Organic Chemistry Group Tutoring

09/27/2024

How much work is done by an ideal gas in expanding isothermally from an initial volume of 3.00 liters at 20.0 atm to a final volume of 24.0 liters?

09/09/2024

A 7.85-g sample of a compound with the empirical formula C5H4 is dissolved in 301 g of benzene. The freezing point of the solution is 1.05 C below that of pure benzene.

What are the molar mass and molecular formula of this compound?

09/08/2024

Ethylene glycol (EG), CH2(OH)CH2(OH), is a common automobile antifreeze. It is water soluble and fairly nonvolatile (b.p. 197 C). Calculate the freezing point of a solution containing 651 g of this substance in 2505 g of water. Would you keep this substance in
your car radiator during the summer? The molar mass of ethylene glycol is 62.01 g.

08/31/2024

The density of a 2.45 M aqueous solution of methanol (CH3OH) is 0.976 g/mL. What is the molality of the solution? The molar mass of methanol is 32.04 g.

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07/16/2024

Estimate the enthalpy change for the combustion of hydrogen gas:

2H2(g) + O2(g) ---> 2H2O(g)

Hence, H2O is a polyatomic molecule, and so we need to use the average bond enthalpy value for the O-H bond.

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07/09/2024

Sulfur (S) is a nonmetallic element that is present in coal. When coal is burned, sulfur is converted to sulfur dioxide and eventually to sulfuric acid that gives rise to the acid rain phenomenon. How many atoms are in 16.3 g of S?

06/17/2024

06/11/2024

Calculate the wavelength of the “particle” in the following two cases:

a) The fastest serve in tennis is about 150 miles per hour, or 68 m/s. Calculate the wavelength associated with a 6.0 x10^-2 kg tennis ball traveling at this speed.

b) Calculate the wavelength associated with an electron 9.1094X10^-31 kg moving at 68 m/s.

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06/09/2024

What is the wavelength of a photon (in nanometers) emitted during a transition from the ni =5 state to the nf = 2 state in the hydrogen atom?

06/07/2024

The wavelength of the green light from a traffic signal is centered at 522 nm. What is
the frequency of this radiation?

06/01/2024

A 466-g sample of water is heated from 8.50 C to 74.60 C. Calculate the amount of
heat absorbed (in kilojoules) by the water.

05/31/2024

A quantity of 1.00  102 mL of 0.500 M HCl was mixed with 1.00  102 mL of 0.500 M NaOH in a constant-pressure calorimeter of negligible heat capacity. The initial temperature of the HCl and NaOH solutions was the same, 22.50 C, and the final temperature of the mixed solution was 25.86C. Calculate the heat change for the neutralization reaction on a molar basis.

NaOH (aq) + HCl (aq) ===> NaCl (aq) + H2O (l)

Assume that the densities and specific heats of the solutions are the same as for water (1.00 g/mL and 4.184 J/gC, respectively).