Answer:

Explanation:
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In this case, since the standard enthalpy change for a chemical reaction is stood for the enthalpy of reaction, for the given reaction:

We set up the enthalpy of reaction considering the enthalpy of formation of each species in the reaction at the specified phase and the stoichiometric coefficient:

In such a way, by using the NIST database, we find that:

Thus, we plug in the enthalpies of formation to obtain:

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Answer
_2 HNO₃ + 1 Mg(OH)₂ → 1 Mg(NO₃)₂ + 2 H₂O
Explanation
Given:
______HNO3 + Mg(OH)2 ------>
Solution:
Note that the reaction between an acid and a base will give salt and water only.
Hence the complete reaction of the given equation is:
___HNO₃ + Mg(OH)₂ → Mg(NO₃)₂ + H₂O
To get the balanced equation for the acid-base reaction, 2 moles of HNO₃ will react with 1 mole of Mg(OH)₂ to produced 1 mole of Mg(NO₃)₂ and 2 moles of H₂O.
Therefore, the complete and balanced equation for the given acid-base reaction is:
_2 HNO₃ + 1 Mg(OH)₂ → 1 Mg(NO₃)₂ + 2 H₂O
Answer:
19.K, potassium
Explanation:
it has all properties of metals