1. john needs to create a buffered solution at a ph of 3.5 for his biomedical laboratory

Answer:is increase and more collisions :)

Explanation:

Answer:

Molecular formula for the gas is: C₄H₁₀

Explanation:

Let's propose the Ideal Gases Law to determine the moles of gas, that contains 0.087 g

At STP → 1 atm and 273.15K

1 atm . 0.0336 L = n . 0.082 . 273.15 K

n = (1 atm . 0.0336 L) / (0.082 . 273.15 K)

n = 1.500 × 10⁻³ moles

Molar mass of gas = 0.087 g / 1.500 × 10⁻³ moles = 58 g/m

Now we propose rules of three:

If 0.580 g of gas has ____ 0.480 g of C _____ 0.100 g of C

58 g of gas (1mol) would have:

(58 g . 0.480) / 0.580 = 48 g of C  

(58 g . 0.100) / 0.580 = 10 g of H

 48 g of C / 12 g/mol = 4 mol

 10 g of H / 1g/mol = 10 moles

The molecular formula of the compound is C4H10.

At STP;

P = 1 atm

T = 273 K

V = 33.6 mL or 0.0336 L

R = 0.082 atmLK-1mol-1

n = ?

Hence;

n = PV/RT

n = 1 atm × 0.0336 L/0.082 atmLK-1mol-1 × 273 K

n = 0.0015 moles

Number of moles = mass/molar mass

Molar mass= Mass/Number of moles

Molar mass = 0.087 g/0.0015 moles

Molar mass = 58 g/mol

Mass of carbon = (58 g × 0.480) / 0.580 = 48 g of C  

Mass of hydrogen = (58 g × 0.100) / 0.580 = 10 g of H

Number of moles of carbon = 48 g of C / 12 g/mol = 4 mol

Number of moles of hydrogen = 10 g of H / 1g/mol = 10 moles

Formula of the compound must then be C4H10.

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Explanation:

Before proceeding, let's understand what thermosphere and mesosphere are;

The mesosphere is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere.

The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere.

The meteors make it through the exosphere and thermosphere without much trouble because those layers don't have much air. But when they hit the mesosphere, there are enough gases to cause friction and create heat.

Temperatures in the mesosphere decrease with altitude. Because there are few gas molecules in the mesosphere to absorb the Sun's radiation, the

heat source is the stratosphere below. The mesosphere is extremely cold.

Satellites and the International Space Station orbit the Earth within the thermosphere.

Mesosphere;

- is directly above the stratosphere

- acts as a barrier to meteoroids

- is very cold

Thermosphere;

- reaches out into space

- is where satellites travel

Answer:mesosphere: directly above stratosphere, is very cold, acts as a barrier to meteoroids

Explanation:

Answer:

[tex]0.48~\frac{J}{g~^{\circ}C}[/tex]

Explanation:

In this question, we have to remember the relationship between Q (heat) and the specific heat (Cp) the change in temperature (ΔT), and the mass (m).

[tex]Q=m*Cp*ΔT[/tex]

The next step is to identify what values we have:

[tex]Q~=~1870~J[/tex]

[tex]m~=~85.01~g[/tex]

[tex]ΔT~=~45.2~^{\circ}C[/tex]

[tex]Cp~=~X[/tex]

Now, we can plug the values and solve for "Cp":

[tex]1870~J=~85.01~g~*Cp*45.2~^{\circ}C[/tex]

[tex]Cp=\frac{1870~J}{85.01~g~*45.2~^{\circ}C}[/tex]

[tex]Cp=0.48~\frac{J}{g~^{\circ}C}[/tex]

The unknow metal it has a specific value of [tex]0.48~\frac{J}{g~^{\circ}C}[/tex]

I hope it helps!

Answer:

See figures 1 and 2

Explanation:

In the first part of the problem, we have the electrophilic aromatic substitution (Friedel-crafts reaction) in naphthalene. The first step is the production of the acylium ion by the reaction of acetyl chloride and [tex]AlCl_3[/tex]. Then a double bond attacks the acylium ion to form a new C-C bond. Finally, a hydrogen atom is eliminated and the aromaticity is regenerated in the molecule. (See figure 1)

In the second part of the question, we have to draw the resonance structures in this reaction when benzene is added instead of naphthalene. Where a positive charge is produced in the alpha carbon on the ring. This positive charge, can be moved inside the ring if we move the double bonds and we will have cations on the ortho and para positions. (See figure 2).

Answer:

[tex]H_{comb}=-4406kJ/mol[/tex]

Explanation:

Hello,

In this case, the enthalpy of combustion is understood as the energy released when one mole of fuel, in this case octene, is burned in the presence of oxygen and is computed with the enthalpies of formation of the fuel, carbon dioxide and water as shown below (oxygen is circumvented as it is a pure element):

[tex]H_{comb}=8*\Delta _fH_{CO_2}+5\Delta _fH_{H_2O}-\Delta _fH_{C_8H_{10}}[/tex]

Thus, since we already know the enthalpy of combustion of the fuel, for carbon and water we have -393.5 and -241.8 kJ/mol respectively, thereby, the enthalpy of combustion turns out:

[tex]H_{comb}=8*(-393.5kJ/mol)+5(-241.8kJ/mol)-49.0kJ/mol\\\\H_{comb}=-4406kJ/mol[/tex]

Best regards.

Answer:

[tex]\Delta S=6045.8\frac{J}{K}[/tex]

Explanation:

Hello,

In this case, we can compute the change in the entropy for vaporization processes in term of the enthalpy of vaporization as shown below:

[tex]\Delta S=\frac{m*\Delta H}{T}[/tex]

Whereas the temperature is in Kelvins. In such a way, the entropy results:

[tex]\Delta S=\frac{1.00kg*2256x10^3\frac{J}{kg} }{(100+273.15)K}\\\\\Delta S=6045.8\frac{J}{K}[/tex]

Best regards.

Answer:

pressure is = 54.9802atm

Explanation:

using ideal gas equation

PV=nRT

Answer:

dimethoxy(phenyl)methanol

Explanation:

For this question, we have to remember the mechanism of the Grignard reaction. In this case, phenylmagnesium bromide is our nucleophile, a carbo-anion is produced (step 1). Then this carbo-anion can attack the carbonyl group in the dimethyl carbonate, the double bond is delocalized into the oxygen producing a negative charge (step 2). Finally, with the addition of the hydronium ion ([tex]H_3O^+[/tex]), the anion can be protonated to produce the alcohol (dimethoxy(phenyl)methanol) (step 3).

See figure 1

I hope it helps!

Answer:

A

Explanation:

The products are the stuff on the right side of the arrow (yield sign). In this case that would be C₆H₁₂O₂ + 6O₂.

Answer:

5.56 × 10⁻⁸

Explanation:

Step 1: Given data

Step 2: Calculate the concentration of H⁺

We will use the following expression.

pH = -log [H⁺]

[H⁺] = antilog -pH = antilog -3.99 = 1.02 × 10⁻⁴ M

Step 3: Calculate the acid dissociation constant (Ka)

We will use the following expression.

[tex]Ka = \frac{[H^{+}]^{2} }{Ca} = \frac{(1.02 \times 10^{-4})^{2} }{0.187} = 5.56 \times 10^{-8}[/tex]

Answer:

less becuase that moisture adds weight

Explanation:

Answer:

4 and 6 would work for this

Answer:

[tex]\mathbf{H_2PO^{-}_4}[/tex]  and [tex]\mathbf{HPO^{2-}_4}[/tex] are the amphoteric species.

Explanation:

Phosphorus is a non-metallic element belonging to Group 5 of the Periodic table. As a triprotic acid (i.e an acid that has three dissociable protons that undergo stepwise ionization) . Phosphorus reacts vigorously with hot water to form tetraoxosulphate(V) acid.

i.e

[tex]P_4O_{10(s)} + 6 H_2O_{l} \to4H_3PO_{4(aq)}[/tex]

SO;

As a triprotic acid;

The ionization equations are as follows:

NOTE: Instead of the amphoteric species  to be circle as instructed , due to the fact that we are using the LaTex Editor ; we will just need to let them be in bold format which will differentiate them from the rest.

[tex]H_3PO_{4} \leftrightarrow H^+ + H_2PO^{-}_4[/tex]

[tex]\mathbf{H_2PO^{-}_4} \leftrightarrow H^+ + HPO^{2-}_4[/tex]

[tex]\mathbf{HPO^{2-}_4} \leftrightarrow H^+ + PO^{3-}_4[/tex]

Thus; [tex]\mathbf{H_2PO^{-}_4}[/tex]  and [tex]\mathbf{HPO^{2-}_4}[/tex] are the amphoteric species.

Answer: 1) Endothermic

2) Yes, absorbed.

3) 166.86 kJ will be absorbed.

Explanation:

1) To determine if a reaction is endothermic (heat is absorbed by the system) or exothermic (heat is released by the system), first calculate its change in Enthalpy, which is given by:

ΔH = [tex]H_{products} - H_{reagents}[/tex]

For the reaction 2Fe₂O₃(s) ⇒ 4FeO(s) + O₂(g):

Enthalpy of Reagent (Fe₂O₃(s))

Enthalpy of formation for Fe₂O₃(s) is - 822.2 kJ/mol

The reaction needs 2 mols of the molecule, so:

H = 2(-822.2)

H = - 1644.4

Enthalpy of Products (4FeO(s) + O₂(g))

Enthalpy of formation of O₂ is 0, because it is in its standard state.

Enthalpy of formation of FeO is - 272.04 kJ/mol

The reaction produces 4 mols of iron oxide, so:

H = 4(-272.04)

H = -1088.16

Change in Enthalpy:

ΔH = [tex]H_{products} - H_{reagents}[/tex]

ΔH = - 1088.16 - (-1644.4)

ΔH = + 556.2 kJ/mol

The change in enthalpy is positive, which means that the reaction is absorving heat. Then, the chemical reaction is Endothermic.

2) When Fe₂O₃(s) reacts, heat is absorbed because it is an endothermic reaction.

3) Calculate how many mols there is in 94.2 g of Fe₂O₃(s):

n = [tex]\frac{mass}{molar mass}[/tex]

n = [tex]\frac{94.2}{160}[/tex]

n = 0.6 mols

In the reaction, for 2 mols of Fe₂O₃(s), 556.2 kJ are absorbed. Then:

2 mols --------------- 556.2 kJ

0.6 mols ------------- x

x = [tex]\frac{0.6*556.2}{2}[/tex]

x = 167 kJ

It will be absorbed 167 kJ of energy, when 94.2 g of Fe₂O₃(s) reacts.

Answer:

158.7 g

Its the right answer

Answer:

The density would be larger than the correct value.

Explanation:

First off, the realtionship between denisty and volume is given in the equation below;

Density = Mass / Volume

From this equation, Density is inversely proportional to volume. This means as the volume increases, the density decreases and as the volume decreases the density increases.

Assuming all thing's being normal;

Mass = 2g

Volume = 10ml

Density = 2 / 10 = 0.2 g/ml

Second case scenario;

'your pipet was incorrectly calibrated so that it transferred less than 10.00 mL"

Lets have a value of 8ml for our volume. Mass remains constant.

Density = 2 / 8 = 0.25 g/ml

The density would be larger than the correct value.

Answer: The density would be larger than the correct value.

First off, the relationship between density and volume is given by:

Density = Mass / Volume

From this equation, Density is inversely proportional to volume. This means as the volume increases, the density decreases and as the volume decreases the density increases.

Assuming all thing's being normal;

Mass = 2g

Volume = 10ml

Density = [tex]\frac{2}{10}=0.2[/tex]   g/ml

Second case scenario;

'your pipet was incorrectly calibrated so that it transferred less than 10.00 mL"

Lets have a value of 8ml for our volume. Mass remains constant.

Density = [tex]\frac{2}{8}= 0.25[/tex]  g/ml

The density would be larger than the correct value.

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Explanation:

A metal ion is a type of atom compound that has an electric charge.

Such atoms willingly lose electrons in order to build positive ions called cations. The selected  Ions are :

[tex]1. Mn^2^+\\\ 2. Ca^2^+\\\ 3. Co^2^+\\\ 4. Fe^2^-\\\ 5. K^+[/tex]

Answer:

D2 has 1 neutron

and 1 proton

Answer:

0.133 mol (corrected to 3 sig.fig)

Explanation:

Take the atomic mass of H=1.0, and O=16.0,

no. of moles = mass / molar mass

so no. of moles of H2O produced = 1.2 / (1.0x2+16.0)

= 0.0666666 mol

From the equation, the mole ratio of H2:H2O = 2:2 = 1:1,

meaning every 1 mole of H2 reacted gives out 1 mole of water.

So, the no, of moles of H2 required should equal to the no, of moles of H2O produced, which is also  0.0666666 moles.

mass = no. of moles x molar mass

hence,

mass of H2 required = 0.066666666 x (1.0x2)

= 0.133 mol (corrected to 3 sig.fig)

Answer:

5727 years or 5730 (rounded to match 3 sig figs) whichever one your teacher prefers

Explanation:

First Order decay has a half life formula of Half Life = Ln (2) / k = 0.693/K

Half-life = 0.693/k = 0.693/1.21 x10-4 =  5727 years or 5730 (rounded to match 3 sig figs)

This should be correct because if you google the half-life of 14 C it is ~ 5700 years

Answer:

Option A - When |ΔHsolute| > |ΔHhydration|

Explanation:

A solution is defined as a homogeneous mixture of 2 or more substances that can either be in the gas phase, liquid phase, solid phase.

The enthalpy of solution can either be positive (endothermic) or negative (exothermic).

Now, we know that enthalpy is amount of heat released or absorbed during the dissolving process at constant pressure.

Now, the first step in thus process involves breaking up of the solute. This involves breaking up all the intermolecular forces holding the solute together. This means that the solute molecules are separate from each other and the process is always endothermic because it requires energy to break interaction. Thus;

The enthalpy ΔH1 > 0.

Thus, the enthalpy of the solute has to be greater than the enthalpy of hydration.

An endothermic ΔHsolution occurs when |ΔH solute| < |ΔH hydration|.

A substance dissolves in water when the solute - solvent interaction exceeds the solute - solute solute interaction. The energy required to break the bonds between solutes is the ΔHsolute and the energy released when solute - solvent interaction take place is called the ΔHhydration.

We know that when  |ΔH solute| < |ΔH hydration|, energy is required to break up the solute - solute interaction and  ΔHsolution is endothermic.

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Answer:

See explanation

Explanation:

-) Given the molecules propane (C3H8) and n-butane (C4H10) n-butane has the higher boiling point mainly due to a larger chain of carbons.

In this question, in propane, we have a chain of three carbons. In butane, we have fourth carbons. If we have more carbons we will have more interactions. If we have more interactions we have to give more energy to go from liquid to gas, therefore we will have a higher boiling point.

-) Given the molecules diethyl ether (CH3 CH2OCH2 CH3) and 1-butanol (CH3 CH2CH2 CH2OH) 1-butanol has a higher boiling point mainly due to hydrogen bonding.

In the case of butanol, we have the "OH" group. If we have a hydrogen bond to a heteroatom (O, S, P, or N) we will have the presence of this type of interaction between molecules. If we have more interactions we have to give more energy to go from liquid to gas, therefore we will have a higher boiling point.

I hope it helps!

Answer:

I think it would be the Dead Sea

Explanation:

Because the dead sea is already usually in the warmer temperatures, the boiling point of the water would be lower than the rest.

Answer:

As K >>> 1, the reaction will shift to the products

Explanation:

To know the direction of any reaction you must calculate the equilibrium constant, K. If K is < 1, the reaction will shift to the reactants and if k > 1 the reaction will shift to the products.

With the reactions:

HSO₄⁻ ⇄ SO₄²⁻ + H⁺ Ka = 1.26x10⁻²

And:

NH₄⁺ ⇄ NH₃⁺ + H⁺ Ka = 5.6x10⁻¹⁰

The inverse reaction:

NH₃⁺ + H⁺ ⇄ NH₄⁺ 1/Ka = 1.8x10⁹

The sum of the reactions:

HSO₄⁻ + NH₃⁺ + H⁺ ⇄ NH₄⁺ + SO₄²⁻ + H⁺ K = 1.26x10⁻² ₓ 1.8x10⁹ = 2.3x10⁷

Answer:

[tex]1) NH_{4}IO_{3}\\2) Pb(IO_{3})_{4} \\3) NH_{4}(C_{2}H_{3}O_{2})\\4) Pb(C_{2}H_{3}O_{2})_{4}[/tex]

Explanation:

[tex]1) NH_{4}^{+}IO_{3}^{-} ---> NH_{4}IO_{3}\\2) Pb^{4+}(IO_{3}^{-})_{4} --->Pb(IO_{3})_{4} \\3) NH_{4}^{+}(C_{2}H_{3}O_{2})^{-} ---> NH_{4}(C_{2}H_{3}O_{2})\\4) Pb^{4+}(C_{2}H_{3}O_{2})^{-} _{4} --->Pb(C_{2}H_{3}O_{2})_{4}[/tex]

Answer:

Whenever a system in equilibrium gets disturbed, the adjustment of the system is done in such a manner that the effect of the change gets nullified, this is known as Le Chatelier's Principle. Let us consider that if a reaction present in an equilibrium gets disturbed by changing pressure, concentration, pressure, or other things, then the reaction will move in such a manner so that it can attain the equilibrium again.  

Based on the given question, the equation is:  

HF (aq) + H2O (l) ⇒ H3O+ (aq) + F- (aq)

a) When HCl is added, the dissociation of HCl takes place within the water to give rise to Cl- and H3O+ ions. One can witness an overall enhancement in the H3O+ ions concentration and the shifting of the equilibrium will take place in the backward direction based on the Le-Chatelier's principle. Thus, on adding HCl, the concentration of H3O+ and F- ions decreases, and the concentration of HF increases.  

b) When the addition of a strong electrolyte like KF is done, the dissociation of KF is done into the F- and K+ ions. Thus, with the overall enhancement in the F- ions concentration, the shifting of equilibrium will take place in the backward direction based on the Le-Chatelier's principle. Thus, with the addition of KF, the concentration of H3O+ and F- ions decreases, and HF increases.  

c) With the addition of strong electrolytes like NaCl in the solution, the dissociation of NaCl takes place into the Cl- and Na+ ions. With the addition of NaCl, the equilibrium is not disturbed as the ions exhibit no influence on the given equilibrium reaction. Thus, the concentration of H3O+, HF, and F- ions remains unmodified.  

d) With the addition of KOH, the dissociation of KOH takes place into K+ and OH- ions. Based on Le-Chatelier's principle, the equilibrium will shift in the forward direction as the produced OH- ions will consume the hydronium ions. Therefore, the concentration of H3O+ and F- ions increases, while the concentration of HF decreases.  

e) With the addition of HF, that is, a weak acid, the equilibrium will move in the forward direction to counter the change as the concentration of reactant increases. Therefore, the H3O+ and F- ions decreases, and the concentration of HF increases.  

On adding HCl & KOH to the equilibrium concentration of hydronium ion changes, on adding KF concentration of fluoride ion changes, on adding NaCl no change occur and on adding HF concentration of both ion increases.

According to the equilibrium law whenever any stress is applied at the equilbrium state of chemical reaction, then the equilibrium will move on that direction where the effect of the applied stress will decreases.

Given chemical reaction is:

HF (aq) + H₂O (l) ⇄ H₃O⁺ (aq) + F⁻ (aq)

Hence affect on the equilibrium was discussed above.

To know more about equilibrium law, visit the below link:
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Answer:

Following are the answer to this question:

Explanation:

In the given example of aromatic electrophilic substitution and transforms toluene into p-isopropyl toluene. The group CH3 is also an initiating group o, p-directing (by + Inductive effect). Throughout this scenario, only para-substitution occurs also because O- replaced steric and unpredictable transitional cation procedures.

Please find the attachment of diagram:

Answer:

the nucelolo is not part of the atom

Explanation:

The nucleolus is NOT a part of the atom. The nucleolus has its definition in biology as an element of the cell.

Let's remember that the atom is made up of three fundamental elements that are: electrons, protons and neutrons. Protons and neutrons are found in the nucleus while electrons are orbiting around the nucleus.

Answer:

core

Explanation:

there is no such thing as a core in an atom.

The middle is known as the nucleus

The given question is incomplete as it lacks the appropriate options, however, the options related to this question is as follows:

a)Test a composite material in the lab to see how it can be improved.

b)Look into trends of various diseases and their effects on society.

c)Research available drugs for treating illnesses such as cancer and heart disease, as well as the side effects of these drugs.

d)Make a plan for how to conquer a disease with drugs.

Answer:

The correct answer is - b)Look into trends of various diseases and their effects on society.

Explanation:

The young scientist who wants to focus on creating drugs to treat disease must think and look for the diseases that are needed to be treated at the moment or affecting the population most and how it affects the society and then plan how to do it.

So, the scientist needs to check the trends of various disease and their effect on society for developing understanding which disease needs to be cure first and how it affects.

Thus, the most appropriate answer is - option B.

Answer:

b)Look into trends of various diseases and their effects on society.

Explanation:

ap3x