The salt water is a mixture because the salt and the water can be separated from each other. The dissolution of salt inside water is a physical change. At the same time, the salt water is an electrolyte, because it conducts electricity. The electricity that was pass through the water led to the decomposition of the water; those bubbles that form inside the water represent oxygen gas which is a product of decomposition of water, therefore the electricity that was passed through the salt water has caused chemical change to occur inside the salt water.<span />
Answer:- 64015 J
Solution: There is 4250 mL of water in the calorimeter at 22.55 degree C.
density of water is 1 g per mL.
So, the mass of water =
= 4250 g
Final temperature of water after adding the hot copper bar to it is 26.15 degree C.
So,
for water = 26.15 - 22.55 = 3.60 degree C
Specific heat for water is 4.184 
The heat gained by water is calculated by using the formula:

where, q is the heat energy, m is mass and c is specific heat.
Let's plug in the values in the formula and do the calculations:

q = 64015 J
So, 64015 J of heat is gained by the water.
The correct answer is option 2 and 3.
The two scenarios that illustrate the relationship between pressure and volume as described by Boyle’s law are as follows:
2. The volume of an underwater bubble increases as it rises and the pressure decreases.
3. The pressure increases in an inflated plastic bag when the bag is stepped on.
According to Boyle's law, pressure of a gas is inversely proportional to its volume at constant temperature. This means that pressure rises as the volume increases and vice versa.
Answer:
d. Heat is released from the reaction
Explanation:
A negative enthalpy change indicates that it is an exothermic reaction. Exothermic reactions release heat.
c. A full s subshell is able to shield a newly filled p subshell from the nucleus, making the first electron in a p subshell easy to remove.
Explanation:
From the given options, a full s-sublevel is able to shield a newly filled p-subshell from the nucleus thereby making the first electron in a p-subshell easy to remove is correct.
What is ionization energy?
Ionization energy is a measure of the readiness of an atom to lose an electron.
First ionization energy is the energy required to remove the most loosely held electron in the gas phase.
The size of an atom/element depends on the number of electrons it contains. The more the electrons, the larger its size.
- The larger an atom becomes the lesser the ionization energy needed to remove the first electron from its outermost shell.
Electron - electron repulsion occurs when two electrons in the same sub-level repels one another.
Shielding effect is the ability of the inner electrons to protect the outer electrons from the pull of the nuclear charge.
In option C, a s-subshell has a greater shielding effect than the p,d and f sub-shell in that order.
A newly introduced electron in the p-sublevel will be loosely held and easier to remove.
Learn more:
First ionization energy brainly.com/question/2153804
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