C. the expansion of the universe is accelerating
Explanation:
i think the answer is....b
Answer:
C. T>617 K
Explanation:
We are given that
![\Delta H=176KJ/mol](https://tex.z-dn.net/?f=%5CDelta%20H%3D176KJ%2Fmol)
![\Delta S=0.285KJ/K\cdot mol](https://tex.z-dn.net/?f=%5CDelta%20S%3D0.285KJ%2FK%5Ccdot%20mol)
We have to find the temperature at which the reaction is spontaneous.
When
![\Delta H>0, \Delta S>0](https://tex.z-dn.net/?f=%5CDelta%20H%3E0%2C%20%5CDelta%20S%3E0)
Therefore, the reaction is spontaneous at certain range of temperature.
Option A is not true.
![\Delta G=\Delta H-T\Delta S](https://tex.z-dn.net/?f=%5CDelta%20G%3D%5CDelta%20H-T%5CDelta%20S)
When
is negative, then the reaction is spontaneous.
![\Delta G=176-0.285T](https://tex.z-dn.net/?f=%5CDelta%20G%3D176-0.285T)
When T<50
Suppose T=49 K
![\Delta G=176-49\times 0.285>0](https://tex.z-dn.net/?f=%5CDelta%20G%3D176-49%5Ctimes%200.285%3E0)
Therefore,
.Hence, the reaction is not spontaneous.
Option B is wrong.
C.T>617K
Suppose T=618 K
![\Delta G=176-0.285\times 618=-0.13](https://tex.z-dn.net/?f=%5CDelta%20G%3D176-0.285%5Ctimes%20618%3D-0.13%3C0)
Therefore,
.Hence, the reaction is spontaneous.
So, option C is true.
D.T<617 K
Suppose T=616 K
![\Delta G=176-0.285\times 616=0.44>0](https://tex.z-dn.net/?f=%5CDelta%20G%3D176-0.285%5Ctimes%20616%3D0.44%3E0)
Therefore,
.Hence, the reaction is not spontaneous.
So, option D is not true.
Rock is a combination of two or more minerals, and it does not possess any specific chemical composition. It is present naturally in the environment. Some examples of rocks are limestone, granite, etc.,Limestone may contain minerals like calcite and aragonite. Each mineral has a specific chemical composition with a well defined crystalline structure.
Therefore, the correct option would be a. rock as rock is the naturally occurring solid mass made up of different types of minerals.
<span>Iodine is the element </span><span>has atoms that can form halide atoms.
Answer: Letter A
Hope that helps! -UF aka Nadia</span>