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169 g FeCr2O4, 298 g K2CO3 and an excess of O2 (g) are sealed in a reaction vessel and allowed to react at high temperature. The amount of K2CrO4 obtained is 194 g. Calculate the percent yield of K2CrO4.
4 FeCr2O4 + 8 K2CO3 + 7 O2 → 8 K2CrO4 + 2 Fe2O3 + 8 CO2
( Molar mass: FeCr2O4 = 223.84, K2CO3=138.21, K2CrO4 =194.19 g/mole )
The percent of aluminum in the compound, Al2X3, is 18.56 %. What is the molar mass of element X ?
An alloy of Co, Rh and Mn contains these elements in the atomic ratio of 2 : 5 : 2 , respectively. What is the mass of a sample of this alloy containing a total of 8.75 x 1021 atoms ?
A sulfur containing compound is treated chemically to convert all its sulfur into barium sulfate. A 8.19 mg sample of the compound gave 5.46 mg barium sulfate.
What is the percentage of sulfur in the compound?
If there is one sulfur atom in the molecule, what is the molar mass of the compound ?
Identify the most appropriate class (based on purity) of chemical/reagent that will be used in the following:
1. Quantitative analysis of caffeine in soft drinks via chromatographic method. Caffeine will be used as a standard. What class of caffeine should be used for the analysis? Explain your
answer.
2. The required mobile phase for the analysis caffeine in soft drinks in liquid chromatography are methanol and water. What class of methanol and water must be used? Explain your
answer.
3. Ethanol is needed as solvent when preparing phenolphthalein color indicator in volumetric titrations. What class of ethanol best suits the intended purpose? Explain your answer.
4. A purifying agent is required in sugar industry to clarify extracted cane juices. What class of purifying agent must be used? Explain your answer.
5. One of the raw materials for the production of herbal medicine power is ethanol. What class of ethanol should be used for extraction? Explain your answer.
Give me 5 examples of Heterogeneous Mixture and Homogeneous Mixture
A box has dimension 0.2mx0.4m x 0.6m what is the volume of the box in cubic meter ? Round to the nearest hundredth
295 gram Rubidium Oxide reacted with 202 gram calcium cyanide to produce Rubidium cyanide and Calcium Oxide. Find
a)gram of Calcium oxide
b) gram of excess reactant used up
c) gram of excess reactant that remained unreacted
