please help. it’s my last question.

[OH⁻]= 2.7 x 10⁻¹³

pH = 1.431

Given

[H3O+] = 3.7x10⁻² M.

Required

the [OH-] and pH

Solution

pH = - log [H⁺]

pH = 2 - log 3.7

pH = 1.431

pOH = 14 - 1.431

pOH = 12.569

pOH = - log [OH⁻]

[OH⁻]= 2.7 x 10⁻¹³

or

[OH-][H3O+]=10⁻¹⁴

[OH-]=10⁻¹⁴ : 3.7 x 10⁻²

[OH-] = 2.7 x 10⁻¹³

Answer:

2.69 * 10^-6 Mol/L

Explanation:

The equation of the reaction is;

Cl2CHCO2CH3 -------------------> Cl2CHCO2H + CH3OH

To convert from ppm concentration to Mol/L, we have

M = ppm/MM * 1000

Where;

M = mol/l

MM= Molar mass

M = 1/142.97 g/mol * 1000 =

M= 6.99 * 10^-6 Mol/L

For first order reaction;

ln[A] = ln[A]o -kt

Given that

[A]o = 6.99 * 10^-6 Mol/L

[A]=??

k= 2.7 x 10-4/sec

t= 30 mins * 60 = 1800 s

ln[A] = ln[6.99 * 10^-6] -   (2.7 x 10-4 * 1800)

ln[A] = -11.87 - 0.486

ln[A] = -12.356

[A] = e^(-12.356)

[A] = 4.3 * 10^-6 Mol/L

Concentration of methanol present after 30 mins= 6.99 * 10^-6 - 4.3 * 10^-6 = 2.69 * 10^-6 Mol/L

Answer:

[tex]8.876\times 10^{18}\ km^2[/tex]

Explanation:

In this problem, we need to convert [tex]8.876 \times 10^{12}\ m^2[/tex] to km².

We know that,

1 km = 1000 m

⇒ 1 km² = 10⁶ m²

So,

[tex]8.876 \times 10^{12}\ m^2=8.876 \times 10^{12}\times 10^6\ km^2\\\\=8.876\times 10^{18}\ km^2[/tex]

So, [tex]8.876 \times 10^{12}\ m^2[/tex] is equal to [tex]8.876\times 10^{18}\ km^2[/tex].

Answer:

Gaseous nitrogen (78% in air) is fixed (by nitrogen fixing bacteria, and during lightning), then absorbed and assimilated by plants in the form of proteins, as well as nucleic acids. ... Nitrogen is returned to soil with excretory materials of animals and dead organisms.

Explanation:

Nitrates (or nitrites) are natural chemicals that are found in the soil, air and water. Nitrates are also used as a food additive to stop the growth of bacteria and to enhance the flavor and color of foodsAmmonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations (NR + 4. ), where one or more hydrogen atoms are replaced by organic groups (indicated by R).an obsessive interest in or feeling about someone or something.

"our fixation with diet and fitness"

Denitrification: the loss or removal of nitrogen or nitrogen compounds specifically : reduction of nitrates or nitrites commonly by bacteria (as in soil) that usually results in the escape of nitrogen into the air

Answer:

This is because molecules in a solid are packed against each other. When a vibration begins, the molecules of a solid immediately collide and the compression wave travels rapidly.

Explanation:

Answer:

Boiling Water

Explanation:

Boiling water is an example of physical change and not and not a chemical change because the water vapor still has the same molecular structure as liquid water.If the bubbles were caused by the decomposition of a molecule into gas then boiling would be a chemical change.

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding

Explanation:

Answer:

water

Explanation:

the salt dissapears and turns

into vapor

Answer:

A solution is made when a solid (which we call a solute) dissolves into a liquid (that we call the solvent) one example of a solution is salt dissolved in water. The salt and water can be separated again by evaporation (the water will evaporate if left in a got place leaving the salt behind. I don't know if that was the answer that you were looking for

Answer:

2812.6 g of H₂SO₄

Explanation:

From the question given above, the following data were obtained:

Mole of H₂SO₄ = 28.7 moles

Mass of H₂SO₄ =?

Next, we shall determine the molar mass of H₂SO₄. This can be obtained as follow:

Molar mass of H₂SO₄ = (1×2) + 32 + (16×4)

= 2 + 32 + 64

= 98 g/mol

Finally, we shall determine the mass of H₂SO₄. This can be obtained as follow:

Mole of H₂SO₄ = 28.7 moles

Molar mass of H₂SO₄ =

Mass of H₂SO₄ =?

