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    Stoichiometry

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    Analytical Chemistry

    2 AgNo3 (aq) + Na2S (s) ---------->Ag2S (s) + 2 NaNO3 (aq) CaCO3 (s) + HCl(aq) --------------> CO2 (g) + CaCl2 (aq) + H2O (l) If 25.0ml of 0.500M AgNO3 is mixed with 50.0ml of 0.100M Na2S how many grams of Ag2S will form? What will be the resulting molar concentration of NaNO3 left over in the reaction mixture? A che

    Theoretical Mass and Percent Yield

    A) What is the theoretical mass of xenon tetraflouride that forms when 130 grams of xenon is reacted with 100 grams of flourine? b) What is the % yield if only 145 grams of xenon tetrafluoride is actually obtained?

    Decomp of NaN3

    How do you find the # of grams of NaN3 are needed to produce 40 L of nitrogen to fill a container to a pressure of 1.30 atm and a temp. of 28.0*C.

    Molar Mass of Gas

    How do you find the molar mass of a gas .286g in a 125ml container at 60cm of Hg at 25*C?

    Solving Chemical Equations for Excess Reactant

    1. Formaldehyde HCHO, once used as a preservative in biology laboratories, is prepared commercially by the reaction: 2 CH3OH + O2 = 2 HCHO + 2 H2O The percent yield is 84.9% in a manufacturing plant. How much formaldyhyde can be expected from processing 397kg CH3OH? 2. A solution containing 1.63g of barium chloride is

    Cobalt by Volhard

    Cobalt 2+ can be analysed by treatment with a known excess of thiocyanate in the presence of pyridine according to the equation: Co2+ + 4C5H5N + 2SCN- -------> Co(C5H5N)4(SCN)2 (s) The precipitate is filtered off, and the SCN- content of the filtrate is determined by Volhard titration. Lab Results: 25ml of unknown solu

    Finding the Concentration of Whiskey in m/v%

    Add approximately 100cm^3 of water to 10cm^3 of whiskey - then fill up the flask to the 500cm^3 mark with water. Pipette 20cm^3 of this solution into a conical flask containing 70cm^3 of 0.05M acidic solution K2Cr2O7. Titrate the excess unreacted K2Cr2O7 with 24.82cm3 of 0.1268M Fe(II) solution. Find the concentration of the

    Mole Concept in Copper

    (a) How many moles are there in 1.95 x 10^24 atoms of copper? (b) How many moles are there in 85.7g of H2SO4?

    Solving for the De Broglie Wavelength

    1. a) Calculate the De broglie wavelength of a golf ball that is 100.0 g and moving at 30.0 m/s. b) Why does the golf ball look like a ball and not like a beam of light? (hint: where is the wavelength on the em spectrum).

    Calculation mass of alcohol in a solution (volume% is given)

    A mouthwash contains 22.5% alchohol by mass. If the bottle of mouthwash contains 350 mL, what is the mass, in g, of alcohol? Using the (m/v)%= Mass of solute (g)X100 Volume of solution(mL) So far, I have: Step 1. 22.5% alcohol= 22.5g alcohol _________

    Aqueous Solution

    A chemist needs 500 g of a 5% aqueous HCl solution. Describe how to make this solution. Show how to determine the amount of solute and solvent required, including all mathematical formulas and computations. Results must be labeled and include appropriate units for mass.

    Working with Osmotic Pressure

    An aqueous solution of 10 g of catalase an enzyme found in the liver has a volume of 1 liter at 27 degrees Celcius. The solutions osmotic pressure at 27 degree celcius is found to be 0.745 torr. Calculate the molar mass of catalase. could you please explain how you come up with the answer to this problem? Thank-you.

    Combustion Reactions - Thermochemistry

    1. A boiler burns fuel which has the following composition by mass: 82% carbon, 5% hydrogen, 6% oxygen and 7% ash. (a) Find the stoichiometric A/F ratio. If the dry analysis of the products yielded the following composition by volume: 13.2% carbon dioxide, 1.5% carbon monoxide, 6.8% oxygen and 78.5% nitrogen, calculate:

    Basic Chemistry Problems

    Hi, I need some assistance understanding the answers to the following multiple choice questions: 1. The weight of a body varies according to the force of gravity exerted on the body. True False 2. An anion is the a: - Positive pole in an electrical system - Subatomic part of an atom - Molecule with a +1 net charge

    Solids

    Lead has an atomic radius of 175 pm and crystalizes in a face centered cubic structure. Find the mass of the unit cell in grams, the volume of the unit cell in cubic centimeters, and the density of the lead in g/cubic centimeters? I submitted this problem last night and I do not understand how you are getting the measurement

    Mass, Volume and Density of unit cell of lead

    Lead has an atomic radius of 175 pm and crystallizes in a face centered cubic structure. Find the mass of the unit cell in grams, thje volume of the unit cell in cubic centimeters, and the density of lead in g/cubic centimeters?

    Particulates breathed in per day

    If a person breathes in 20m^3 of air per day and the air contains 263 micrograms of particulates per m^3, how many grams of particulates does a person breathe in per day?

    Electronic Spectra in Coordination Chemistry

    The most intense absorption band in the visible spectrum of [Mn(H20)6}2+ is at 24,900 cm-1 and has a molar absorptivity of 0.038 mol -1 cm-1. What concentration of [Mn(h20)6]2+ would be necessary to give an abosorbance of 0.10 in a cell of path length 1.00.

    6 molar solubility

    The Ksubletterssp for silver(l) phosphate is 1.8x10^-18. Calculate the molar solubility of silver phosphate. show all work and all steps. thanks

    Determine how many moles are used.

    In the laboratory you are instructed to add 2 drops of 0.15 M AlCl3 to 2 drops of 0.15 M NaOH. If twenty drops makes one milliliter, determine how many moles of AlCl3 are used. How many moles of NaOH are used?