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3 years ago

What do sedimentary rock layers reveal about ancient environments?

1 answer:

8 0

The most comprehensive story of ancient environment is traced by type of Sedimentary rocks. The different ancient environment forms different kinds of sedimentary rocks in terms of shape, size, pattern of sorting etc.

For example:

an ancient environment of lake will have laminated sedimentary rocks while a deserted one will have cross beds or granules.

Not only this we can also have an idea about the kind of flora and fauna of ancient environment based on the fossils. which may be in the form of architectural features.

So they reveal both kind of life / living organism and the kind of earth like river, desert, lake, swamp, lagoon etc.

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You can choose from four different materials to make the handrails that run up the stairs and around the playhouse: steel, alumi

Oduvanchick [21]

I think it would be minimize so u can have more friction

8 0

3 years ago

Calculate the percent ionic, the percent covalent, and the bond length (in picometers) of a chemical bond between phosphorus and

kirza4 [7]

Answer:

The correct option is;

4 percent ionic, 96 percent covalent, 222 pm

Explanation:

The parameters given are;

Phosphorus:

Atomic radius = 109 pm

Covalent radius = 106 pm

Ionic radius = 212 pm

Electronegativity of phosphorus = 2.19

Selenium:

Atomic radius = 122 pm

Covalent radius = 116 pm

Ionic radius = 198 pm

Electronegativity of selenium= 2.55

The percentage ionic character of the chemical bond between phosphorus and selenium is given by the relation;

Using Pauling's alternative electronegativity difference method, we have;

$\% \, Ionic \ Character = \left [18\times (\bigtriangleup E.N.)^{1.4} \right ] \%$

Where:

Δ E.N. = Change in electronegativity = 2.55 - 2.19 = 0.36

Therefore;

$\% \, Ionic \ Character = \left [18\times (0.36)^{1.4} \right ] \% = 4.3 \%$

Hence the percentage ionic character = 4.3% ≈ 4%

the percentage covalent character = (100 - 4.3)% = 95.7% ≈ 96%

The bond length for the covalent bond is found adding the covalent radii of both atoms as follows;

The bond length for the covalent bond = 106 pm + 116 pm = 222 pm.

The correct option is therefore, 4 percent ionic, 96 percent covalent, 222 pm.

4 0

3 years ago

What is the total number of joules required to completely melt 221 grams of ice?

DiKsa [7]

Answer:

6680

Explanation:

hope it help :)

7 0

3 years ago

Calculate the standard cell potential (E∘) for the reaction X(s)+Y+(aq)→X+(aq)+Y(s) if K = 5.59×10−3.

Blizzard [7]

Answer:

E° = -0.133 V

Explanation:

In the reaction:

X(s) + Y⁺(aq) → X⁺(aq) + Y(s)

1 electron is transferred from X to Y

Now, using Nernst equation:

E° = RT / nF ln K

Where R is gas constant (8.314 J/molK), T is absolute temperature (Usually 298.15K), n are transferred electrons (1, for the reaction), F is faraday constant (96485C/mol) and K is equilibrium constant (5.59x10⁻³)

Replacing:

E° = 8.314 J/molK*298.15K / 96485C/mol*1 ln 5.59x10⁻³

E° = -0.133 V

5 0

3 years ago

Sodium peroxide (Na2O2) is used to remove carbon dioxide from (and add oxygen to) the air supply in spacecrafts. It works by rea

bazaltina [42]

The volume (in liters) of CO₂ that can be consumed at STP by 435 g Na₂O₂ is 125 L of Co₂

calculation

2Na₂O₂(s) +2 CO₂ (g)→ 2 Na₂CO₃(s) + O₂(g)

Step 1 : find the moles of Na₂O₂

moles = mass÷ molar mass

from periodic table the molar mass of Na₂O₂ = (23 x2) +( 16 x2) = 78 g/mol

moles= 435 g÷ 78 g/mol = 5.58 moles

Step 2: use the mole ratio to determine the moles of CO₂

from given equation Na₂O₂ : CO₂ =2 :2 =1:1

Therefore the moles of CO₂ is also = 5.58 moles

Step 3: find the volume of CO₂ at STP

that is at STP 1 mole of a gas = 22.4 L

5.58 moles = ? l

by cross multiplication

= (5.58 moles x 22.4 L) / 1 mole = 125 L

6 0

3 years ago