Question

A process is carried out at constant pressure. Given that ∆E is positive and ∆H is negative,

D) the system loses heat and contracts during the process

Which equation represents the reaction that corresponds to the standard enthalpy of formation b of CHCl3 at 25° (∆Hf of CHCl3)?
C) 2 C(s) +H2(g) +3Cl2(g) ---> 2CHCl3(l)

The reaction 4 Ag(s) +O2(g) ---->2AgO(s) favors Ag2O at low temperature, but it favors Ag and O2 at high temperatures. How can this be explained in terms of ∆H and ∆S?
A) ∆H is negative and ∆S is negative

Three identical flasks contain three different gases at standard temperature and pressure. Flask A contains CH4, Flask B contains CO2, flask C contains N2. Which flask contains the largest number of molecules?
D) All the flask contains same # of molecules

Some assumptions from the kinetic molecular theory are listed below. Which one is most frequently cited to explain compressibility of a gas?
D) The volume of the particles is negligible compared to the volume of gas

Answer 1

1.

H=E+PV

where P and V are pressure and volume.

H=E+PV

where H =change in enthalpy ,E =change in internal energy ,V = change in volume.

now E is positive and P is constant so if V is negetive then only H can be negetive.and V will be negetive only if the system contracts.

2.Standard means a specific temp and pressure,1 atm pressure and 298 k temperature .Formation means the product formed DIRECTLY from the elements involved in the chemical equation.Every substance should be in standard state like C,H₂ ,Cl₂ .There is never a compound on the reactand side,only elements.

3.H negetive means system release heat.now according to Le Chatelier's principle when a system experience a disturbance(such as concentration,temperature,pressure change) it will respond to restore a new equilibrium state.This is a exothermic reaction so if the temp is increased reverse reaction will be favorable. so at high temp formation of Ag and O₂ will be favorable

4.According to ''Avogadro's law '' equal volume of all gases at the same temperature and pressure have the same number of molecules. so all flask contains same number of molecules

5.This one is most cited assumption..to explain in a better way you should provide all other alternatives