Answer:
Magnesium and calcium belong to the second group i. e. alkaline earth metals. They are known as earth metals because they are extracted from the earth. They are very reactive elements. Their reactivity increases when we go from top to bottom because the outermost electrons goes farther from the nucleus i. e. atomic radius increases so less energy is needed for its removal.
Answer:
ΔH rx = -43.5 kJ / mol
Explanation:
In water, Xdissolves thus:
X(s) + H₂O(l) → X(aq) + H₂O(aq)
It is possible to find the heat in dissolution process using coffee cup calorimeter equation:
Q = -m×C×ΔT
<em>Where Q is heat, m is mass of solution (35.0g -density 1g/mL- + 2.20g = 37.2g), C is specific heat of solution (4.18J/g°C), and ΔT is change in temperature (26.0°C-15.0°C = 11.0°C)</em>
Replacing:
Q = -37.2g×4.18J/g°C×11.0°C
Q = -1710J = -<em>1.71kJ</em>
As enthalpy is the change in heat per mole of reaction, moles of X that reacted were:
2.20g X × (1mol / 56.0g) = <em>0.0393 moles</em>
As heat produced per 0.0393moles was -1.71kJ, heat per mole of X is:
-1.71kJ / 0.0393mol = -<em>43.5 kJ / mol = ΔH rx</em>
We write the following substances' chemical formula as follows:
Ferric hydrogen sulphate = Fe(HSO4)3.<span>
Tungsten (V) peroxide = </span>W2(O2)5<span>
Nitric acid = HNO3
Aluminum acetate = </span>C6H9AlO6
Hope this answers the question. Have a nice day.
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Answer:
-20 kcal/mol
Explanation:
In a reaction, enzymes reduces the energy of activation, but they have no effect on the Gibb's free energy of reaction. The free energy of the product is the same as it would be without the enzyme. Thus, the enzyme does not affect the free energy of the reaction. Mathematically
Gibb free energy = Enthalpy - temperature x change in entropy
Note that from the relation above, enzyme is not a factor nor is activation energy a factor.
