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2 years ago

How might an entire insect be preserved?

Chemistry

2 answers:

kirill [66]2 years ago

8 0

Answer:

The correct answer is "Tree sap flows over the insect and hardens".

Explanation:

The tree sap, amber in color, flows over the insects and preserves them, conserving them in such a way that part of their cellular structure and even fragments of their DNA can be found intact. The resin, draining over the bark of trunks and branches, managed to trap insects as it hardened over time, becoming amber. The hardened amber stone can preserve the softest parts of any insect, keeping it completely intact over time.

Have a nice day!

topjm [15]2 years ago

4 0

Tree sap flows over the insect and hardens

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What is the emf produced in a 1.5 meter wire moving at a speed of 6.2 meters/second perpendicular to a magnetic field of strengt

valentinak56 [21]

Answer:

0.037 volts

Explanation:

5 0

2 years ago

Which of the following compounds has polar covalent bonds: NaBr, Br2, HBr, and CBr4?

svetlana [45]

Answer: Option (e) is the correct answer.

Explanation:

A bond that is formed when an electron is transferred from one atom to another results in the formation of an ionic bond.

For example, NaBr will be an ionic compound as there is transfer of electron from Na to Br.

Whereas a bond that is formed by sharing of electrons is known as a covalent bond.

For example, $CBr_{4}$ will be a covalent compound as there is sharing of electron between carbon and bromine atom.

Also, when electrons are shared between the combining atoms and there is large difference in electronegativity of these atoms then partial charges develop on these atoms. As a result, it forms a polar covalent bond.

For example, in a HBr compound there is sharing of electrons between H and Br. Also, due to difference in electronegativity there will be partial positive charge on H and partial negative charge on Br.

Thus, we can conclude that out of the given options HBr is the only compound that has polar covalent bonds.

8 0

2 years ago

A 60.0 mL solution of 0.112 M sulfurous acid (H2SO3) is titrated with 0.112 M NaOH. The pKa values of sulfurous acid are 1.857 (

djverab [1.8K]

Answer:

a)4.51

b) 9.96

Explanation:

Given:

NaOH = 0.112M

H2S03 = 0.112 M

V = 60 ml

H2S03 pKa1= 1.857

pKa2 = 7.172

a) to calculate pH at first equivalence point, we calculate the pH between pKa1 and pKa2 as it is in between.

Therefore, the half points will also be the middle point.

Solving, we have:

pH = (½)* pKa1 + pKa2

pH = (½) * (1.857 + 7.172)

= 4.51

Thus, pH at first equivalence point is 4.51

b) pH at second equivalence point:

We already know there is a presence of SO3-2, and it ionizes to form

SO3-2 + H2O <>HSO3- + OH-

$Kb = \frac{[ HSO3-][0H-]}{SO3-2}$

$Kb = \frac{10^-^1^4}{10^-^7^.^1^7^2} = 1.49*10^-^7$

[HSO3-] = x = [OH-]

mmol of SO3-2 = MV

= 0.112 * 60 = 6.72

We need to find the V of NaOh,

V of NaOh = (2 * mmol)/M

= (2 * 6.72)/0.122

= 120ml

For total V in equivalence point, we have:

60ml + 120ml = 180ml

[S03-2] = 6.72/120

= 0.056 M

Substituting for values gotten in the equation $Kb=\frac{[HSO3-][OH-]}{[SO3-2]}$

We noe have:

$1.485*10^-^7=\frac{x*x}{(0.056-x)}$

$x = [OH-] = 9.11*10^-^5$

$pOH = -log(OH) = -log(9.11*10^-^5)$

=4.04

pH = 14- pOH

= 14 - 4.04

= 9.96

The pH at second equivalence point is 9.96

4 0

2 years ago

A student adds solid KCl to water in a flask. The flask is sealed with a stopper and thoroughly shaken until no more solid KCl d

AlladinOne [14]

Answer:

Option (A) saturated and is at equilibrium with the solid KCl

Explanation:

A saturated solution is a solution which can not dissolve more solute in the solution.

From the question given above, we can see that the solution is saturated as it can not further dissolve any more KCl as some KCl is still visible in the flask.

Equilibrium is attained in a chemical reaction when there is no observable change in the reaction system with time. Now, observing the question given we can see that there is no change in flask as some KCl is still visible even after thorough shaking. This simply implies that the solution is in equilibrium with the KCl solid as no further dissolution occurs.

4 0

2 years ago

Be sure to answer all parts. There are three different dichloroethylenes (molecular formula C2H2Cl2), which we can designate X,

sertanlavr [38]

Answer:

Explanation:Since the compound X has no net-dipole moment so we can ascertain that this compound is not associated with any polarity.

hence the compound must be overall non-polar. The net dipole moment of compound is zero means that the vector sum of individual dipoles are zero and hence the two individual bond dipoles associated with C-Cl bond must be oriented in the opposite directions with respect to each other.]

So we can propose that compound X must be trans alkene as only in trans compounds the individual bond dipoles cancel each other.

If one isomer of the alkene is trans then the other two isomers may be cis .

Since the two alkenes give the same molecular formula on hydrogenation which means they are quite similar and only slightly different.

The two possibility of cis structures are possible:

in the first way it is possible the one carbon has two chlorine substituents and the carbon has two hydrogens.

Or the other way could be that two chlorine atoms are present on the two carbon atoms in cis manner that is on the same side and two hydrogens are also present on the different carbon atoms in the same manner.

Kindly refer the attachments for the structure of compounds:

7 0

2 years ago