Mole = mass / Molar mass

28.7 = Mass of H₂SO₄ / 98

Cross multiply

Mass of H₂SO₄ = 28.7 × 98

Mass of H₂SO₄ = 2812.6 g

Thus, 28.7 mole of H₂SO₄ is equivalent to 2812.6 g of H₂SO₄

Answer:

True

Explanation:

Sound waves traveling through air are indeed longitudinal waves with compressions and rarefactions. As sound passes through air (or any fluid medium), the particles of air do not vibrate in a transverse manner.

Answer:

true

Explanation:

ape x

Answer:

[tex]APF(atomic packing factor)=0.31736[/tex]

Explanation:

From the question we are told that

Density of metal [tex]\rho=11.6 g/cm3[/tex]

Atomic weight of [tex]W=157.6 g/mol[/tex]

Atomic radius of [tex]r= 0.127 nm[/tex]

Lattice parameters=>[tex]x=0.523nm[/tex]  and [tex]y=0.330 nm[/tex]

Generally the equation for atomic packing factor is mathematically given as

[tex]APF(atomic packing factor)=\frac{Spere's\ volume}{unit\ cell\ volume}[/tex]

[tex]APF(atomic packing factor)=\frac{N*VN}{VC}[/tex]

Generally the equation for number of atoms N is mathematically given as

[tex]N=\frac{\rho }{atomic raduis*Avacados constant}[/tex]

[tex]N=\frac{11.6 }{0.127*10^{-9}*6.02214086*10^{23} mol-1}[/tex]

[tex]N=4[/tex]

Therefore APF(atomic packing factor)

[tex]APF(atomic packing factor)=\frac{N*VN}{VC}[/tex]

[tex]APF(atomic packing factor)=\frac{4*\frac{4}{3} \pi (0.127)^3}{(0.523)^2 *0.330}[/tex]

[tex]APF(atomic packing factor)=0.31736[/tex]

Answer:

Measure the volume of water poured into a graduated cylinder, then place the object in the water and remeasure the volume. The difference between the two volume measurements is the volume of the object. Now simply divide the mass by the volume to calculate the density of the object.

Answer:

I think Water is carried to the leaves by xylem.

Answer:

d

Explanation:

Answer:

monosaccharides and glycosidic, I think

Explanation:

Answer:

pasagottt po plss

Explanation:

edi wow

Answer:

See explanation

Explanation:

If we desire to recrystallize the given compound then we must do the following;

1) Add the compound to ethanol and heat the system

2) As the solute dissolves, the solution is allowed to cool

3) The solution may be seeded or the vessel scratched to aid crystallization.

4) The pure crystals are now filtered out, washed and dried.

Remember that recrystallization has to do with dissolving a solute in a solvent in which it is only soluble at high temperature but insoluble at low temperature.

The solvent dissolves the impure solute while pure crystals emerges as the temperature decreases.

Answer:

6.499 g

Explanation:

One part of the aqueous HBr reacted with Zinc Hydroxide following the reaction:

And the remaining HBr reacted with NaOH:

First we calculate how many HBr moles remained after reacting with Zn(OH)₂. That number equals the number of NaOH moles used in the titration:

Now we calculate how many moles of HBr reacted with Zn(OH)₂:

Then we convert those 130.75 mmoles of HBr to the Zn(OH)₂ moles they reacted with:

Finally we convert Zn(OH)₂ moles to grams:

The given question is incomplete. The complete question is:

A reversible reaction is said to have reached equilibrium when which of the following conditions is established?

a. concentration of reactants and products are equal

b. opposing reactions cease

c. speeds of opposite reactions become equal

d. temperature of opposite reactions become equal

Answer: c. speeds of opposite reactions become equal

Explanation:

Equilibrium state is the state when reactants and products are present but the concentrations does not change with time.The state of equilibrium refers to the dynamic state as both forward and backwad reactions continue.

For a chemical equilibrium reaction, equilibrium state is achieved when the rate of forward reaction becomes equals to rate of the backward reaction.

Thus at chemical equilibrium, the amount of product and reactant remains constant because the rates of the forward and reverse reactions are equal.

Answer:

0.847 molecule.

Explanation:

From the question given above, the following data were obtained:

Mass of X₄Z₃ = 3.93×10¯²² g

Number of molecules of X₄Z₃ =?

