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e-lub [12.9K]
3 years ago
9

Please can u help me .

Chemistry
2 answers:
Marysya12 [62]3 years ago
7 0

Answer:

4 is D 5 is A

Explanation:

sdas [7]3 years ago
4 0

QUESTIONS !

  • 1. Why might pesticides sprayed onto the fields reduce a bean crop?

A Pesticides damage plant leaves.

B Pesticides damage plant roots.

C Pesticides kill insects that feed on bean plants.

D Pesticides kill insects that pollinate bean plants.

  • 2. What may cause the rapid growth of plants in a lake?

A excess fertilizers

B excess herbicides

C low water pH

D low water temperature

ANSWER !

  • 1. (D) Pesticides kill insects that pollinate bean plants.
  • 2. (B) Excess Herbicides

EXPLANATION !

  • 1. When a field is sprayed with a pesticide, not all of the insects will die, and the ones that remain will produce offspring that will also be tolerant to the spray. This forces farmers to use more and different kinds of pesticides, so they can kill all of the insects that might destroy their crop.
  • 2. During periods of heavy rainfall, increased runoff brings more nutrients into a lake. These additional nutrients may be released from flooded soils or carried into the lake on silt or clay particles. Excess nutrients often boost plant growth, particularly algae or free-floating aquatic plants.                       <em>PLEASE MARK AS BRAINLIEST !!!!</em>
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A 1.26 m aqueous solution of an ionic compound with the formula mx2 has a boiling point of 101.63 ∘c. part a calculate the van't
12345 [234]

<span>Answer is: Van't Hoff factor (i) for this solution is 1.051 .
Change in boiling point from pure solvent to solution: ΔT =i · Kb · b.
Kb - </span><span>molal boiling point elevation constant</span><span> is 0.512°C/m.
b -  molality, moles of solute per kilogram of solvent.
b = 1.26 m.
ΔT = 101.63°C - 100</span>°C = 1.63°C.

i = 1.63°C ÷ (0.512°C/m · 1.26 m).

i = 1.051.

5 0
3 years ago
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In a study of the formation of NOx air pollution, a chamber heated to 2200°C was filled with air (0.790 atm N₂, 0.210 atm O₂). W
Irina-Kira [14]

Answer:

N₂ = 0.7515atm

O₂ = 0.1715atm

NO = 0.0770atm

Explanation:

For the reaction:

N₂(g) + O₂(g) ⇄ 2NO(g)

Where Kp is defined as:

Kp = \frac{P_{NO}^2}{P_{N_2}P_{O_2}}}

Pressures in equilibrium are:

N₂ = 0.790atm - X

O₂ = 0.210atm - X

NO = 2X

Replacing in Kp:

0.0460 = [2X]² / [0.790atm - X] [0.210atm - X]

0.0460 = 4X² / 0.1659 - X + X²

0.0460X² - 0.0460X + 7.6314x10⁻³ = 4X²

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Solving for X:

X = - 0.050 → False answer. There is no negative concentrations.

X = <em>0.0385 atm</em> → Right answer.

Replacing for pressures in equilibrium:

N₂ = 0.790atm - X = <em>0.7515atm</em>

O₂ = 0.210atm - X = <em>0.1715atm</em>

NO = 2X = <em>0.0770atm</em>

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4 years ago
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For the gas phase decomposition of t-butyl propionate,C2H5COOC(CH3)3 (CH3)2C=CH2 + C2H5COOHthe rate constant at 540 K is 8.90×10
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Answer:

The activation energy is 164.02 kJ/mol

Explanation:

Log (k2/k1) = Ea/2.303R × [1/T1 - 1/T2]

k1 = 8.9×10^-4 s^-1

k2 = 9.83×10^-3 s^-1

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T1 = 540 K

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Log (9.83×10^-3/8.9×10^-4) = Ea/2.303×8.314 × [1/540 - 1/578]

1.043 = 6.359×10^-6Ea

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