CHEM 121 Lab exam 2 study

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Which of the following is the correct formula for potassium hydrogen tartrate?
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Which of the following is the correct formula for potassium hydrogen tartrate?
KHC4H4O6
Which of the following is the correct Ksp expression for cream of tartar (potassium hydrogen tartrate)?
Ksp = [K+] [HC4H4O61-]
According to the website, https://pubchem.ncbi.nlm.nih.gov/compound/23681127, what is the solubility of potassium hydrogen tartrate at room temperature?
1 g/ 162mL
What are the products for the equation describing the acidic behavior of hydrogen tartrate in water
HC4H4O61-(aq) + H2O ↔ ?
H3O+(aq) + C4H4O62-(aq)
Which of the following is the correct Ka expression for cream of tartar (potassium hydrogen tartrate)?
Ka = [H3O+] [C4H4O62-]/[HC4H4O61-]
A titration is an analytical technique that requires accurate measurements. Which of the statements below is not proper use of lab equipment or technique?
A: It is okay to use dirty glassware, as long as you know that there will be no reaction with the acid or the base in your titration.
B:To weigh the mass of KHP, place a piece of weighing paper or a small container on the balance tray, zero the scale, then add the KHP.
C: If you accidently weigh out too much KHP, it is never appropriate to return the excess mass to the reagent bottle.
D: To properly use the pipet, always draw the liquid a bit past the desired line, then slowly drain until the liquid level is where you want it.
A: It is okay to use dirty glassware, as long as you know that there will be no reaction with the acid or the base in your titration.
What reagent is used to separate carbonate and sulfite from halides, sulfate, and phosphate?
6 M HNO3
What reagent is used to separate halides from sulfate and phosphate?
0.1 M AgNO3
What reagent is used to separate AgCl from AgBr and AgI?
6 M NH3
A solution is thought to contain one or more of the following ions: CO32-, Cl1-, Br1-, I1-. Several drops of 6 M HNO3 are added but no gasses are evolved. To the solution is added several drops of 0.1 M AgNO3 and a white precipitate is formed. This precipitate dissolves completely in 6 M NH3.
What ion or ions are present?
Cl^1-
True or false. When water is to be used in this lab experiment, it is okay just to use tap water.FalseAccording to the webiste, http://www.public.asu.edu/~jpbirk/, a simple way to keep stirring rods clean is to place them in a beaker of clean distilled water and swirl them about after each use. The contamination will be highly diluted and can remain in the water.TrueAfter a precipitate has been centrifuged and the supernatant liquid decanted or drawn off, there is still a little liquid present in the precipitate. How can you ensure that there will be no ions left in the supernatant liquid that might interfere with future testing?Add the distilled water to the precipitate, stir well, centrifuge, and decant the liquid. This is called washing the precipitate.In this experiment you will use many test tubes. How do you properly dispose of broken glass?Sweep up the broken glass using the broom and dustpan and dispose of in the broken glass container.Proper lab attire includes which of the following:long hair tied bac, shirts that cover the belly and as much of the arms as possible, and long pants or a long skirtIn the qualitative anion experiment, a bright yellow precipitate was produced by adding which compound(s) to the phosphate containing solution?nitric acid and ammonium molybdateis Na3PO4(aq) an acid or basebaseIf a solution of a compound with an extinction coefficient of 532 cm-1M-1 in a 1 cm cuvette has an absorbance of 0.723, what is its concentration in M?0.0014Which of the following statements is/are true about Le Châtelier's principle?If a system in equilibrium is disrupted, the equilibrium will change to counteract the affect of the disturbance., Changes in concentration of reactants or products and temperature can have an affect on the equilibrium of a reaction.For questions 2-5 use the following reaction to state whether the equilibrium will shift right, left or be unchanged upon the addition of the following substances. Chromate ion is yellow, under acidic conditions it is in equilibrium with the dichromate ion which is orange. 2 CrO42- + 2 H+(aq) ↔ Cr2O72-(aq) + H2O ΔH < 0 kJ yellow orange State how the addition of nitric acid will affect an equilibrium mixture of chromate and dichromate ion.The equilibrium will shift rightState how the addition of sodium hydroxide will affect an equilibrium mixture of chromate and dichromate ion.The equilibrium will shift leftState how the addition of K2Cr2O7 will affect an equilibrium mixture of chromate and dichromate ion.The equilibrium will shift leftState how placing the reaction in a ice bath will affect an equilibrium mixture of chromate and dichromate ion.The equilibrium will shift rightFor questions 6-9 use the following reaction to state whether the equilibrium will shift right, left or be unchanged upon the addition of the following substances. Transition metals form complex ions with a variety of species. These complex ions are generally soluble in water and brightly colored and therefore able to be observed easily. For example when nickel(II) nitrate is dissolved in water, the nickel(II) ion becomes hydrated. Nickel(II) ion also forms a complex ion with four CN1- ions, as shown in the following equilibrium equation. Ni2+(aq) + 4 CN1-(aq) ↔ [Ni(CN)4]2-(aq) + 6 H2O green orange State the effect that adding NaCN will have on the equilibrium mixture.The equilibrium will shift rightState the effect that adding Na2CO3 will have on the equilibrium mixture. (Consider the reaction of the carbonate ion with nickel(II) ion)The equilibrium will shift leftState the effect that adding AgNO3 will have on the equilibrium mixture. (Consider the reaction of the silver ion with cyanide ion)The quilibrium will shift leftState the effect that placing the reaction in boiling water will have on the equilibrium mixture. (Assume the reaction is endothermic)The equilibrium will shift rightOne of the stressors that you will use in this experiment is an increase in temperature. Which of the following statements is true when working with hot substances?Always use test-tube clamps to hold hot test tubes.