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DIA [1.3K]
3 years ago
15

How did oxygen first enter Earth's atmosphere?

Chemistry
1 answer:
forsale [732]3 years ago
8 0

Answer:

I think c biological processes

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If kb for nx3 is 1.5×10−6, what is the poh of a 0.175 m aqueous solution of nx3?
Charra [1.4K]
Answer is: pOH = 3,29.
Kb(NH₃) = 1,5·10⁻⁶.
c(NH₃) = 0,175M.
pOH = ?
Chemical reaction: NH₃ + H₂O ⇄ NH₄⁺ + OH⁻.
Kb = c(NH₄⁺) · c(OH⁻) ÷ c(NH₃).
c(NH₄⁺) = c(OH⁻) = x.
x² = Kb · c(NH₃) 
x² = 1,5·10⁻⁶ · 0,175 = 2,625 ·10⁻⁷.
x = c(OH⁻) = √2,625 ·10⁻⁷ = 5,12 · 10⁻⁴.
pOH = -log(c(OH⁻)) = 3,29.

3 0
3 years ago
Help me plz A substance found in the solid form at room temperature has
bezimeni [28]

Answer:

Medium

Explanation:

It is known that it can handle room temperture but not known about other tempertures so it best to infer that it is medium.

3 0
3 years ago
Calculate the standard heat of reaction for the following methane-generating reaction of methanogenic bacteria: 4CH3NH2(g) + 2H2
PIT_PIT [208]

<u>Answer:</u> The standard heat for the given reaction is -138.82 kJ

<u>Explanation:</u>

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate enthalpy change is of a reaction is:

\Delta H^o_{rxn}=\sum [n\times \Delta H_f_{(product)}]-\sum [n\times \Delta H_f_{(reactant)}]

For the given chemical reaction:

4CH_3NH_2(g)+2H_2O(l)\rightarrow 3CH_4(g)+CO_2(g)+4NH_3(g)

The equation for the enthalpy change of the above reaction is:

\Delta H_{rxn}=[(3\times \Delta H_f_{(CH_4(g))})+(1\times \Delta H_f_{(CO_2(g))})+(4\times \Delta H_f_{(NH_3(g))})]-[(4\times \Delta H_f_{(CH_3NH_2(g))})+(2\times \Delta H_f_{(H_2O(l))})]

We are given:

\Delta H_f_{(H_2O(l))}=-285.8kJ/mol\\\Delta H_f_{(NH_3(g))}=-46.1kJ/mol\\\Delta H_f_{(CH_4(g))}=-74.8kJ/mol\\\Delta H_f_{(CO_2(g))}=-393.5kJ/mol\\\Delta H_f_{(CH_3NH_2(g))}=-22.97kJ/mol

Putting values in above equation, we get:

\Delta H_{rxn}=[(3\times (-74.8))+(1\times (-393.5))+(4\times (-46.1))]-[(4\times (-22.97))+(2\times (-285.8))]\\\\\Delta H_{rxn}=-138.82kJ

Hence, the standard heat for the given reaction is -138.82 kJ

3 0
3 years ago
PLEASEEEEEEEEEEEEEEEEE HELPPPPPPPPPPPPPPPPPPPPPPPP
Sophie [7]

give a very origin example a student that include B sin displayed

7 0
3 years ago
Can someone help me out with why is the outer core of Earth is important in you’re own words?! A mini paragraph plsss
Helen [10]

Answer:

the outer core is important because the outer core is responsible for earth's magnetic field which protects earth from harmful particles that comes from sun and also contains some natural metal like nikle and iron.

is this much paragraph enough comment down below..

hope this helps you ☺️☺️

6 0
3 years ago
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