Physical Chemistry Answers

Three moles of an ideal gas (closed system) initially at at 56 °C and 8.00 bar undergoes an irreversible, adiabatic process until the final pressure is 3.00 bar. The work done during the process is -615 J. Calculate ΔSsys and ΔSsurr for the process. CPm = 32.5 J/(K mol)

At 298 K the standard enthalpy of combustion of solid L-valine (C5H11NO2 (s)) to give CO2 (g), H2O (liq) and N2 (g) is ΔcombH° = –2911 kJ/mol. Calculate ΔrxH° and ΔrxU° at 298 K for the following reaction.
C5H11NO2 (s) + HCHO (g) + 4 H2 (g) → 3 C2H5OH (liq) + NH3 (g)

How many water molecules are in a block of ice containing 2.50mol of water (H2O)?

Express the number of molecules numerically.

How many formula units make up 30.6g of magnesium chloride (MgCl2)?
Express the number of molecules numerically.

If 21.3 grams of lithium react with excess water, how many liters of hydrogen gas can be produced at 297 Kelvin and 1.40 atmospheres? Show all of the work used to solve this problem.

2 Li ( s) + 2 H2O (l ) yields 2 LiOH (aq ) + H2 (g )

How many grams of concentrated nitric acid solution should be used to prepare 250mL of 2.0M HNO3? The concentrated acid is 70%HNO3.
(1)90.g concHNO3
(2)70.0gconcHNO3
(3)54.0gconc. HNO3
(4)45.0g conc.HNO3

H2O2+O3=H2O+2O2
H2O2+Ag2O=2Ag+H2O+O2
Role of hydrogen peroxide in above reaction is
(1)oxidising in (a) & reducing in (b)
(2)reducing in (a) &oxidising in (b)
(3)reducing in (a) &(b)
(4)oxidising in (a) & (b)

Volume occupied by 1molecule of water is
Density =1g/cm

Using the inverse square law of radiation, what Geiger counter reading would you get for a radioactive material when you are 3 feet from the source (assume an initial reading of 6300 R at a distance of 1 foot from the source)?