Avogadro's number = 6.022×10²³ molecules

Next, we shall determine the molar mass of X₄Z₃. This can be obtained as follow:

Molar mass of X₄Z₃ = (4×59.45) + (3×13.84)

= 237.8 + 41.52

= 279.32 g/mol

Finally, we shall determine the number of molecules in 3.93×10¯²² g of X₄Z₃. This can be obtained as follow:

From Avogadro's hypothesis,

1 mole of X₄Z₃ = 6.022×10²³ molecules

But 1 mole of X₄Z₃ = 279.32 g

Thus we can say that:

279.32 g = 6.022×10²³ molecules

Therefore,

3.93×10¯²² g = 3.93×10¯²² × 6.022×10²³ / 279.32

3.93×10¯²² g = 0.847 molecule.

Thus, 3.93×10¯²² g of X₄Z₃ contains 0.847 molecule.

Answer: 0.800 M

Basically, the ratio is 2:1, so when you have 1 M of Li2HPO4 it means you have 2 M in the concentration of lithium ions. So knowing the ratio, we know we just need to multiply 0.400 x 2.

I'm bad at explaining it, but got it right on chem101 sooo

The concentration of lithium ion, Li⁺ in 0.4 M Li₂HPO₄ is 0.8 M.

The concentration of a substance is simply the amount of the substance in 1 L of water.

To obtain the concentration of lithium ion, Li⁺ in Li₂HPO₄, we'll begin by writing the dissociation equation of Li₂HPO₄. This is illustrated below:

From the balanced equation above,

1 mole of Li₂HPO₄ produced 2 moles of Li²⁺.

Finally, we shall determine the concentration of lithium ion, Li⁺ in 0.4 M Li₂HPO₄. This can be obtained as follow:

From the balanced equation above,

1 mole of Li₂HPO₄ produced 2 mole of Li⁺.

Therefore, 0.4 M Li₂HPO₄ will produce = 2 × 0.4 = 0.8M Li²⁺

Thus, 0.8 M lithium ion, Li⁺ is present in the solution.

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Answer:

Explanation:

When calcium hydroxide is dissolved in water , it ionizes as follows .

Ca( OH)₂ = Ca⁺² + 2 OH ⁻

When it is dissolved in water which contains minimal OH⁻ , so there is almost no common ion effect . Hence calcium hydroxide is fully dissolved in pure water solvent .

When 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.500 M sodium hydroxide solution in beaker , it is not fully dissolved due to common ion of hydroxide ion ( OH⁻ )

NaOH = Na⁺ + OH⁻

OH⁻ ion from NaOH , suppresses the dissolution of calcium hydroxide .

Similarly

When A 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.200 M sodium hydroxide solution in beaker , it is not fully dissolved due to common ion of hydroxide ion ( OH⁻ )  

NaOH = Na⁺ + OH⁻

OH⁻ ion from NaOH , suppresses the dissolution of calcium hydroxide

When 1.00 mole sample of solid calcium hydroxide is added to 500.0 mL of 0.200 M calcium nitrate solution , it is not fully dissolved due to common ion of calcium  ion ( Ca⁺² )

Ca( NO₃)₂ = Ca⁺² + 2NO₃⁻

Ca⁺²  ion from Ca( NO₃)₂ , suppresses the dissolution of calcium hydroxide .

Answer:

A) alpha particle, beta particle, gamma ray

Explanation:

Alpha beta and gamma radiations are the examples of ionizing radiations. When an atom is an excited state and having high energy, the atom is in unstable state. The excess of energy is released by the atom to get the stability. The released energy is in the form of radiations which may include alpha, beta, gamma, X-ray etc.

Properties of alpha radiation:  

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

₉₂U²³⁸   →   ₉₀Th²³⁴  + ₂He⁴  + energy

Beta radiations:  

The mass of beta particle is smaller than the alpha particles.

They can travel in air in few meter distance.

These radiations can penetrate into the human skin.

The sheet of aluminum is used to block the beta radiation

⁴₆C → ¹⁴₇N + ⁰₋₁e

The beta radiations are emitted in this reaction. The one electron is ejected and neutron is converted into proton.  

Gamma radiations:

Gamma radiations are high energy radiations having no mass.

These radiations are travel at the speed of light.

Gamma radiations can penetrate into the many materials.

These radiations are also used to treat the cancer.

Lead is used for the protection  against gamma radiations because of its high molecular density.

The lead apron are used by the person when treated with gamma radiations.

Lead shields are also used in the wall, windows and doors of the room where gamma radiations are treated, in-order to protect the surroundings.

