Answer : The correct option is, (b) 22.5 M
Explanation : Given,
Mass of calcium nitrate tetrahydrate = 266 g
Molar mass of calcium nitrate tetrahydrate = 236.15 g/mole
Volume of solution = 
Molarity : It is defined as the moles of solute present in one liter of solution.
Formula used :

Now put all the given values in this formula, we get:

As calcium nitrate tetrahydrate dissociate to give 1 mole of calcium ion, 2 moles of nitrate ion and 4 moles of water.
The concentration of nitrate ion = 
Thus, the concentration of nitrate ion is, 22.5 M
I will have to say that this statement is true
Both indicate the temperature at which the solid and liquid states of a substance are in equilibrium would be your answer.
This is beacause the melting point of a substance is the same as the freezing point of a substance. At this particular temp, the substance can be either a solid or a liquid.
hope this helps!
Answer:
Si una reacción química libera energía, se llama reacción exotérmica. El ejemplo más común es la combustión, en la cual la energía se manifiesta en forma de calor y luz. Si, por el contrario, la reacción química requiere energía del medio para efectuarse, recibe el nombre de reacción endotérmica.
Answer: The layers of the rocks in one region of the parks are smooth and distinct, which are evidence of many, many years of deposition. The layers on the rocks are because of different deposition of sediments. Different sediments deposited over the rocks through wind, water and ice over the ages
Explanation: