A man is walking in the park at night when he sees a shadow suddenly dart across his path. Which glands will be responsible for controlling his “fight or flight” reaction? Check all that apply.

adrenal

thymus

pancreas

hypothalamus

Answer:

See explanation

Explanation:

Let us remember that the Iodide ion is a good nucleophile.  SN2 reaction is  promoted in a polar aprotic solvents like  acetone.

Aprotic solvents like acetone do not favor the formation of a carbocation hence the reaction of Sodium iodide in acetone with PhCH2Cl proceeds by SN2 mechanism. This is possible because the compound possesses a halogen atom(Cl) which is easily replaced by I^- from NaI. The corresponding NaCl formed is insoluble in acetone.

Similarly, when AgNO3/ethanol reacts with PhCH2Cl; ethanol which is a polar protic solvent and a poor nucleophile coordinates with the silver ion in the  PhCH2Cl and enhances carbocation formation (SN1 mechanism operates).

The SN2 mechanism is not followed here because there is no good nucleophile present compared to the situation in the reaction of PhCH2Cl with NaI/acetone.

C: Causing rapid algal growth that decreases oxygen levels and chokes aquatic life.

If this is incorrect, please, don't refrain to tell me. Thank you.

When fertilizers enter the water surface they cause brisk algal growth, which reduces the levels of oxygen and choke aquatic life.

It is the phenomenon by which the entire water body, or some part of it becomes enriched with nutrients and minerals, mainly the phosphorus and nitrogen. This generally takes place when the fertilizers used in fields get washed in the water body.

A common effect of eutrophication is algal blooms. The emergence of algal blooms results in the depletion of oxygen of the water body resulting in  the choking of aquatic life.

Thus, the correct answer is option C.

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Answer:

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\ [/tex]

From the question

volume = final volume of water - initial volume of water

volume = 18.3 -15 = 3.3 mL

We have

[tex]density = \frac{33.65}{3.3} \\ = 10.19696969...[/tex]

We have the final answer as

Hope this helps you

Answer:

D. It's the only one with C6H14 on the reactant side.

Explanation:

Answer:

[OH⁻] = 4.0 × 10⁻⁹ M

Acidic

Explanation:

Step 1: Given data

Step 2: Calculate the concentration of OH⁻

We will use the following expression.

[H₃O⁺].[OH⁻] = Kw = 1.0 × 10⁻¹⁴

[OH⁻] = 1.0 × 10⁻¹⁴/[H₃O⁺] = 1.0 × 10⁻¹⁴/2.5 × 10⁻⁶ = 4.0 × 10⁻⁹ M

Step 3: Calculate the pH

We will use the following expression.

pH = -log [H₃O⁺] = -log 2.5 × 10⁻⁶ = 5.6

Since the pH < 7, the solution is acidic.

Answer:

There are two properties that can be used to identify an element: the atomic number or the number of protons in an atom. The number of neutrons and number of electrons are frequently equal to the number of protons, but can vary depending on the atom in question.

Answer:

e. None of these

Explanation:

The oxide of Bromine (BrₐOₓ) produce "a" moles of Br that are equal to "a" moles of AgBr. The moles of AgBr are:

Moles AgBr:

3.188g AgBr * (1mol / 187.78g) = 0.01698 moles of AgBr = Moles of Br

These moles of Br weighs (Molar mass: 79.9g/mol):

0.01698 moles of Br * (79.9g / mol) = 1.36g of Br

Mass of Oxygen must be:

1.90g - 1.36g Br = 0.54g oxygen. In moles:

0.54g O * (1mol / 16g) = 0.03375 moles of O

Empirical formula is the simplest ratio of atoms in the molecule. Dividing in the moles of Br:

Br:  0.01698 moles of Br / 0.01698 moles = 1

O: 0.03375 moles of O / 0.01698 moles = 1.99 ≅ 2

That means empirical formula is:

BrO₂

And right option is:

The empirical formula of the oxide would be [tex]BrO_2[/tex]

1.90 g of the oxide of bromine produces 3.188 g of AgBr

moles of 3.188 g AgBr = 3.188/187.78

                                        = 0.017 moles

AgBr ---> Ag+ + Br-

Thus, mole of Br in AgBr = 0.017 moles

Mass of 0.017 Br = mole x molar mass

                           = 0.017 x 79.904

                              = 1.357 g

Mass of oxygen in the oxide of bromine = 1.90 - 1.357

                                                                    = 0.543 g

mole of 0.543 oxygen = 0.543/16

                                       = 0.0339 moles

mole of 1.357 g Br = 0.017

Dividing by the smallest:

Br = 0.017/0.017 = 1

O = 0.0339/0.017 = 1.99

Empirical formula = BrO2

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Answer: The volume of 0.300 M NaF required is 59.6 ml

Explanation:

According to the dilution law,

[tex]C_1V_1=C_2V_2[/tex]

where,

[tex]C_1[/tex] = concentration of concentrated NaF solution = 0.300 M

[tex]V_1[/tex] = volume of pure concentrated Na F solution = ?

