Elements Beryllium,Magnesium,Calcium, and Strontium are elements in group 2. These elements are relatively reactive-they will react with oxygen,acid and bases. Consequently they are found as minerals and are combined with other elements. What is mineral? These minerals have monetary value to a variety of global industries. Where in the world would you mostly likely find minerals (or pure forms)of each of these elements in groud 2,periods 2-5?
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A metal, M, forms a nitride compound with the formula M3N2. This compound is 84.78 % M by mass and 15.22 % N by mass. Calculate the molar mass of the metal, M.
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Rank the following elements by electron affinity, from most positive to most negative EA value.
cesium, argon, iodine, selenium, arsenic
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Solubility of Gases
8. What is the
saturation concentration of DO
at 10°C in mg/L?
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Write a balanced equation from each line notation:
a) Ag(s)|Ag¹ᐩ(aq)||Cr³ᐩ(aq)|Cr(s)
b)Pb(s)|Pb²(aq)||MnO₂(aq)|Mn²ᐩ(aq)|Pts)
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A 2.2222 gram sample containing soda ash is dissolved in a 100 mL volumetric flask. A 24.98 mL aliquot is analyzed and required 45.67 mL of 0.1234 M HCl, before it was boiled, cooled, and back-titrated with 8.88 mL of 0.0987 M NaOH. What is the percent Na2CO3?
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A 250mL buffer solution is 0.250M in acetic acid and 0.250M in sodium acetate.
A) What is the pH after the addition of 0.005 mol of HCl?
B) What is the pH after the addition of 0.005 mol of NaOH?
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1)Consider the titration of 50.0 mL of 0.20 M NH3 (Kb=1.8
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A chemist titrates 80.0mL of a 0.6050M trimethylamine CH33N solution with 0.2965M HNO3 solution at 25°C . Calculate the pH at equivalence. The pKb of trimethylamine is 4.19 . Round your answer to 2 decimal places. Note for advanced students: you may assume the total volume of the solution equals the initial volume plus the volume of HNO3 solution added.
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Background: A 102.4 mL sample of 0.110 M methylamine (CH3NH2, Kb=3.7×10−4) is titrated with 0.230 M HNO3. Calculate the pH after the addition of each of the following volumes of acid.
A.) 0.0 mL
B.) 24.5 mL
C.) 49.0 mL
D.) 73.5 mL
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. . Ammonium carbamate (molar mass = 78.08 g/mol) decomposes according to the reaction shown below, producing ammonia and carbon dioxide. (NH4)(NH2CO2)(s) ⇌ 2NH3(g) + CO2(g) Kp = 0.400 at 298 K 10.2 g of ammonium carbamate is sealed in an empty 2.00-L vessel and allowed to come to equilibrium at 298 K.
a. What are the partial pressures of NH3 and CO2 at equilibrium? NH3:_______________________________ CO2:_______________________________
b. What mass of solid ammonium carbamate is in the flask at equilibrium? Answer:_______________________________
c. The temperature of the reaction vessel increased to 398 K; when equilibrium is re-established, the total pressure in the vessel is 4.22 atm. Calculate the values of Kp and Kc at this temperature. Kp:_______________________________ Kc:_______________________________
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of the metal ions tested, sodium produces the brightest and most persistent color in the flame. do you think potassium could be detected visually in the presence of sodium by burning this mixture in a flame? could you detect both with a spectroscope?
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An electric stove burner on its highest setting exhibits an orange glow.
A) When the burner setting is changed to low, the burner continues to produce heat but the orange glow disappears. How can this observation be explained with reference to one of the fundamental observations that led to the notion of the quanta?
B) Suppose that the energy provided to the burner could be increased beyond the highest setting of the stove. What would we expect to observe with regard to visible light emitted by the burner?
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Why do line spectra for substances differ? Could line spectra be used to fingerprint emissions?
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A mixture of water and graphite is heated to 600 K . When the system comes to equilibrium it contains 0.11 mol of H 2 , 0.11 mol of CO , 0.31 mol of H 2 O , and some graphite. Some O 2 is added to the system and a spark is applied so that the H 2 reacts completely with the O 2 . Find the amount of CO in the flask when the system returns to equilibrium.
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