MgCl2
————not sure with the answer
Answer:
The system gains 126100 J
Explanation:
The heat can be calculated by the equation:
Q = nxCxΔT, where Q is the heat, C is the heat capacity,n is the number of moles and ΔT is the variation of temperature (final - initial). The number of moles is the mass divided by the molar mass, so:
n = 250/4 = 62.5 mol.
The system must be in thermal equilibrium with the surroundings, so if the temperature of the surroundings decreased 97 K, the temperature of the system increased by 97 K, so ΔT = 97 K
Q = 62.5x20.8x97
Q = 126100 J
Whenever new evidence is discovered we must make changes in order to adapt theories to the current base of knowledge. If we were to simply never change any scientific theory, then they would likely no longer stand as factual credible pieces of information in the future.
It's 2) a positively-charged nucleus is surrounded by mostly empty space (aka Rutherford's Model).
Most of the atom's mass is inside the nucleus (which contains protons [+] and neutrons [0 charge]), while the electrons [-] "float" around the nucleus like clouds. This is why it's said that the atom is 'mostly empty space'.
