The 1930s saw natural disasters as well as manmade ones: For most of the decade, people in the Plains states suffered through the worst drought in American history, as well as hundreds of severe dust storms, or "black blizzards," that carried away the soil and made it all but impossible to plant crops.

3 0

3 years ago

If the a of a monoprotic weak acid is 1. 2×10^−6. What is the [H] of a 0. 31 m solution of this acid?

Vanyuwa [196]

The pH of the solution of the given acid is 3.099

Let HX be the weak acid:

HX ⇌ $H^{+}$ + $X^{-}$

For which:

$K_{a}$ = [ $H^{+}$ ][ $X^{-}$ ] / [HX]

If $K_{a}$ lies in the range $10^{-4} - 10^{-10}$ we can assume that the equilibrium concentrations used in the expression are a good enough approximation to the initial concentrations.

Rearranging and taking negative logs of both sides gives:

pH = $\frac{1}{2} [pK_{a} - loga]$

a is the concentration of the acid.

$pK_{a} =-logK_{a}$ = -log (2× $10^{-6}$ ) = 5.69

pH = $\frac{1}{2} [5.69- (-0.508)]$

pH = 3.099

Learn more about pH of acid here;

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3 0

2 years ago

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecul

aliya0001 [1]

The question is incomplete as it does not have the options which are:

A) photosystem II

B) photosystem I

C) cyclic electron flow

D) linear electron flow

E) chlorophyll

Answer:Cyclic electron flow

Explanation:

The plants produce ATP molecule by the process of a light-dependent phase of photosynthesis which produces ATP and NADPH molecules.

The ATP and NADPH are produced by the non-cyclic flow of electrons called Z-scheme but when the plant needs extra ATP molecules, they produce more ATP by the cyclic electron flow.

The cyclic electron flow begins when the P₇₀₀ activates electron which then transferred to ferredoxin and then to cyt b₆f and then to plastocyanin. This is repeated and produce ATP molecules escaping the production of NADPH.

Thus, Cyclic electron flow is correct.

4 0

3 years ago

n the formation of chloromethane and hydrogen chloride. The overall reaction is 2CH4(g)+3Cl2(g)⟶2CH3Cl(g)+2HCl(g)+2Cl−(g) 2CH4(g

IrinaVladis [17]

Answer:

The total pressure in the flask is 0,619 atm.

Explanation:

For the reaction:

2CH₄(g) + 3Cl₂(g) ⟶ 2 CH₃Cl(g) + 2HCl(g) + 2Cl⁻(g)

The moles of CH₄ in 295 mL at STP are:

n = PV/RT

Where P is pressure (1 atm), V is volume (0,295L), R is gas constant (0,082atmL/molK) and T is temperature (273,15 K)

Replacing, moles of CH₄ are 0,0132 moles

In the same way, moles of chlorine are 0,0324 moles

As 3 moles of Cl₂ react with 2 moles of CH₄, for a total reaction of 0,0132 moles of CH₄ you need:

0,0132 moles CH₄ × $\frac{3 moles Cl_{2}}{2 moles CH_{4}}$ = 0,0198 moles Cl₂. That means that 0,0324-0,0198 = 0,0126 moles of Cl₂ are in excess.

As the reaction reaches in 77%, the moles of CH₄ that don't react are:

0,0132×(100%-77%)= 3,036x10⁻³ moles of CH₄

Also, the moles of Cl₂ that don't react are:

0,0126 + 0,0198×(100%-77%)= 0,0172 moles of Cl₂

The moles produced of each compound are:

0,0132×77% × $\frac{2 moles CH_{3}Cl}{2 moles CH_{4}}$ = 0,0102 moles of CH₃Cl -that are the same moles of HCl and Cl⁻-

Thus, total moles in the flask are:

3,036x10⁻³ moles of CH₄ + 0,0172 moles of Cl₂ + 0,0102 moles of CH₃Cl + 0,0102 moles of HCl + 0,0102 moles of Cl⁻ = 0,0507 total moles

As the volume of the flask is 2,00L and the final temperature is 298 K. The total pressure in the flask is:

P = nRT/V

P = 0,619 atm

I hope it helps!

3 0

4 years ago