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4 years ago

Chemistry is

Chemistry

1 answer:

bonufazy [111]4 years ago

7 0

Answer B

the study of matter and how matter changes.

hope this helps!

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Lichens are an example of a(n)

Marta_Voda [28]

Lichens are an examples of Symbiosis

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3 years ago

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Which federal agency makes sure federal wildlife laws are followed?

goldfiish [28.3K]

Answer:

us fish and wildlife service

Explanation:

the 2nd choice

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3 years ago

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An industrial synthesis of urea obtains 87.5 kg of urea upon reaction of 68.2 kg of ammonia with excess carbon dioxide. Determin

dolphi86 [110]

Answer:

The theoretical yield of urea = 120.35kg

The percent yield for the reaction = 72.70%

Explanation:

Lets calculate -

The given reaction is -

$2NH_3(aq)+CO_2$ → $CH_4N_2O(aq)+H_2O (l)$

Molar mass of urea $CH_4N_2O$ = 60g/mole

Moles of $NH_3$ = $\frac{62.8kg/mole}{17g/mole}$ (since $Moles=\frac{mass of substance}{mass of one mole}$ )

= 4011.76 moles

Moles of $CO_2$ = $\frac{105kg}{44g/mole}$

= $\frac{105000g}{44g/mole}$

= 2386.36 moles

Theoritically , moles of $NH_3$ required = double the moles of $CO_2$

but , $4011.76$ , the limiting reagent is $NH_3$

Theoritical moles of urea obtained = $\frac{1 mole CH_4N_2O}{2mole NH_3}\times4011.76 mole NH_3$

= $2005.88mole CH_4N_2O$

Mass of 2005.88 mole of $CH_4N_2O$ = $2005.88 mole \times\frac{60g CH_4N_2O}{1mole CH_4N_2O}$

= 120352.8g

$120352.8g\times \frac{1kg}{1000g}$

= 120.35kg

Therefore , theroritical yeild of urea = 120.35kg

Now , Percent yeild = $\frac{87.5kg}{120.35kg}\times100$

72.70%

Thus , the percent yeild for the reaction is 72.70%

8 0

3 years ago

Consider the molecules: scl2, f2, cs2, cf4, and brcl. select the choice where the bonds of the molecules are arranged in order o

elena-s [515]

The polarity of a bond depends on the difference in electronegativities of the atoms involved in bonding. Greater this difference, greater is the polarity

1) In SCl2 we have the S-Cl bond

Electronegativity values: S = 2.5, Cl = 3

Difference = 3.0 -2.5 = 0.5

2) In F2 we have the F-F bond

Electronegativity value: F = 4.0

Difference = 4.0-4.0 = 0

3) In CS2 we have the C-S bond

Electronegativity value: C = 2.5, S = 2.5

Difference = 2.5 -2.5 = 0

4) In CF4 we have the C-F bond

Electronegativity values: C = 2.5, F = 4.0

Difference = 4.0 -2.5 = 1.5

5) In BrCl we have the Br-Cl bond

Electronegativity values: Br = 2.8, Cl = 3

Difference = 3.0 -2.8 = 0.2

Therefore, the increasing order of polarity is

F2 = CS2 < BrCl < SCl2 < CF4

5 0

3 years ago

I need help with this

lys-0071 [83]

Answer:

Fossils are the some traces or portions of the animals or plants, buried and preserved from past in rocks, sediments or ice.

Explanation:

Correct match is as follows-

Mold and cast fossils- An organism is buried in sediment after it dies.The hard part of organism leave behind a empty space imprinted in the rock. Later sediments and minerals fill the space and harden to make the original copy of the organisms.
Carbon film fossils- An organism buried in sediments gets squeezed and heated inside the earth , leaving behind a thin carbon outline of the organism on a rock.
Amber fossil- An organism covered in tree resin or tree sap , which then hardens with the body of the organisms preserved inside.
Ice fossil- An organism dies in a cold place on earth , its body becomes frozen and covered in layers of ice . The hard and soft part of the body may be preserved.

3 0

4 years ago