At midnight in the dark of the night, what is most likely happening in a leaf? * O Respiration O Photosynthesis O Both photosynthesis and respiration Neither photosynthesis or respiration

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Answer:

it's answer is A

A nonspotaneous redox reaction

hope it helps you

Answer:

K

Explanation:

Ionization energy refers to the energy required to remove an electron from an atom. It usually increases across the period due to the increase in the size of the nuclear charge and decreases down the group due to increase in the number of shells.

If we look at the element, K, it has only one electron in its outermost shell. This implies that after this one electron is removed, the second ionization energy involves the removal of an electron from a filled shell.

This usually requires a lot of energy. Hence, the element having the highest difference in energy between first and second ionization energy is K.  

Answer:

[PbNO₃] = 3.13 M

Explanation:

Molarity is a specific sort of concentration where we have, the amount of solute's moles contained in 1 L of solution.

In this case, our solution's volume is 500 mL.

We convert to L → 500mL . 1L/1000 mL = 0.5L

Moles → 1.565 mol

Molarity (mol/L) → 1.565 mol / 0.5L = 3.13 M

There also types of concentration, for example molality which indicates the moles of solute in 1kg of solvent.

Answer:

Mn is the oxidizing agent.

N is the reducing agent.

Explanation:

Hello!

In this case, according to the undergoing chemical reaction, it is seen that the manganese in KMnO4 has an oxidation state of 7+, in MnSO4 of 2+ and nitrogen in KNO2 is 3+ and in KNO3 is 5+; thus we have the following half-reactions:

[tex]Mn^{7+}+5e^-\rightarrow Mn^{2+}\\\\N^{3+}\rightarrow N^{5+}+2e^-[/tex]

Thus, since manganese is undergoing a decrease in the oxidation state, we infer it is the oxidizing agent whereas nitrogen, undergoing an increase in the oxidation state is the reducing agent.

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Answer:

3.02

Explanation:

Step 1: Given and required acid

pH of the solution: 4.34

pKa of lactic acid: 3.86

Step 2: Calculate the ratio of the lactate concentration to the lactic acid concentration in this solution

We have a buffer system formed by a weak acid (lactic acid) and its conjugate base (lactate ion). We can find the ratio of the lactate concentration to the lactic acid concentration in this solution using the Henderson-Hasselbach equation.

pH = pKa + log [lactate]/[lactic acid]

4.34 = 3.86 + log [lactate]/[lactic acid]

[lactate]/[lactic acid] = 3.02

Answer:

formula of starch is (C6H10O5)n, where n is the number of glucose molecules in the chain.

Explanation:

Mass of X₄Z₅= 378.621 g

Given

3.89 x 10²³ molecules/formula units of X₄Z₅

Required

Mass of X₄Z₅

Solution

1 mol = 6.022 x 10²³ particles(molecules, atoms, ions)

N = n x No

No = Avogadro's number

n = mol

Conversion to mol :

n = N : No

n = 3.89 x 10²³ : 6.022 x 10²³

n = 0.646

MW X₄Z₅ :

= 4 x 76.15 + 5 x 56.3

= 304.6 + 281.5

= 586.1 g/mol

Mass :

= mol x MW

= 0.646 x 586.1

= 378.621 g

Answer:

d 1 1/2 oz.. of 80-proof liquor

1 1/2 oz. of 80-proof liquor is not equivalent to one drink. Hence, option D is correct.

Oz is an abbreviation for ounce. An ounce is equal to 1/16 pound (437 1/2 grains) and equal to 480 grains, or 1/12 pound.

1 1/2 oz. of 80-proof liquor is not equivalent to one drink.

Hence, option D is correct.

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Answer:

Density, Mass, Pressure

Answer:

It becomes insoluble again.

Explanation:

The chemical equation showing the reaction between benzoic acid, and sodium hydroxide,NaOH is given below;

C6H5COOH + NaOH ------------------------> C6H5COO^- Na^+ + H2O.

The Benzoic acid, C6H5COOH is insoluble but when it reacted with 1M Sodium hydroxide, NaOH it changes to sodium benzoate, C6H5COO^- Na^+ which is more soluble than the benzoic acid.

C6H5COO^- Na^+ + HCl -------------------> C6H5COOH + NaCl.

