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• Question #cdf6c
  
• Given #K_"sp"# #ZnCO_3=1.46xx10^-10#, what is the #"ppm"# concentration of a saturated solution?
  
• Calculate the volume of .00500 M solution needed to make 10.00 ml of the following? .00400 M solution .00300 M solution
  
• Question #c2852
  
• Question #c2449
  
• Assuming #"Ba"("OH")_2# dissociates completely, what is the #"pH"# of #"0.015 M"# #"Ba"("OH")_2# to three sig figs?
  
• Question #f096c
  
• Is #CaCO_3# acidic, basic, or neutral?
  
• What should be the pH after 33 ml of 0.1 M NaOH was added to 40 ml of 0.05 M HCl?
  
• How do you find beta decay?
  
• Question #effe3
  
• What is the empirical formula for a compound which contains 0.0134 g of iron, 0.00769 g of sulfur and 0.0115 g of oxygen?
  
• PH of #0.1(N)CH_3COOH# is what?
  
• Does the number of valence electrons an element has change?
  
• Commercially available concentrated Hcl contains 38% Hcl by mass. (1) what is the molarity of the solution ( density of solution =1.19 g mL -1)? (2) What volume of concentrated Hcl is required is required to make 1.0 L of an 0.10 M Hcl?
  
• Question #b844d
  
• Question #b34ea
  
• Why were Rutherford's students surprised by the results of the gold foil experiment?
  
• What are the products for this reaction: NaOH + Na2S ?
  
• Why is it important in carbon dating to consider the ratio of carbon-14 atoms to other carbon atoms, rather than only the number of carbon-14 atoms?
  
• Molten iron is extremely hot, averaging about 1,500 C. The specific heat of iron is 0.46 J/gC. How much heat is released to the atmosphere when 1 kg molten iron cools to room temperature (25 C)?
  
• Molten iron is extremely hot, averaging about 1,500 C. The specific heat of iron is 0.46 J/gC. How much heat is released to the atmosphere when 1 kg molten iron cools to room temperature (25 C)?
  
• Uranium-235 has a half-life of 700 million years. How long does it take a 100-gram sample of Uranium-235 to decay to a mass of 50 grams?
  
• A mole of O atoms contains how many atoms?
  
• How many hydrogen atoms are in five molecules of #H_2O#?
  
• What is the percent by mass of #NaHCO_3# in a solution containing 50 g #NaHCO_3# dissolved in 750 mL of water?
  
• Question #0ce76
  
• What are first order half life units?
  
• An original sample of K-40 has a mass of 25.00 grams. After #3.9 xx 10^9# years, 3.125 grams of the original sample remains unchanged. What is the half-life of K-40?
  
• Question #42d80
  
• Question #098cc
  
• How do buffers change pH?
  
• Question #816d2
  
• At conditions of 785.0 torr of pressure and 15.0 °C temperature, a gas occupies a volume of 45.5 mL. What will be the volume of the same gas at 745.0 torr and 30.0 °C?
  
• How do you calculate the mass defect and nuclear binding energy per nucleon of each of the nuclides?
  
• Which direction do chloride ions flow when molten #"NaCl"# undergoes electrolysis?
  
• Question #2de37
  
• Question #7b280
  
• Question #f228f
  
• When curium-242 is bombarded with alpha particles, a neutron and what are formed?
  
• Describe Rutherford's model of the atom, including the location of protons, neutrons, and electrons with respect to the nucleus. How does this model explain the deflections of a beam of alpha particles aimed at a sheet of gold foil?
  
• Question #27b1f
  
• Question #ad9a8
  
• The molar heat of fusion for water is 6.01 J/mol. How much energy must be added to a 75.0-g block of ice at 0°C to change it to a 75.0 g of liquid water at 0°C?
  
• #Zn(s) +Ni^(2+)(aq) -> Zn^(2+)(aq) + Ni(s)# Which part of the cell conducts electrons in this reaction and describes the direction of electron flow as the cell operates?
  
• If #14*g# of ammonia was isolated from a reaction between #N_2#, and #H_2#, what is the percentage yield?
  
