Answer:Na
Explanation:its not in group 3 to 13 hope this helps god bless
69. The student's skin was obviously warmer than the initial temperature of the bracelet. According to the second law of thermodynamics, heat transfers from a higher temperature to a lower temperature hence heat transfers from the student's skin to the bracelet warming up the bracelet.
70. moles of copper=mass of copper/molar mass of copper
=30.1g/(63.55g/mol)= 0.4736 moles Cu
71. Delta H( heat released) = mCp(deltaT) = 30.1g(0.385 J/gK)(33-19)K = 162.23J
72. Copper is chemically less active than iron.
I don't know if it is organized by reactivity
it is organized by families
it is organized by atomic number
it is NOT organized by atomic mass
it is organized by periods and groups
Answer:
Option B, Because of the reversible nature of crystallizing and dissolving
Explanation:
Solution containing the maximum amount of solute that can be dissolved in the given solvent at the particular temperature is called saturated solution.
Reversible reaction is the reaction which can go in reverse and forward direction both on varying reaction condition.
In the saturated NaCl solution, on lowering temperature, The the dissolved NaCl molecules may crystallize. Likewise on increasing temperature, the crystallized crystals may dissolved. As the reaction moves in both the direction, therefore its considered to be equilibrium system.
Therefore, amog given, option B is correct.
Because of the reversible nature of crystallizing and dissolving
