Calculatethenumberofmoleculespresentin0.25molesofwater(H2O).
Numberofmolecules=Numberofmoles×Avogadro'snumber=0.25mol×6.022×1023molecules/mol=1.505×1023moleculesTherefore,thenumberofmoleculespresentin0.25molesofwaterare1.505×1023.
Consider a 70% efficient hydrogen-oxygen cell working under the standard condition at 1bar and 298K. Its cell reaction is
H2g+12O2g→H2Ol
The work derived from the cell on the consumption of 1.0×10-3molofH2(g) is used to compress 1.00mol of a monoatomic ideal gas in a thermally insulated container. What is the change in the temperature (in K) of the ideal gas?
The standard reduction potentials for the two half-cells are given below
O2g+4H+aq+4e-→2H2Ol, E0 = 1.23V
2H+aq+2e-→H2g, E0 = 0.00V
Use F=96500Cmol-1, R=8.314Jmol-1K-1.
The hardness of a water sample containing 10-3MMgSO4 expressed as CaCO3 equivalents (in ppm)is (molar mass of MgSO4is 120.37g/mol)
The 8.9M H2O2at 273K and 1atm its volume strength will be—R=0.0821LatmK-1mol-1(Round it off to the nearest integer)
Cassiterite when reduced with coke Tin is obtained. What is the minimum temperature needed for the reduction of cassiterite would take place?
At 298 K ∆fH°=SnO2S=-580.0kJmol-1,∆fH°CO2g=-394.0kJmol-1
S°SnO2(s)=56.0JK-1mol-1,S°Sns=52.0JK-1mol-1
S°Cs=6.0JK-1mol-1,°CO2g=210.0JK-1mol-1
Assume that enthalpies and entropies are temperature independent.