General Chemistry Answers

An empty 1.0 L was filled with 5.0 moles of oxygen and 4.0 moles of nitrogen monoxide. If the amount of NO₂ at equilibrium is 1.5 moles, calculate the equilibrium constant, Kc.

2NO(g)  + O₂(g)     ⇌     2 NO₂ (g)           

For the reaction CH4(g)  +2H2S(g) ⇌  CS2(g)  + 4H2(g)  , Kc = 0.046 at 687oC. In an experiment, 4.00 mol of CH4, 1.00 mol of H2S, 2.00mol of CS2, and 2.00 mol of H2 are mixed in a 500mL vessel. Is the reaction at equilibrium? If not, in which direction is it progressing?

Calculate the value of equilibrium constant Kc when:

a.    N₂ reacts with O₂ to produce NO. At equilibrium, the concentrations of each gas were found to be N₂= 0.45M, O₂= 0.88M, and NO= 0.98M.   N₂ + O₂  ⇌ 2NO

b.    N₂ reacts with H₂ to produce NH₃. At equilibrium, the concentrations were N₂=0.12M, H₂= 0.20M, and NH₃= 0.55M.  N₂ + 3H₂  ⇌ 2NH₃

An ideal gas undergoes a mechanically reversible

process (constant pressure, constant

temperature and adiabatic process. The gas entering a T1=650K and P1=10bar decreases its temperature at constant pressure where V2=2.91x10^-3 m^-3. Then, it went to isothermal process to decrease its pressure. Finally, the gas returns to its initial state. Take CP = 7/2 and CV = 5/2R.

a. T2, P3, V1and V3

b.Q,W,ΔU and ΔH

find the concentration of calcium ion in (in ppm) in a 3.50-g pill that contains 40.5 mg of CA

Calculate the number of moles of oxygen present in 2.0g of Na3PO4

a 17.50mL sample of a gas as at 4.500 atm. what will be the volume if the pressure becomes 1.500 atm, with a fixed amount of gas and temperature?

 How many grams of solute is present in 0.4 moles Magnesium hydroxide, Mg(OH)2 in 550 g water, H2O? The molar mass of Mg(OH)2 is 58 g/mol. 

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 How many mL of 0.250 M HCl would react exactly with 30.0 mL of the 0.150 M solution of Ca(OH)2 solution? The chemical reaction involved is: HCl(aq) + NaOH(aq) → NaCl (aq) + H2O (l) 

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 If 7.5 g of sodium nitrate, NaNO3 is dissolved in 85ml of H2O (density of H2O = 1.0g/ml), calculate the %(wt/wt) concentration of H2O in the solution. 

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 A brand of rubbing alcohol says, it contains 70% (vol/vol) isopropyl alcohol. How many mL of isopropyl alcohol are there in 600 ml of the solution in the bottle? 

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 The label of betadine skin cleanser says 7.5 % solution. Taking it to be % (wt/vol), how many grams of betadine (Providone-Iodine) are present in 50 mL bottle? 

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 Calculate the mole fraction of sulfuric acid (H2SO4) in 8% (wt/wt) aqueous H2SO4 solution (molar masses: H2SO4 = 98 g/mol, H2O = 18 g/mol 

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 Calculate the molar concentration of a solution that contains 23 g of potassium hydroxide. KOH in 250 ml of solution. Molar mass of KOH is 56 g/mol. 

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Salt is often used to melt ice on roads during the winter amd the temperature right now is -4.500°C. How much NaCl would be necessary to melt 1000kg of rice by bringing down the freezing temperature to 4.500°C?