When the sodium benzoate, C6H5COO^- Na^+ reacts with 6M HCl, it is converted back to benzoic acid which is insoluble. Hence, precipitation is observed.

Answer:

Mountains are formed from the collision of the earths tectonic plates and they are formed at different times because of the geologi activity below them

Explanation:

Answer:

crystalline and amorphous.

Explanation:

Crystalline solids are the most common type of solid, they are characterized by a regular crystalline organization of atoms that confer a long-range order, Amorphous, or non-crystalline, solids lack the long-range order

Answer:

an unbalanced force

Explanation:

Answer:

The type of plate boundary between the South American Plate and the African Plate is a divergent one.

The two plates move apart from each other.

Explanation:

The boundary between the South American Plate and the African Plate is a divergent boundary. The plates moved, and between them, there is an oceanic basin. The plates move on top of the mantle, and magma goes up the divergent areas creating new surfaces when it solidifies. The new surface is called a ridge.

Answer:

12.4 * 10^-8 m or 1.24 * 10^--7 m or 124 nm

Explanation:

We have to obtain the energy of the N≡N triple bond in joules as follows;

E = 945 * 1000/6.02 * 10^23 = 9.45 * 10^5/6.02 * 10^23

E = 1.6 * 10^-18 J

But;

E = hc/λ

h = Planks constant

c = speed of light

λ = wavelength of light

λ = hc/E

λ= 6.6 * 10^-34 * 3 * 10^8/1.6 * 10^-18

λ = 12.4 * 10^-8 m or 1.24 * 10^--7 m or  124 nm

Answer:

The solid particles will be trapped behind on the strainer while the liquid molecules will pass or filter through.

Explanation:

Filtration is a process of separation of mixtures involving an insoluble solid and a fluid such as liquids or gases using a filtering medium such as paper or cloth or any other material. During the process, the liquid molecules pass through the filtering medium whereas the solid particles are not allowed to pass through but are retained by the medium. The reason is that the pores on the filtering medium are only small enough for the liquid molecules to pass through but not the solid particles.

An example of a mixture that can be separated through filtration is a suspension of chalk and water. Also, a mixture of water and solid particles such as water and tea leaves can also be separated using a strainer with cloth.

In the question, if a mixture of insoluble solids in a liquid is passed through a strainer with cloth, the solid particles will be trapped behind on the strainer while the liquid molecules will pass through.

Filtration is a technique in which the solute and the solvent can be separated. This technique is based upon the size of the solute particle.

Therefore, if the mixture of insoluble solid is separated from a solvent then the solid will be retained on the cloth of the strainer while the liquid will flow through.

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Answer:

visual ob

Explanation:

Answer:

all of the above

because these use all of your 5 senses

a very strong Abiotic factor in the world is the sun it let's off vitamin d and it can burn humans to were you get skin cancer so the sun

Answer:

Cr₂S₃

Explanation:

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

Mass of chromium (Cr) = 0.67 g

Mass of chromium sulfide = 1.2888 g

Empirical formula =?

Next, we shall determine the mass of sulphur (S) in the compound. This can be obtained as follow:

Mass of chromium (Cr) = 0.67 g

Mass of chromium sulfide = 1.2888 g

Mass of sulphur (S) =?

Mass of S = (Mass of chromium sulfide) – (Mass of Cr)

Mass of S = 1.2888 – 0.67

Mass of S = 0.6188 g

Finally, we shall determine the empirical formula of the compound. This can be obtained as follow:

Mass of Cr = 0.67 g

Mass of S = 0.6188 g

Divide by their molar mass

Cr = 0.67 / 52 = 0.013

S = 0.6188 / 32 = 0.019

Divide by the smallest

Cr = 0.013 / 0.013 = 1

S = 0.019 / 0.013 = 1.46

Multiply by 2 to express in whole number

Cr = 1 × 2 = 2

S = 1.46 × 2 = 3

Therefore, the empirical formula of the compound is Cr₂S₃

The empirical formula will be "[tex]Cr_2 S_3[/tex]".

