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Tju [1.3M]
3 years ago
5

Are the following statements true or false? (a) Formal charges represent an actual separation of charges. true false (b) ΔH o rx

n can be estimated from the bond enthalpies of reactants and products. true false (c) All second-period elements obey the octet rule in their compounds. true false (d) The resonance structures of a molecule can be separated from one another in the laboratory. true false
Chemistry
1 answer:
katrin [286]3 years ago
3 0

Answer:

Explanation:

A) Formal charges represent an actual separation of charges.(FALSE)

(B) ΔHo rxn can be estimated from the bond enthalpies of reactants and products.(TRUE)

C)All second-period elements obey the octet rule in their compounds(FALSE).

(D)The resonance structures of a molecule can be separated from one another in the laboratory.(FALSE)

Bond enthalpy which is also reffered to as bond energy is the amount of energy that is required to break one mole of a bond.

taking the single bond between Oxygen and Hydrogen into considerationthe bond energy between their single bond is 463 kJ/mol.

formal charge is used for the comparison of the number of electrons present around an atom in a particular molecule with the number of electrons present around a neutral

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Answer:

22.7 g of CaCl₂ are produced in the reaction

Explanation:

This is the reaction:

CaCO₃ +  2HCl  →  CaCl₂  + CO₂  +  H₂O

Now, let's determine the limiting reactant.

Let's divide the mass between the molar mass, to find out moles of each reactant.

29 g / 100.08 g/m = 0.289 of carbonate

15 g / 36.45 g/m = 0.411 of acid

1 mol of carbonate must react with 2 moles of acid

0.289 moles of carbonate will react with the double of moles (0.578)

I only have 0.411 of HCl, so the acid is the limiting reactant.

Ratio is 2:1, so I will produce the half of moles, of salt.

0.411 / 2 = 0.205 moles of CaCl₂

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A 0.199 M weak acid solution has a pH of 3.99. Find Ka for the acid.
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Answer:

Ka = ( About ) 5 x 10^ - 8

Explanation:

Let us first identify the dissociation equation for this weak acid,

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Knowing this, we can tell what the equilibrium expression is, respectively,

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_________________________________________________

Now let us use the given pH 3.99 to calculate [ H+ ], knowing that pH = −log [H+],

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Substitute known values into the equilibrium expression,

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Ka = ( About ) 5 x 10^ - 8

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Answer:

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