Answer:

55.6 °C

Explanation:

From the question given above, the following data were obtained:

Mass (M) of diamond = 32.0 g

Initial temperature (T₁) = 33.5°C

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Final temperature (T₂) =?

Next, we shall determine the change in temperature. This can be obtained as follow:

The final temperature can be obtained as follow:

Mass (M) of diamond = 32.0 g

Heat (Q) required = 360 J

Specific heat capacity (C) of diamond = 0.509 J/gºC

Change in temperature (ΔT ) =?

Q = MCΔT

360 = 32 × 0.509 × ΔT

360 = 16.288 × ΔT

Divide both side by 16.288

ΔT = 360 / 16.288

ΔT = 22.1 °C

Finally, we shall determine the final temperature. This can be obtained as follow:

Initial temperature (T₁) = 33.5°C

Change in temperature (ΔT ) = 22.1 °C

Final temperature (T₂) =?

ΔT = T₂ – T₁

22.1 = T₂ – 33.5

Collect like terms

22.1 + 33.5 = T₂

T₂ = 55.6 °C

Therefore, the final temperature is 55.6 °C.

Answer: Only non-polar medicines can diffuse across the membrane. non-polar drugs are lipid soluble, while polar drugs are water soluble, so polar drugs cant absorb through biological membranes.

Answer:

Explanation:

NaCl dissolves in water but not in benzene because the water-ion interactions are stronger than benzene-ion interactions.

This statement is true . NaCl is ionic compound . I water is ionises strongly because of strong ion - water interaction . It does not dissolve in benzene because of low ion - benzene interaction .

NaCl dissolves in water but not in hexane because the enthalpy of mixing NaCl with water is more negative than that of mixing NaCl with hexane.

This statement is wrong because enthalpy of mixing NaCl with water is positive and not negative .

NaCl dissolves in water but not in benzene(C6H6) because there are no hydrogen bonds in benzene.

This statement is wrong . NaCl does not make hydrogen bond with water molecule .

NaCl dissolves in water but not in benzene because the water-ion interactions are stronger than benzene-ion interactions.This statement is true .

The term ion is defined as an ion is an atom or molecule with a net electrical charge. There are two types of ions that are cation and anion.

This statement is true . NaCl is an ionic compound . The water is ionizes strongly because of strong ion - water interaction . It does not dissolve in benzene because of low ion - benzene interaction .

NaCl dissolves in water but not in hexane because the enthalpy of mixing NaCl with water is more negative than that of mixing NaCl with hexane. This statement is wrong because enthalpy of mixing NaCl with water is positive and not negative .

NaCl dissolves in water but not in benzene(C6H6) because there are no hydrogen bonds in benzene. This statement is wrong . Because NaCl does not make hydrogen bond with water molecule .

Thus, NaCl dissolves in water but not in benzene because the water-ion interactions are stronger than benzene-ion interactions.

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Answer:

I dunno,  what is the answer

Explanation:

Answer:

When some LiCl is dissolved in water, the temperature of the water increases. This means that: (A) the strength of the intermolecular forces between the water molecules is stronger than the bond energy within the LiCl lattice.

Explanation:

When Lithium chloride is dissolved in water, there is a steep rise in the temperature of the water. Based on this evidence, the dissolution of lithium chloride is exothermic.

An exothermic reaction may be defined as a type of reaction in which energy is liberated as a product in the form of light or heat. For these types of reactions, the overall standard enthalpy change ΔH⚬ is negative. It is one of the thermodynamic processes other than endothermic.

In the reaction, lithium intensely reacts with water in order to form lithium hydroxide and highly flammable hydrogen which liberated energy and leads to the steep rise in the temperature of the product compounds. This enhancement in the temperature is accurate evidence of an exothermic reaction.  

Therefore, on the basis of the evidence that the reaction of lithium chloride in water causes a steep rise in the temperature of the water represents an exothermic reaction.

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Answer:

[tex]M=1.05M[/tex]

Explanation:

Hello!

In this case, since the formula for the calculation of molarity is defined in terms of moles and volume in liters as shown below:

[tex]M=\frac{n}{V}[/tex]

Whereas the moles are computed by considering the molar mass of CaCO3 (100.09 g/mol):

[tex]n=47.4g*\frac{1mol}{100.09g}=0.4736mol[/tex]

Thus, we obtain:

[tex]M=\frac{0.4736mol}{0.450L}\\\\M=1.05M[/tex]

Best regards!