Given:

Mass of Cr,

Mass of product,

Now,

→ [tex]Mass \ of \ Sulphur = Mass \ of \ product -Mass \ of \ Cr[/tex]

                                [tex]= 1.2888-0.67[/tex]

                                [tex]= 0.6188 \ g[/tex]

then,

→ [tex]Moles \ ratio \ of \ Cr:S = (\frac{0.67}{51.996} ): (\frac{0.61888}{32} )[/tex]

                                       [tex]= 0.0129: 0.0194[/tex]

                                       [tex]= 2:3[/tex]

Thus the above response is right.

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Answer:

0.020 mg

Explanation:

Let assume that the amount of the dissolved acetaminophen is (10. to 30/μgml); &

the volume of blood sample is = 2ml

We need to understand that the minimum mass of the acetaminophen that can be detected by the new system is = 10 μgml × 2

= 20 μg

= (20/1000) mg

= 0.020 mg

Answer:

H₂O is the excess reactant

Explanation:

A reactant is in excess when the other reactant is over and the first reactant is still present.

For the reaction:

Mg₂Si (s) 4H₂O (l) → 2Mg(OH)₂(aq) + SiH₄ (g)

We need to convert mass of each reactant to moles in order to find which reactant is in excess as follows:

Moles Mg₂Si -Molar mass: 76.7g/mol-:

50.0g * (1mol / 76.7g) = 0.652 moles of Mg₂Si

Moles H₂O - Molar mass: 18.02g/mol-:

50.0g * (1mol / 18.02g) = 2.78 moles of H₂O

For a complete reaction of 2.78 moles of H₂O are required:

2.78mol H₂O * (1mol Mg₂Si / 4mol H₂O) = 0.694 moles Mg₂Si

As there are just 0.652 moles, Mg₂Si is limiting reactant and

Answer:

[tex]^{127}_{53} I[/tex]

53 protons and electrons and 74 neutrons.

Explanation:

Hello!

In this case, since the nuclide symbol of an isotope is represented by putting the atomic mass as a prefixed superscript and the number of protons as a prefixed subscript, for I-127 we have:

[tex]^{127}_{53} I[/tex]

Now we realize this isotope have 53 electrons and protons and the following number of neutrons:

[tex]neutrons= 127-53=74[/tex]

Notice this isotope has about the same molar mass of the average iodine atom.

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Answer:

I think this means that they always compatible so th er e basically friends and they stick together. c: hope I helped

Answer:

I think the answer is h

Explanation:

when you let the balloon go, all the air the is inside comes out causing it to move forard

Answer:

Substance D would be the correct answer.

Answer:

1.54 x 10⁻¹¹kg

Explanation:

The charge to mass ratio is given as:

               1.044 x 10⁻⁸kg/C

 Charge on the proton  = 1.602 x 10⁻¹⁹C

 So;

    [tex]\frac{e}{m}[/tex]   is the charge to mass ration

e is the charge

m is the mass

  1.044 x 10⁻⁸kg/C  = [tex]\frac{1.602 x 10^{-19} }{m}[/tex]    

    m = [tex]\frac{1.602 x 10^{-19} }{1.044 x 10^{-8} }[/tex]   = 1.54 x 10⁻¹¹kg

Answer:

the partial pressure of methane CH₄ is 239.4 torr.

Explanation:

Given;

molar mass of methane, CH₄ = 90.0 g

molar mass of argon, Ar = 10.0 g

total pressure of the gases, Pt = 250 torr

number of moles of methane CH₄;

[tex]n_{CH_4} = \frac{90}{16} = 5.625 \ moles[/tex]

number of moles of Ar;

[tex]n_{Ar} = \frac{10}{39.95} = 0.25 \ mole[/tex]

The mole fraction of methane XCH₄ is calculated as;

[tex]X_{CH_4} = \frac{n_{CH_4} }{n_{CH_4} \ + \ n_{Ar}} \\\\X_{CH_4} = \frac{5.625}{5.625 \ + \ 0.25} \\\\X_{CH_4} = 0.9575[/tex]

Apply Dalton's law of partial pressure, to determine the partial pressure of methane CH₄;

[tex]P_{CH_4} = X_{CH_4} P_t\\\\P_{CH_4} = 0.9575 \ \times \ 250 \ torr\\\\P_{CH_4} = 239.4 \ torr[/tex]

Therefore, the partial pressure of methane CH₄ is 239.4 torr.

