Answer: When coal is burned, chemical potential energy is transformed into thermal energy, light energy, and sound energy. Only the thermal energy is used for electricity production. Light and sound energy dissipate into the environment, immediately reducing efficiency.
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Answer: acid dissociation constant Ka= 2.00×10^-7
Explanation:
For the reaction
HA + H20. ----> H3O+ A-
Initially: C. 0. 0
After : C-Cx. Cx. Cx
Ka= [H3O+][A-]/[HA]
Ka= Cx × Cx/C-Cx
Ka= C²X²/C(1-x)
Ka= Cx²/1-x
Where x is degree of dissociation = 0.1% = 0.001 and c is the concentration =0.2
Ka= 0.2(0.001²)/(1-0.001)
Ka= 2.00×10^-7
Therefore the dissociation constant is
2.00×10^-7
Answer:
40.8g of sodium sulfate must be added
Explanation:
The reaction of barium nitrate, Ba(NO₃)₂ with sodium sulfate, Na₂SO₄ is:
Ba(NO₃)₂ + Na₂SO₄ → 2 NaNO₃ + BaSO₄(s)
That means, for a complete reaction of an amount of barium nitrate you must add the same amount in moles of sodium sulfate. To solve this problem we need to convert the mass of barium nitrate to moles = Moles of sodium sulfate that must be added:
<em>Moles Ba(NO₃)₂ -Molar mass: 261.3g/mol-:</em>
75g * (1mol / 261.3g) = 0.287 moles = Moles Na₂SO₄
<em>Mass Na₂SO₄ -Molar mass: 142.04g/mol-:</em>
0.287 moles * (142.04g / mol) =
<h3>40.8g of sodium sulfate must be added</h3>
Answer:
Using cobalt glass could be helpful to identify elements that weakly emit blue and/or violet.
Explanation:
1) Chemical equation
<span>2NH4Cl(s)+Ba(OH)2⋅8H2O(s)→2NH3(aq)+BaCl2(aq)+10H2O(l)
2) Stoichiometric ratios
2 mol NH4Cl(s) : 54.8 KJ
3) Convert 24.7 g of NH4Cl into number of moles, using the molar mass
molar mass of NH4Cl = 14 g/mol + 4*1 g/mol + 35.5 g/mol = 53.5 g/mol
number of moles = mass in grams / molar mass
number of moles = 24.7 g / 53.5 g/mol = 0.462 moles
4) Use proportions:
2 moles NH4Cl / 54.8 kJ = 0.462 moles / x
=> x = 0.462 moles * 54.8 kJ / 2 moles = 12.7 kJ
Answer: 12.7 kJ
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