• How many valence electrons does nickel have?
  
• In the equation: #A + B -> C+D#, what are A and B?
  
• What is the order for the reaction #2"N"_2"O"_5(g) -> 4"NO"_2(g) + "O"_2(g)#?
  
• In a titration, when the number of moles of the hydrogen ions equals of the number hydroxide ions, what is said to have happened?
  
• A student determines the volume, density, and boiling point of three colorless liquids and lists them in the table below. Could any of the liquids be the same substance?
  
• Question #22d95
  
• Question #dcd77
  
• Question #9bb2b
  
• Question #8f05e
  
• Question #b88fc
  
• What is an example a solution practice problem?
  
• In the chemical compound #C_2H_2#, how many pairs of electrons are shared between the two carbon atoms?
  
• How do you do titration problems involving pH?
  
• How do you arrange #NH_4^+, BF_3, H_2O, C_2H_2#, in increasing order of bond angle?
  
• Question #95220
  
• A buffer solution contains 0.20 M #CH_3COOH# and 0.30 M #CH_3COONa# at #25^oC#? (#Ka=1.8 x10^-5#). What is the pH after the addition of (a) 20.0 mL of 0.050 M #NaOH# or (b) 20.0 mL of 0.050 M #HCl# to 80.0 mL of this buffer solution?
  
• Question #5cff2
  
• What are the quantum numbers for Bromine?
  
• What represents the area in an atom where an electron most likely will be found?
  
• Question #56e71
  
• Question #5ecc9
  
• Question #a4cd9
  
• If a #"62.4 g/L"# solution of bovine insulin in an appropriate solvent achieves an osmotic pressure of #"0.305 atm"# at #"298 K"#, estimate the molar mass?
  
• How do you calculate boiling point?
  
• A sample of #N_2O# gas has a density of 2.85 g/L at 298 K. What must be the pressure of the gas (in mmHg)?
  
• What is the final temperature when 50 mL of water at 80°C are added to 25 mL of water at 25°C?
  
• Why is mass defect significant?
  
• Question #d9ce7
  
• What is the chemical formula of #"magnesium chloride"#?
  
• What is the pH of 0.09 M solution of HBr (hydrobromic acid)?
  
• Question #87509
  
• Question #b2438
  
• Question #fdc63
  
• Question #a7eaa
  
• Radioactive decay of #""^40K# atoms in an igneous rock has resulted in a ratio of 25 percent #""^40K# atoms to 75 percent #""^40Ar# and #""^40Ca# atoms. How many years old is this rock?
  
• How do you determine which orbitals are used in hybridization?
  
• Uranium-238 that crystallized at the same tim Earth formed has undergone approximately how many half-lives of radioactive decay?
  
• Question #b5e6f
  
• Le Chatelier's Principle: #N2 (g) + 3H2 (g) -> 2NH2 (g)# ?
  
• Question #eded3
  
• What is the ground-state electron configuration of a neutral atom of aluminum?
  
• Question #fe00e
  
• How is the Henderson-Hasselbalch equation used to calculate the ratio of #H_2CO_3# to #HCO_3^-# in blood having a pH of 7.40?
  
• What causes mass defect?
  
• #CO_2# gas, in the dry state, may be produced by heating calcium carbonate. #CaCO_3 (s)DeltaCaO(s) + CO_2(g)#. What volume of #CO_2#, collected dry at 55 C and a pressure of 774 torr, is produced by complete thermal decomposition of 10.0 g of #CaCO_3#?
  
• Question #8d00e
  
• Question #4bc86
  
• Can atoms of some elements can share three pairs of electrons?
  
• How do we balance the oxidation of chloride anion to give chlorine gas by potassium permanganate?
  
• Use this balanced equation #2C_2H_2 + 5O_2 -> 4CO_2 + 2H2_O + 2599 kJ#. How much energy is needed to produce 42.9 grams of carbon dioxide?
  
• Question #3c6f1
  
• #200# ml solution of #H_2O_2# completely oxidises 125g # Fe^+#. Find out the molarity and volume strength of #H_2O_2#?
  
• Question #79114
  
• Question #399f7
  
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