Answer : The final temperature of the metal block is, 
Explanation :

As we know that,

.................(1)
where,
q = heat absorbed or released
= mass of aluminum = 55 g
= mass of water = 0.48 g
= final temperature = ?
= temperature of aluminum = 
= temperature of water = 
= specific heat of aluminum = 
= specific heat of water= 
Now put all the given values in equation (1), we get
![55g\times 0.900J/g^oC\times (T_{final}-25)^oC=-[0.48g\times 4.184J/g^oC\times (T_{final}-25)^oC]](https://tex.z-dn.net/?f=55g%5Ctimes%200.900J%2Fg%5EoC%5Ctimes%20%28T_%7Bfinal%7D-25%29%5EoC%3D-%5B0.48g%5Ctimes%204.184J%2Fg%5EoC%5Ctimes%20%28T_%7Bfinal%7D-25%29%5EoC%5D)

Thus, the final temperature of the metal block is, 
Answer:
2HClO4(aq) + Ca(OH)2(aq) → Ca(ClO4)2(aq) + 2H2O(l)
Perchloric acid + Calcium hydroxide → Calcium perchlorate + Water.
Explanation:
This is a neutralization reaction where the acid, Perchloric acid reacts completely with an appropriate amount of base, aqueous Calcium hydroxide to produce salt, aqueous Calcium perchlorate and water, liquid H2O only.
During this reaction, the hydrogen ion, H+, from the HClO4 is neutralized by the hydroxide ion, OH-, from the Ca(OH)2 to form the water molecule, H2O.
Thus, it is called a neutralization reaction.
5. 25 x 10⁻⁷mg
Explanation:
This is mass conversion from mg to kg;
The kg is a quantity of mass used to measure the amount of matter in a substance.
Given mass = 5.25 x 10⁻¹³kg
The kilo- is a prefix that denotes 10³
therefore;
1000g = 1kilogram
the milli- is a prefix that denotes 10⁻⁻³
1000mg = 1g
Now that we know this, we can convert:
5.25 x 10⁻¹³kg x
= 5. 25 x 10⁻¹³ x 10⁶mg
= 5. 25 x 10⁻⁷mg
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Conversion brainly.com/question/1548911
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