Answer:
A
Explanation:
The dissolving process depends on the interaction between solute and solvent (solvation) and the breaking up of the intermolecular bond between solutes. The former is exothermic in nature, while the later is endothermic. Energy is released when solute-solvent particles interact. When this energy exceeds the energy required to break intermolecular bonds between the solute particles, dissolution is exothermic.
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
Answer: 
Explanation:
Firstly, we have to find the Molecular mass of potassium oxide (
):
atomic mass: 39 u
atomic mass: 16 u
molecular mass: 
This means that in 1 mole of there are 
and we need to find how many moles there are in 
:
1 mole of ----- of
----- of
This is the quantity of moles in 73.9 g of potassium oxide
Now we can calculate the number of atoms in 73.9 g of potassium oxide by the following relation:
Where:
is the number of atoms in 73.9g of potassium oxide
is the Avogadro's number, which is determined by the number of particles (or atoms) in a mole.
Then:
This is the quantity of atoms in 73.9g of potassium oxide
FORCE is how strongly gravity pulls on an object
MASS measures how much space matter takes up
Hope that helped! Good luck!
Salt water is a solution.
A solution is defined as a mixture where one of the substances dissolves in the other (salt dissolves in water)
You can check this by Googling"difference between mixture and solution", where the first thing that comes up are the words that "an example of a solution is salt water".
