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Combustion of a .225g sample of a compound containing only carbon, hydgrogen and oxygen produces .306g water and .561g carbon dioxide. what is the empirical formula of the compound?
Ammonia rapidly reacts with HCl producing ammonium chloride. Calculate the number of grams of excess reactant when 7.5g NH3 reacts with 4.3g of HCl.
The filter used originally weighed 0.4327 grams. After the sample was filtered and dried at 103C to 105C, the filter was weighed again at 0.4396 grams. Calculate the TSS of the sample.
Some diamonds appear yellow because they contain nitrogen compounds that absorb purple light of frequency 7.46 10^14 Hz. Calculate the wavelength (in nm) of the absorbed light.
Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7
One metric tonne(t) equals 1000kg. What is the amount of sulfur dioxide produced by a power plant that burns 7.5 million metric tonnes(t) of coal over a year? Assume that the coal is 2.4% sulfur
Assume that you are a chemical engineer attempting to optimize the process CO(g) + 2H2(g) (right arrow) CH3OH(g), what conditions would you use? Explain purpose of each factor by applying Le Chai
The half life of an isotope is 3.15 x 104 years. How many hours will it take for a 4.92 g sample to decay until 1.81 g of the isotope remains? Remember - that there are actually 365.25 days in a yea
The end position of the arm must be deteermined accurately in order to weld the components at the precise position. a) In selecting the material for the arm of such robots, what factors must be c
A 0.0125-g sample of a gas with an empirical formula of CHF2 is placed in a 165-mL flask. It has a pressure of 13.7 mm Hg at 22.5 ?C. What is the molecular formula of the compound?
When chemists are preparing dilute acid solutions in water they follow the proverb "Always add acid" Explain why this is a good idea. What would happen if the water is added to the acid?
The Henry's Law constant KH for O2 in water at 20 degrees C is 1.28 x 10-3 mol L-1atm-1. How many grams of O2 will dissolve in 2.0 L of H2O that is in contact with pure O2 at 1 atm?
A 5.05g sample of a copper substance was heated in air and 6.32g of copper II oxide was formed. what was the formula of the orginal copper substance?
In an experiment, 6.00 g of Mg(s) was reacted completely with O2(g) to form MgO(s) and 148.5 kJ of heat was evolved. What is the molar enthalpy in kJ/mol of formation of MgO(s)?
A student titrates a sulfuric acid solution of unknown concentration with 0.15 M sodium hydroxide. The titration requires 34.8 mL of the sodium hydroxide solution to completely neutralize 10.00 mL o
A 10.0 mL sample of household ammonia solution required 33.55mL of 0.450 M HCl to reach neutralization. Calculate (a) the molar concentration of the ammonia and (b) the mass/mass percent concentrati
If the rate of disappearance of N2O5 is equal to 1.60 mol/min at a particular moment, what is the rate of appearance of NO2 at that moment?
A sodium hydroxide solution is standardized using 0.502g of solid oxalic acid, H2C2O4. Find the molarity of the base if 30.50 mL are required for the titration to a phenolphthalein endpoint.
The specific heat of iron is .443 J/g/K. What mass of steam at 100 degrees celcius must be converted to water at 100 degrees celcius to raise the temperature of a 150 g iron block from 25 degrees c
Two determinations of the dissolved oxygen content of a 200 mL sample of water made five days apart, gave 5.3 ppm and 2.2 ppm of dissolved O2, respectively. What is the biological oxygen demand o
An iron meteorite was analyzed for isotopic Argon Content. the amount of 36Ar was 0.200mm3 (STP)per kg of meteorite in each 36Ar atom had been formed by a single cosmic event, how many such events m
A 1.885g solid sample containing some FESO4 is dissolved in water. The resulting solution is acidified and titrated to the endpoint with 20.48 mL of 0.02540 M K2Cr2O7. What is the percent iron(II
Identify the element of lowest atomic number whose electron configuration contains four completely filled sublevels.
A 73.8 gram sample of CaSeO42H2O was heated thoroughly in a porcelain crucible, until its weight remained constant. After heating, how many grams of the anhydrous compound remained?
If your lab partner added slightly too much water in step 5 of preparing the penny solution. Will your final percentage of copper in the penny be too big, too small, or unchanged? clearly explain y