[tex]C_2[/tex] = concentration of diluted NaF solution= 0.0715 M

[tex]V_2[/tex] = volume of diluted NaF solution= 250.0 ml

[tex]0.300\times x=0.0715\times 250.0[/tex]

[tex]x=59.6ml[/tex]

Thus the volume of 0.300 M NaF required is 59.6 ml

Answer: This means that the isotope of silicon with a mass number of 28 is by far the most common of these three isotopes.

Explanation:

The abundance of Si-28 is 92.23%. Si-29 is 4.68% and Si-30 is 3.09%.

Answer:yes,no,no,yes

The question is incomplete; the complete question is;

Identify the possible issues if a sample in a spectrophotometer gives no reading. Select one or more:

The wrong wavelength may be set.

The sample may be placed improperly in the cuvette holder.

There may be an issue with the composition of the sample.

There may be an issue with the spectrophotometer

Answer:

The wrong wavelength may be set.

There may be an issue with the spectrophotometer

Explanation:

Substances do not absorb radiation at all wavelengths. The proper wavelength at which a substance absorbs must be used for a reading to be obtained from the spectrophotometer. If this is not done, no reading is obtained from the spectrophotometer.

Generally, if the spectrophotometer has an issue, it may display no reading until the machine is fixed.

The possible issues if a sample in a spectrophotometer gives no reading are:

According to the given question, we are asked to identify the possible reasons why a spectrophotometer would give no reading when a sample is used on it.

As a result of this, it is important to note that it is possible that the sample may not have been placed correctly on the cuvette holder or the wrong wavelength may be set which would cause the no reading error to show.

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Answer:

[tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]

Explanation:

Hello.

In this case, since the reaction is not given but a typical precipitation of silver from silver nitrate could be represented by its reaction with a soluble metallic sulfide or carbonate since silver carbonate and silver sulfide are insoluble, we can use for instance sodium carbonate to obtain:

[tex]2AgNO_3(aq)+Na_2CO_3(aq)\rightarrow Ag_2CO_3(s)+2NaNO_3(aq)[/tex]

Thus, since, silver nitrate, sodium carbonate and sodium nitrate are fully ionized by silver carbonate remains solid, the complete ionic equation is:

[tex]2Ag^+(aq)+2NO_3^-(aq)+2Na^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)+2Na^+(aq)+2NO_3^-(aq)[/tex]

Then, since nitrate and sodium ions are the spectator ions since they are at both reactants and products, the net ionic equation turns out:

[tex]2Ag^+(aq)+CO_3^{2-}(aq)\rightarrow Ag_2CO_3(s)[/tex]

Best regards!

Answer:

0.0820M H₃PO₄

Explanation:

THe phosphoric acid, H₃PO₄ reacts with sodium hydroxide, NaOH, thus:

H₃PO₄ + 3NaOH → Na₃PO₄ + 3H₂O

The moles of NaOH used to neutralize the acid are:

Moles NaOH:

20.8mL = 0.0208L * (0.532mol / L) = 0.0111 moles NaOH.

That means moles of phosphoric acid in the solutionare:

0.0111 moles NaOH * (1mole H₃PO₄ / 3 moles NaOH) =

0.00369 moles H₃PO₄

These moles are in 45.0mL = 0.045L. The molar concentration of the solution are:

0.00369 moles H₃PO₄ / 0.045L =

Answer:

Explanation:

abything that is both mass and volume

Answer:

anything that has both mass and volume

Answer:alkali metals have lower ionization energies

Explanation:

----Alkali metals tend to be more reactive than alkaline earth metals because alkali metals have lower ionization energies

Alkali metals are metals found in group 1 and examples are Lithium, Sodium and potassium having 1 electron in their outermost shell, Alkali earth metals on the other hand are found in group 2 of the periodic table  and examp-les of which are  Beryllium, magnesium, Calcium  having 2 electrons in their outermost shells

Alkali metals are more reactive  than the alkali earth metal due to the former having a lower ionization energy  as we know , Ionization energy is the lowest energy it takes to remove a mole of electron from a mole of atom in gaseous sate, We can now see that it will take a very small amount to remove  1 valence electron than two valence electrons  and the ability to easily loose electron makes an element more reactive.

