A. Phase changing. When phase changes nothing chemically changes about the substance, its still the same thing.
Answer : The reaction is endothermic.
Explanation :
Formula used :

where,
= change in temperature = 
Q = heat involved in the dissolution of KCl = ?
m = mass = 0.500 + 50.0 = 50.5 g
c = specific heat of resulting solution = 
Now put all the given value in the above formula, we get:


The heat involved in the dissolution of KCl is positive that means as the change in temperature decreases then the reaction is endothermic and as the change in temperature increases then the reaction is exothermic.
Hence, the reaction is endothermic.
Answer:
boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At)
Explanation:
metalloids are elements that are in between the metals and nonmetals. they are in between because they have properties of both metals and nonmetals.
you can search "metalloids on the periodic table" and go to images to see what i mean :)
A substance can dissolve in another when they have thee same type of intermolecular interaction.
<h3>What is solubility?</h3>
The term solubility of a solute refers to the extent to which a solute dissolve in a solvent. We must know that a substance can dissolve in another when they have thee same type of intermolecular interaction.
Thus;
a) Octane (C8H18) mixes well with CCl4 because they are both non polar substances.
b) Methanol (CH3OH) is mixed with water in all ratios because the both are polar substances.
c) NaBr dissolves very poorly in acetone (CH3 ― CO ― CH3) because acetone is only slightly polar.
Learn more about solubility:brainly.com/question/8591226
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