Answer:
Number of atoms = 5.1345 x 10²³
Explanation:
Given:
Mass of sodium = 19.6
Find:
Number of atoms
Computation:
We know that atomic mass of sodium is 22.98
So,
Number of atoms = [Mass of sodium/atomic mass of sodium]Avogadro's number
Number of atoms = [19.6 / 22.98]6.02 x 10²³
Number of atoms = 5.1345 x 10²³
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Answer:
The ice will not melt, and the temperature will remain at 0°C.
Explanation:
The reaction of the sodium in water is exothermic because heat is being released. In an isolated system, the change in heat must be 0, so the released heat must be absorbed by the ice.
The molar mass of Na is 23 g/mol, so the number of moles that reacted was:
n = 0.250 g/ 23g/mol
n = 0.011 mol
By the reaction:
2 moles ------- -368 kJ
0.011 mol ----- x
By a simple direct three rule:
2x = -4.048
x = -2.024 kJ/mol
So the ice will absorbs 2.024 kJ/mol, which is less than the necessary to melt it (6.02 kJ/mol). Then, the ice will not melt.
The temperature of a pure substance didn't change until all of it has changed of phase, so the temperature must remain at 0°C.
Calories heat added = Mass of glass times temp. increase times specific heat of glass
calories (small calories) = l.0 g x 20 degrees x .16 calories/gm/degree C = 3.2 calories
A) Salt, because salt can easily dissolve in water. Oil would not dissolve or evaporate in water (think of an oil spill - does that oil dissappear?). Aluminum foil would definitely not dissolve in water, so it is not soluble.
Answer:
the rise and fall is the tides.