The partial pressure of CH₄ in the mixture containing 90 g of CH₄ and 10 g of Ar having a total pressure of 250 torr is 239.25 torr

We'll begin by calculating the number of mole of CH₄ and Ar. This can be obtained as follow:

Mass of CH₄ = 90 g

Molar mass of CH₄ = 12 + (4×1) = 16 g/mol

Mole = mass / molar mass

Mole of CH₄ = 90 / 16

Mass of Ar = 10 g

Molar mass of Ar = 40 g/mol

Mole = mass / molar mass

Mole of Ar = 10 / 40

Mole of CH₄ = 5.625 mole

Mole of Ar = 0.25 mole

Total mole = 5.625 + 0.25

Total mole = 5.875 mole

Mole fraction = mole of substance / total mole

Mole fraction of CH₄ = 5.625 / 5.875

Mole fraction of CH₄ = 0.957

Total pressure = 250 torr

Partial pressure = mole fraction × total pressure

Partial pressure of CH₄ = 0.957 × 250

Therefore, the partial pressure of CH₄ in the mixture is 239.25 torr

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Answer:

3.63s take for the concentration of NO₂ to decrease from 0.62M to 0.28M

Explanation:

The general equation for a second-order reaction is:

1/[A] = kt + 1/[A]₀

Where [A] is actual concentration of the reactant (0.28M)

k is rate constant (0.54M⁻¹s⁻¹)

t is time the reaction takes (Our incognite)

And [A]₀ is initial concentration of reactant (0.62M)

Replacing:

1/0.28M = 0.54M⁻¹s⁻¹t + 1/0.62M

3.5714 = 0.54t + 1.6129

1.9585 = 0.54t

3.63s = t

Answer:

Enthalpy of formation of strontium chloride, SrCl = -558.1 kJ/mol

Explanation:

Sr(s) -------> Sr(g)       ΔHsublimation = +164 kJ/mol

Sr⁺(g) -------> Sr⁺(g)    First Ionization energy, IE₁ = +549 kJ/mol

Sr⁺(g) -------> Sr²⁺(g)    Second ionization energy, IE₂ = +1064 kJ/mol

I₂(s) --------> I₂(g)   ΔHsublimation = +62.4 kJ/mol

I₂(g) -------> 2I(g)   Bond dissociation energy, BE = +152.55 kJ/mol

2I(g) ----> 2I⁻(g)   Electron affinity, EA = 2 (-295.15 kJ/mol) = -590.3 kJ/mol

Sr²⁺(g) + 2I⁻(g) ------> SrI₂(s)    Lattice energy, LE = -1959.75 kJ/mol

Overall equation for the formation of SrCl₂ is given as:

Sr(s) + I₂(s) ----> SrI₂(s)    ΔHformation = ?

Enthalpy of formation, ΔHformation = (ΔHsublimation of Sr(s) + IE₁ + IE₂ + ΔHsublimation of I₂(s) + BE + EA + LE)

ΔHformation = {164 + 549 + 1064 + 62.4 + 152.55 + (-590.3) + (-1959.75)} kJ/mol

Sr(s) + I₂(s) ----> SrI₂(s)    ΔHformation = -558 kJ/mol

Therefore, enthalpy of formation of strontium chloride, SrCl = -558.1 kJ/mol

Answer:

0.8878 mol KClO4

Explanation:

Molar mass of KClO4 = 39.0983 + 35.453 + ( 15.9994 x 4 ) = 39.0983 + 35.453 + 63.9976 = 138.5489g/mol

but,

number of moles = mass in grams / molar mass where mass in grams = 123g, molar mass = 138.5489g/mol

number of moles = 123g / 138.5489g/mol = 0.8878mol

Therefore the number of moles present in 123 g of [tex] KClO_4[/tex] is 0.888 moles.

Given,

The weight of the [tex] KClO_4[/tex] is 123. grams

molecular weight of [tex] KClO_4[/tex] is [tex]39+35.5+16\times4=138.5 g[/tex]

138.5 g of [tex]KclO_4[/tex] is equal to one mole

Gram molecular wt. of a substance is equal to one mole

No. of moles = [tex]\frac{Wt}{GMW} [/tex]

123 g of [tex]KClO_4[/tex] is equal to [tex]\frac{123}{138.5}=0.888 moles [/tex]

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