass to organize the elementsusing numbers of neutrons and protons to organize the elements by their properties
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The molecular formula for glucose is C6H12O6. What would be the formula for a polymer made by linking ten glucose molecules together by dehydration reactions?AC20H120060BC60H100050CC60H102051D C60H111051
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An electron and a proton are each accelerated from rest through a potential difference of 100 V. Afterward, which particle has the larger de Broglie wavelength? Afterward, which particle has the larger de Broglie wavelength? A. electron b. proton c. The electron and the proton have the same de Broglie wavelength.
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Two compounds might have spots with the same Rf value in a TLC experiment and not be identical compounds.Which proposed TLC experiment could best help determine whether the compounds are identical?Select one:Repeat the original experiment with a mixture of the compounds in a single spotRepeat the original experiment with larger spots of each compoundRepeat the original experiment with a different solvent systemRepeat the original experiment with the development chamber jar open
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descrie what would happen in the follopwing situations. in the reaction h2so4 (aq) h hso4 the ph has been increased
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If equal masses of O2 and N2 are placed in separate containers of equal volume at the same temperature, which of the following statements is true? If false, explain why it is false.(a) The pressure in the flask containing N2 is greater than that in the flask containing O2(b) There are more molecules in the flask containing O2 than in the flask containing N2
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Consider the following statements: (I) In any energy conversion, some of the usable energy is always lost (II) Energy is neither created nor destroyed, but it may be converted from one form to another, (III) Systems will go spontaneously in one direction only, toward increasing entropy. Which of these are statements of the second law of thermodynamics?a. II and IIIb. I, II, and IIIc. I and IId. I and III
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Suppose17.0gof potassium acetate is dissolved in250.mLof a0.30Maqueous solution of sodium chromate.Calculate the final molarity of acetate anion in the solution. You can assume the volume of the solution doesn't change when the potassium acetate is dissolved in it.Be sure your answer has the correct number of significant digits.
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Use Pauling's rules to arrange the compounds according to their relative acidities in the box below. Assume that the acids are in a non leveling solvent.Strongest Acid - Lowest AcidH2SO4 HIO4 HClO3 HNO2
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Draw structural formulas for the product formed by treating each compound with propylmagnesium bromide followed by aqueous HCl.(a) CH2O(b) (c) (d)
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your hair stays wet after shower , molecules of water are actually sticking to your hair -explains why soil is able to hold water (and form mud).this property is sticking of water with unlike substance :
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curved arrows are used to illustrate the flow of electrons. follow the arrows to predict the intermediate and product of reaction nah
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study this chemical reaction: ca(s) zncl2(aq)zn(s)cacl2(aq) then, write balanced half-reactions describing the oxidation and reduction that happen in this reaction
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if the attractive forces between the ions and water are stronger than the attraction between the ions in the crystal, an ionic compound dissolves in water.
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the binding forces in each solid are responsible for certain properties associated with each type of solid. true or false
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In a freezing point depression experiment, 1.25 grams of an unknown compound is dissolved in 50.0 grams of carbon tetrachloride, CCl4. The resulting freezing temperature of this mixture was -26.52 degrees Celsius. What is the molar mass of this unknown compound? Kf(CCl4) = 29.9 degrees Celsius/m; Freezing point(CCl4) = -22.90 degrees Celsius.
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