My best try would be d an element
Answer is: an instant ice pack becoming cold, splitting a gas molecule and baking bread.
<span>Endothermic reaction
is chemical reaction that absorbs more energy than it releases.
</span>In ice pack, <span>reaction absorbs heat from the surroundings (endothermic reaction), lowering the surrounding temperature.
For splitting molecule and baking bread we must add energy to break bonds between atoms.</span>
Sodium Sulfate
= Na2(SO4) meaning there are two ions of Na+ in one mole of Sodium Sulfate the M
stands for Molarity, defined as Molarity = (moles of solute)/(Liters of
solution), So if the Na2SO4 solution is 3.65M that means one Liter of has 3.65
moles of Na2SO4, the stoichiometry of Na2SO4 shows that there would be two Na+
ions in solution for every one Na2SO4.
Therefore if
3.65 moles of Na2SO4 was to dissolve, it would produce 7.3 moles of Na+, and
since this is still a theoretical solution, we can assume 1 L of solution.
Finally we find
[Na+] = 2*3.65 = 7.3M
Use the same
logic for parts b and c
