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aleksandr82 [10.1K]
3 years ago
10

A woolly mammoth was found in 1999 buried in the frozen soil of the Siberian tundra. Carbon-14 dating indicated that it had died

about 20,000 years ago. Many fossils represent only the partial remains of organisms. However, a complete mammoth with bones, skin, hair, and internal organs intact represented a unique opportunity for scientists to investigate the lifestyle of this animal and the environment in which it lived. The low permeability of the tundra soil helped to preserve the mammoth. Explain why the tundra soil has a low permeability.
Chemistry
1 answer:
klemol [59]3 years ago
7 0

Tundra soils are formed at high latitudes which leaves the tundra always very cold. Tundra soils are generally frozen, and are classifed as Gelisols (this means that permafrost are within 100 cm of the soil surface). These permafrost are as a result of the freezing by winter of the underground water that was accumulated in summer. These soils freeze and thaw alot and as result of that, moisture do not permeate the soil easily. Also, due to this harsh temperature and underground permafrost, most organisms that died in the tundra are preserved within the soil.

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If 8.50 g of phosphorus reacts with hydrogen gas at 2.00 atm in a 10.0-L container at 298 K, calculate the moles of PH3 produced
ahrayia [7]

Answer:

The moles of PH₃ produced are 0.2742 and the total number of moles of gas present at the end of the reaction is 0.6809.

Explanation:

Phosphorus reacts with H₂ according to the balanced equation:

P₄ (s) + 6 H₂ (g) ⇒ 4 PH₃ (g)

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:

  • P₄: 1 mole
  • H₂: 6 moles
  • PH₃:4 moles

Being the molar mass of the compounds:

  • P₄: 124 g/mole
  • H₂: 2 g/mole
  • PH₃: 34 g/mole

The following mass amounts of each compound participate in the reaction:

  • P₄: 1 mole* 124 g/mole= 124 g
  • H₂: 6 mole* 2 g/mole= 12 g
  • PH₃: 4 moles* 34 g/mole= 136 g

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P * V = n * R * T

In this case you know:

  • P= 2 atm
  • V= 10 L
  • n= ?
  • R= 0.082 \frac{atm*L}{mol*K}
  • T= 298 K

Replacing:

2 atm*10 L= n*0.082 \frac{atm*L}{mol*K} *298 K

and solving you get:

n=\frac{2 atm*10 L}{0.082\frac{atm*L}{mol*K}*298 K }

n=0.818 moles

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, you can use a simple rule of three as follows: if 6 moles of H₂ react with 124 g of P₄, 0.818 moles of H₂ with how much mass of P₄ will it react?

mass of P_{4}=\frac{0.818 moles of H_{2}*124 grams of P_{4}}{6 moles of H_{2}}

mass of P₄= 16.90 grams

But 16.90 grams of P₄ are not available, 8.50 grams are available. Since you have less mass than you need to react with 0.818 moles of H₂, phosphorus P₄ will be the limiting reagent.

Then you can apply the following rules of three:

  • If 124 grams of P₄ produce 4 moles of PH₃, 8.50 grams of P₄, how many moles do they produce?

moles of PH_{3} =\frac{8.5 grams of P_{4}*4 moles of PH_{3}  }{124grams of P_{4}}

moles of PH₃=0.2742

  • If 124 grams of P₄ react with 6 moles of H₂, 8.50 grams of P₄ with how many moles of H₂ do they react?

moles of H_{2} =\frac{8.5 grams of P_{4}*6 moles of H_{2}  }{124grams of P_{4}}

moles of H₂= 0.4113

If you have 0.818 moles of H₂, the number of moles of gas H₂ present at the end of the reaction is calculated as:

0.818 - 0.4113= 0.4067

Then the total number of moles of gas present at the end of the reaction will be the sum of the moles of PH₃ gas and H₂ gas that did not react:

0.2742 + 0.4067= 0.6809

Finally, <u><em>the moles of PH₃ produced are 0.2742 and the total number of moles of gas present at the end of the reaction is 0.6809.</em></u>

5 0
3 years ago
We have 1700 Tonnes of Amoniac every day. How many tonnes of 63% Nitrogen soda we can get?
V125BC [204]
There are 3 equations involved in manufacturing Nitric Acid from Ammonia. 

First the ammonia is oxidized:
4NH3 + 5O2 = 4NO + 6H2O

Then for the absorption of the nitrogen oxides.
2NO + O2 = N2O4

Lastly, the N2O4 is further oxidized into Nitric acid.
3N2O4 + 2H2O = 4HNO3 + 2NO

Then run stoichiometry through these equations.
The first equation produces roughly 271,722,938 grams of NO
The second equation produces roughly 416,606,944 grams of N2O4
The last equation produces roughly 380,412,294 grams of HNO3 (nitric acid)

Convert the exact number back into tons, and your answer is: 419.332775 tons.

Rounded, I'm going to say that's 419.33 tons.
Hope this helps! :)

Also, it seems that commercially, Nitric Acid is commonly made by bubbling NO2 into water, rather than using ammonia.
3 0
3 years ago
What coefficients can be used to balance the following equation
zheka24 [161]

The coefficient that can be used to balanced the given equation are 3, 2, 6, 1

<h3>What is a chemical equation? </h3>

Chemical equations are representations of chemical reactions using symbols and formula of the reactants and products.

The reactants are located on the left side while the products are located on the right side.

Reactants —> Products

The balancing of chemical equations follows the law of conservation of matter which states that matter can neither be created nor destroyed during a chemical reaction but can be transferred from one form to another.

<h3>How to balance the equation </h3>

K₂CO₃ + FeCl₃ -> KCl + Fe₂(CO₃)₃

There are 3 atoms of C on the right side and 1 on the left side. It can be balanced by writing 3 before K₂CO₃ as shown below:

3K₂CO₃ + FeCl₃ -> KCl + Fe₂(CO₃)₃

There are 6 atoms of K on the left side and 1 on the right side. it can be balanced by writing 6 before KCl as shown below:

3K₂CO₃ + FeCl₃ -> 6KCl + Fe₂(CO₃)₃

There are 6 atoms of Cl on the right side and 3 on the left. It can be balanced by writing 2 before FeCl₃ as shown below:

3K₂CO₃ + 2FeCl₃ -> 6KCl + Fe₂(CO₃)₃

Now the equation is balanced.

Thus, the coefficients are; 3, 2, 6, 1

Learn more about chemical equation:

brainly.com/question/7181548

#SPJ1

5 0
1 year ago
In a constant‑pressure calorimeter, 70.0 mL of 0.350 M Ba(OH)2 was added to 70.0 mL of 0.700 M HCl. The reaction caused the temp
asambeis [7]

Answer:

ΔH = 57 Kj/mole H₂O

Explanation:

6 0
3 years ago
Read 2 more answers
How many kilograms of chlorine are in 21 kg of CF2Cl2
Alik [6]

21 kg x [(3 x 35.45)/(12.01 + 19.00 + (3 x 35.45))] =  

21 kg x (106.35/137.36) = 16.3 kg of chlorine  

You just multiply the weight of the material by the fraction of chlorine (by weight). The others are done the same way

5 0
3 years ago
Read 2 more answers
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