What is a crack in Earths crust along which eathquakes occur??

9

marishachu [46]

Answer:

B. as a food preservative in the manufacture of detergents

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8 0

2 years ago

In the article, Invasion of the Periodical Cicadas, why do scienctists believe that cicadas only reproduce every 13 or 17 years?

frez [133]

Hi, you've asked an incomplete question. However, I assumed you are referring to the article found on the Scientific American website.

Explanation:

<em>Remember,</em> according to that article we are told that scientists notice that these insects have a long nymphal (immature form before becoming adults) stage, one that can last up to 13 to 17 years on the ground before they leave the ground looking for mating partners.

Because it is only after mating occurs at this point that their eggs are laid, that is why scientists believe that cicadas only reproduce every 13 or 17 years.

8 0

2 years ago

Determine whether the given compound name or formula contains a polyatomic ion. N H 4 C l Choose... Magnesium sulfate Choose...

Morgarella [4.7K]

Answer:

NH₄Cl, Magnesium sulfate, KCN

Explanation:

Determine whether the given compound name or formula contains a polyatomic ion.

NH₄Cl. YES. It contains the polyatomic ion ammonium NH₄⁺.

Magnesium sulfate. YES. It contains the polyatomic ion sulfate SO₄²⁻.

Sodium phosphide Na₃P. NO.

SO₃. NO.

Calcium hydroxide Ca(OH)₂. NO.

KCN. YES. It contains the polyatomic ion cyanide CN⁻.

4 0

2 years ago

0.250 moles of NaCl is dissolved in 0.850 L of solution. What is the molar concentration?

Nuetrik [128]

Considering the definition of molarity, the molar concentration is 0.294 $\frac{moles}{liter}$ .

Molarity reflects the concentration of a solution indicating the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:

$molarity=\frac{amount of moles of solute}{volume}$

Molarity is expressed in units $\frac{moles}{liter}$ .

In this case, you know:

amount of moles of solute= 0.250 moles
volume= 0.850 L

Replacing in the definition of molarity:

$molarity=\frac{0.250 moles}{0.850 L}$

Solving:

molarity= 0.294 $\frac{moles}{liter}$

Finally, the molar concentration is 0.294 $\frac{moles}{liter}$ .

Learn more about molarity with this example: brainly.com/question/15406534?referrer=searchResults

6 0

2 years ago

Draw the resonance structures for the conjugate base of Phenol (C6H6O). In one sentence, explain why phenol (C6H6O) has a pKa of

notsponge [240]

Answer:

The four resonance structures of the phenoxide ion are shown in the image attached

The conjugate base of cyclohexanol has only one resonance contributor, while

the conjugate base of phenol has four resonance contributors.

Explanation:

In organic chemistry, it is known that structures are more stable if they possess more resonance contributors. The greater the number of contributing canonical structures, the more stable the organic specie. Since the phenoxide ion has four contributing canonical structures, it is quite much more stable than cyclohexanol having only one contributing structure to its conjugate base. Hence the PKa(acid dissociation constant) of phenol is lesser than that of cyclohexanol. The conjugate base of phenol is stabilized by resonance.

6 0

3 years ago