Answer:

Alkali metals tend to be more reactive than alkaline earth metals because-

Explanation:

The more easily an electron is lost, the more reactive it is. Alkalines have 2 valence electron (electrons on the outer shell) whereas, Alkalis have 1 valence electron. So Alkaline's bond is stronger. An increase in density also increases the attraction force between nucleus and electron. Therefore Alkali are more reactive.

Answer:

Taking energy away from a gas cooling it down may cause it to turn into a liquid or condense

Answer:

sold,liquidator gas

Explanation:

pressure| practicelmodel of matter| siyavula

Answer:

1 mole

The first step is to calculate the molar mass (gram formula weight) of MgCl2. Molar mass = (24.31 + 2 × 35.45) = 95.21 g mol–1 i.e. 95.21 g of MgCl2 is exactly 1 mole

Answer:

X and Z

Explanation:

See attachment for complete question...

Your question illustrates kinetic energy as it relates to height (according to the attachment)

Kinetic energy increases with a decrease in height.

So, from the attachment...

W and Y are at higher heights.

While X and Z are at lowest heights

By the analysis above, kinetic energy would be at highest at X and then Z.

Hence, the answer to the question is X and Z.

Answer:

2.25E18

Explanation:

0.000045 g of Carbon x (1 mol C/ 12.01 g C) x (6.02 x 10E23 atoms / 1 mol C)

Start with the mass, then multiply it by the molar mass but put moles on the top and grams on the bottom to cancel out the grams. Then multiply it by Avogadros Constant to get atoms

Answer:

[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s)[/tex]

Explanation:

Hello.

In this case, we can first write the complete molecular equation as shown below:

[tex]CaBr_2(aq)+Na_2CO_3\rightarrow CaCO_3 (s) +2NaBr(aq)[/tex]

In such a way, since all the species but calcium carbonate remain in aqueous solution, they are successfully dissociated whereas the solid product remain undissociated:

[tex]Ca^{2+}(aq)+2Br^-(aq)+2Na^+(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s) +2Na^+(aq)+2Br^-(aq)[/tex]

Thus, we can cancel out bromide and sodium ions as spectator ions, in order to obtain the required net ionic equation:

[tex]Ca^{2+}(aq)+CO_3^{2-}(aq)\rightarrow CaCO_3 (s)[/tex]

Best regards!

Answer:

0 mg

Explanation:

after 24 days all of it would be gone.

Phosphorus only has a 24 day life span.

Answer:

Explanation:

From the given information:

We explained the reaction mechanism of 2,4-pentanedione with hydrazine to yield 3,5-dimethylpyrazole as shown below;

At the initial stage, the carbonyl oxygen gains a proton, increasing the carbonyl carbon's electrophilicity. After that, the carbonyl carbon is being attacked by hydrazine. Then, the process proceeds with the species formed where removal of a proton takes place. Similarly, hydroxyl oxygen gains a proton. After that, the water molecule is being removed, and further rearrangement of an electron occurs at the site of nitrogen in hydrazine.

From species formed, the removal of a proton takes place. Finally, all step is being repeated to yield the final product known as 3,5 - dimethylpyrazole.

Answer:

i feel like it will have an acid smell

GREETINGS!

The system here is chloroplast, so the boundary of the system would be cell cell membrane. Input will be nutrients, output waste and process photosynthesis

HOPE IT HELPS!

Answer:

Why you use deonized water rather than tap water in this experiment? Because deonized water is pure and without contaminants that can affect the result of the experiment.

Explanation:

When using AgNO3 as the test anion, we used distilled or deionized water instead of tap water because deionized water is purer and free of contaminants that could affect the result of the experiment.

Distillation is the process which involves the conversion of a liquid into  water vapour and it condensed back to liquid form. It is the process in which separation of components of a mixture is based on different boiling points.

It is used to separate liquids from nonvolatile solids and also involve in the separation of alcoholic liquors from fermented materials or in the separation of two or more liquids having different boiling points, as in the separation of gasoline, kerosene, and lubricating oil from crude oil.

A plant that performs distillation is called a distillery while the apparatus used to perform distillation is called a still.

Thus, when using AgNO3 as the test anion, we used distilled or deionized water instead of tap water because deionized water is purer and free of contaminants that could affect the result of the experiment.

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Answer:

A, Chlorine, Cl

Explanation:

Answer:

Pour fluorescent dye and phenyl oxalate ester solution into the glass beaker with the hydrogen peroxide. Once the two solutions are combined, a chemical reaction will take place and cause the fluid to glow in the dark.

Answer:

the apple changed color

Explanation:

cause when it changes to brown it means the apple is no longer edible

many fruits with just having contact with the air it may change color like apple