3Mg^3(PO^4)^2 ——— how many atoms are there
1 answer:
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Answer:
Mg = 2,5 g; Al = 5,3 g
Explanation:
1) Reactions
Mg + 2HCl ⟶ MgCl₂ + H₂
2Al + 6HCl ⟶ 2AlCl₃ + 3H₂
2) Mass of each metal
If there had been no reaction, the mass of the solution would have increased by 7,8 g.
The mass increased by only 7,0 g.
The missing 0,8 g must represent the mass of the hydrogen generated by the reaction.
We have two relations:
Mass of Mg + mass of Al = 7,8 g
H₂ from Mg + H₂ from Al = 0,8 g
i) Calculate the moles of H₂
(ii) Solve the relationship
Let x = mass of Mg. Then
7,8 - x = mass of Al
Moles of Mg = x/24.30
Moles of Al = (7,8 - x)/26.98
Moles of H₂ from Mg = (1/1) × moles of Mg = 1 × (x/24,30) = 0,0412x
Moles of H₂ from Al = (3/2) × Moles of Al = 1.5(7,8 - x)/26,98 = (11,7 -1,5x)/26,98
Mass of Mg = 2,5 g
Mass of Al = 7,8 g - 2,5 g = 5,3 g
The masses of the metals are Mg = 2,5 g; Al = 5,3 g
4.743 x s-1 is the value of the rate constant.
The Arrhenius equation describes the relationship between the rate of reaction and temperature for many physical and chemical reactions.
As per Arrhenius equation,
k = Ae-Ea÷RT
T = 227 = 500.15 K
R = 0.008314 kJ/K mol
Ea = 150 kJ/mol
Ea÷RT
= 150÷(0.008314 x 500.15)
= 36.073
k = Ae-36.073 = (2.2 x s-1) (2.156 x
)
k = 4.743 x s-1
So, the correct answer is option d) i.e. 4.7 x s-1
As per Arrhenius equation,
k = Ae-Ea/RT
T = 227 = 500.15 K
R = 0.008314 kJ/K mol
Ea = 150 kJ/mol
Ea÷RT = 150÷(0.008314 x 500.15) = 36.073
k = Ae-36.073 = (2.2 x s-1)(2.156 x
)
k = 4.743 x s-1
Hence, 4.743 x s-1 is the value of the rate constant.
Learn more about the Arrhenius equation here:
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