2. A sample of solid potassium chlorate is heated strongly for 30 minutes. The sample melts, and bubbles of gas escape during the heating. Upon cooling, the heated sample becomes solid. The solid is white in color before and after heating. A sample of unheated solid is dissolved in water and 10 drops of silver nitrate are added. Nothing happens. A sample of the heated solid is also dissolved in water and treated with 10 drops of silver nitrate. The solution becomes very cloudy. What classification should be given to the change that occurs when potassium chlorate is heated?a. Physicalb. Chemicalc. Can't be determined from the observations and tests.Explain your answer.

A student carries out the following experiments and records the following observations.  1.  A few drops of a solution of KOH (aq) is added to a solution of Cu(NO3)2 (aq).  A blue gelatinous solid forms immediately upon addition.   2.   A few drops of a solution of KOH (aq) is added to a solution of NaNO3 (aq).  No changes are observed.  3.  A few drops of a solution of KOH (aq) is added to an unknown solution that could contain Cu2+(aq) and/or Na+(aq) ions (the solution could contain both ions, just one of the ions, or neither ions).  A blue gelatinous solid forms immediately upon addition.   Select all of the answers that are consistent with the data from those 3 experiments.  Group of answer choices The unknown contains Cu2+(aq) and Na+(aq) The unknown contains Cu2+(aq) The unknown contains Na+(aq) The unknown contains neither Cu2+(aq) or Na+(aq)

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How could you have used the color change property of iron(III) chloride to monitor when the reaction had reached completion? You could have added drops of iron(III) chloride directly to the reaction mixture until a change in color occurred. You could have placed a drop of iron(III) chloride directly to the reaction mixture and waited until the color disappeared. You could have placed a drop of reaction mixture every minute in one test tube containing iron(III) chloride until there was no color change. You could have placed a drop of reaction mixture into different test tubes containing iron(III) chloride every minute until there was no color change. Incorrect

A student weighs out 4.16 g of magnesium chloride and adds enough water to make 125.0 mL of solution.  The student then weighs out 8.82 g of sodium phosphate and adds enough water to make 250.0 mL of solution. 25.0 mL of the magnesium chloride solution is combined with 25.0 mL of the sodium phosphate solution. a.      Write a balanced equation for the reaction that occurs (remember to include phases). b.      If a precipitate forms, write the name of the precipitate and calculate the theoretical yield for the precipitate.  If no precipitate forms, calculate the limiting reactant. c.       If the temperature of the solution decreases, is this reaction exothermic or endothermic?

A student is studying the reaction between aqueous solutions of magnesium sulfate and sodium carbonate. a. What compounds would you expect to form in the reaction between solutions of magnesium sulfate and sodium carbonate? b. What precipitate(s) would you expect to observe? c. The student reports that when the magneiums sulfate solutions is added to the sodium carbonate solution a white precipitate forms. Howver, when the student adds sodium solution to the magnesium sulfate solutions no precipitate forms. Does this information make sense? Why or why not?

13. A chemistry student offers a possible improvement to this lab. Since one goal of this lab is to determine the mass of the precipitate produced, wouldn't it be possible to measure the mass of an empty beaker, mix the solutions, and boil off the water until it is entirely evaporated, leaving only solid behind? Then the beaker with the precipitate could be weighed, and the difference between this mass and that of the empty beaker would be the mass of the precipitate. This would eliminate the need for the filtration step. Explain why this is a poor suggestion. Remember to check your reasoning on this question and all other questions with your instructor.

Write a balanced equation for the double-replacement precipitation reaction described, using the smallest possible integer coefficients. A precipitate forms when aqueous solutions of manganese(II) sulfate and ammonium carbonate are combined. Do not include states such as (s) or (aq). It is not necessarry for you to indicate which of the products is the precipitate.

b) Water "softeners" work via the principle of ion-exchange. The tank of a water softener is filled with a soluble salt such as sodium chloride. As "hard" water passes through the tank, the undesirable ions in hard water (e.g., calcium, magnesium, and iron III) are exchanged for the more desirable "soft" (meaning more soluble) ions like sodium. Explain how swapping the "soft"-water sodium ions for "hard"-water ions would influence the behavior (the cleaning effectiveness) of soaps and detergents.

What happens when potassium iodide is added to a solution of lead nitrate? Potassium nitrate precipitates out. Lead iodide precipitates out. Gaseous lead iodide forms. Nothing - there is no reaction between potassium iodide and lead nitrate.