Thermodynamics ...

An imaginary reaction $$X\rightarrow Y$$ takes place in three steps $$X\rightarrow A,\Delta H=-q_{1}$$; $$B\rightarrow A,\Delta H=-q_{2}$$; $$Y\rightarrow B,\Delta H=-q_{3}$$ If Hess' law is applicable, then the heat of the reaction $$ X \rightarrow Y $$ is:

The spontaneous nature of a reaction is impossible only if:

Which of the following set of condition necessarily implies a spontaneous process? 

Which of the natural process is spontaneous?

Choose the correct statement.

Consider the following reaction,
$$2A + B \rightarrow C + 2D$$, $$\Delta H_{1} = 10$$
$$A + 2C \rightarrow 2D + B$$, $$\Delta H_{2} = -5$$ What is $$\Delta H$$ of reaction $$A + 2B \rightarrow 3C$$?

At $$300 \,K$$, the reactions which have following values of thermodynamic occurs spontaneously

Consider the following sequence of reactions 
Which of the following is always true?

The pressure at the base of a column of liquid of length / and held at an angle $$\theta $$ to the vertical is 

Calculate the amount of heat necessary to raise $$213.5 g$$ of water from $${25}^{o}$$ and $${100}^{o}C$$ Molar heat capacity of water is $$18 cal$$ $${mole}^{-1}{K}^{-1}$$