Question

In: Chemistry

Cumene, a hydrocarbon, is 89.94% carbon, and its molar mass is 120.2 g/mol. What are the...

Cumene, a hydrocarbon, is 89.94% carbon, and its molar mass is 120.2 g/mol.

What are the

a) empirical and b) molecular formulas for Cumene? Show your work

Solutions

Expert Solution

C%   = 89.94%

H%    = 100-C%

          = 100-89.94

            = 10.06%

Element           %                 A.Wt               Relative numer           simple ratio      simplest ratio

C                  89.94                 12                89.94/12 = 7.495           7.495/7.495 = 1          1*3 = 3

H                 10.06                   1              10.06 /1 = 10.06           10.06/7.495 = 1.342      1.342*3 = 4

               The empirical formula   = C3H4

            Empirical formula mass   = 40g/mole

           molar mass = 120.2 g/mol.

                molecular formula     = (empirical formula)n

                                    n       = molar mass/empirical formula mass

                                              = 120.2/40   = 3

molecular formula   = (C3H4)3   = C9H12


Related Solutions

Squalene, a hydrocarbon, is a compound composed only of C and H. It is 87.73% carbon, and its molar mass is 410.7 g/mol.
Squalene, a hydrocarbon, is a compound composed only of C and H. It is 87.73% carbon, and its molar mass is 410.7 g/mol. What are the empirical and molecular formulas of squalene? Empirical formula: Molecular formula:An unknown compound has the formula CxHyOz. You burn 0.2573 g of the compound and isolate 0.6282 g of CO2 and 0.2572 g of H2O. What is the empirical formula of the compound? If the molar mass is 72.1 g/mol, what is the molecular formula? (Enter the...
Chem Question - Gases Molar Mass N = 14.01 g/mol Molar Mass H2O = 18.016 g/mol...
Chem Question - Gases Molar Mass N = 14.01 g/mol Molar Mass H2O = 18.016 g/mol Vapor Pressure of Water at 25 C is 23.76 torr Vapor Pressure of Water at 65 C is 187.54 torr (Show all work and calculations, include units in answer. If calculations must be used in several parts, rounding should be made to 6 decimal points to ensure accuracy. Final Answers can be rounded to 3 decimal points.) A syringe filled with air can be...
What mass of a weak acid with a molar mass of 100 g/mol is necessary to...
What mass of a weak acid with a molar mass of 100 g/mol is necessary to neutralize 25 ml of 0.10 M NaOH solution? What is the pH of 0.15 g of sodium acetate NaC2H3O2 in 100 ml water H2O?
The vapor pressure of pure carbon tetrachloride, CCl4, (molar mass 153.82 g/mol) is 0.354 atm, and...
The vapor pressure of pure carbon tetrachloride, CCl4, (molar mass 153.82 g/mol) is 0.354 atm, and the vapor pressure of pure chloroform, CHCl3 (molar mass 119.38 g/mol), is 0.526 atm at 316 K. A solution is prepared from equal masses of the two compounds at this temperature. If the vapor over the original solution is condensed and isolated into a separate flask, what with the vapor pressure of the chloroform be above this new solution?
What mass (in g) of iron (Fe, molar mass = 55.85 g∙mol–1) is needed to experimentally...
What mass (in g) of iron (Fe, molar mass = 55.85 g∙mol–1) is needed to experimentally produce 50.0 g of iron(III) oxide (Fe2O3, molar mass = 159.70 g∙mol–1) in excess oxygen if the percent yield is 78.7%? 4Fe(s) + 3O2(g)2Fe2O3(s) A. 22.2 g B. 27.5 g C. 35.0 g D. 44.4 g
What is the molecular formula for a compound having a molar mass of 90.04g/mol containing carbon,...
What is the molecular formula for a compound having a molar mass of 90.04g/mol containing carbon, hydrogen, and oxygen? Combustion analysis reveals .501g of CO2 and .103 grams of water from burning .514 grams of the compound.
Ethanol, C2H5OH (molar mass = 46 g/mol) is mixed with methanol, CH3OH (molar mass = 32...
Ethanol, C2H5OH (molar mass = 46 g/mol) is mixed with methanol, CH3OH (molar mass = 32 g/mol) to make an ideal solution at a given temperature. If 5.00 g of ethanol and methanol are mixed, what is the resulting vapor pressure of the solution? (the vapor pressure at the same temperature for pure ethanol is 44.5 mm Hg and pure methanol is 88.7 mm Hg)
A compound has a molar mass of 100 g/mol and the percent composition (by mass) of...
A compound has a molar mass of 100 g/mol and the percent composition (by mass) of 65.45% C, 5.45% H, and 29.09% O. Determine the empirical formula and the molecular formula.
A 0.520 g sample of a diprotic acid with a molar mass of 255.8 g/mol is...
A 0.520 g sample of a diprotic acid with a molar mass of 255.8 g/mol is dissolved in water to a total volume of 23.0 mL . The solution is then titrated with a saturated calcium hydroxide solution. a. Assuming that the pKa values for each ionization step are sufficiently different to see two equivalence points, determine the volume of added base for the first and second equivalence points. b. The pH after adding 23.0 mL of the base was...
What is the mass of one molecule of cholesterol C2H6O? molar mass/g mol-2 C2H6O 387 a....
What is the mass of one molecule of cholesterol C2H6O? molar mass/g mol-2 C2H6O 387 a. 4.3x10^-27g b. 1.7 x 10^-24g c. 6.4x 10^-22g d. 2.6 x 10^-3g
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT