Why are half-reactions used in redox reactions?

Answer:

first one pure

second one mixture..

mass percent = (mass of element in 1 mole of compound / mass of 1 mole of compound) x 100. The formula for a solution is:

mass percent = (grams of solute / grams of solute plus solvent) x 100. or.

mass percent = (grams of solute / grams of solution) x 100. The final answer is given as %.

Hope this helps!!

Explanation:

use the conversation in the image

Answer: The concentration of [tex]H_2SO_4[/tex] is 0.234 M

Explanation:

According to the neutralization law,

[tex]n_1M_1V_1=n_2M_2V_2[/tex]

where,

[tex]n_1[/tex] = basicity [tex]H_2SO_4[/tex] = 2

[tex]M_1[/tex] = molarity of [tex]H_2SO_4[/tex] solution = ?

[tex]V_1[/tex] = volume of  [tex]H_2SO_4[/tex] solution = 50.0 ml

[tex]n_2[/tex] = acidity of [tex]NaOH[/tex] = 1

[tex]M_1[/tex] = molarity of [tex]NaOH[/tex] solution = 0.375 M

[tex]V_1[/tex] = volume of  [tex]NaOH[/tex] solution = 62.5 ml

Putting in the values we get:

[tex]2\times M_1\times 50.0=1\times 0.375\times 62.5[/tex]

[tex]M_1=0.234M[/tex]

Therefore concentration of [tex]H_2SO_4[/tex] is 0.234 M

Answer:

Explanation:

ABC Powder: sprays a very fine chemical powder. This acts to blanket the fire and suffocate it. Class A, B, C fires

Carbon dioxide: extinguishes CO2. By doing so, it removes oxygen from the fire, effectively suffocating it of oxygen. Class B fires

Foam: spray a type of foam that expands when it hits the air and blankets the fire. This prevents the vapors from rising off the liquid to feed the fire, thus starving it of fuel. Class A and B

Water: releases microscopic water molecules that fight the fire on a variety of levels. the level of oxygen in the air is decreased, which helps to suffocate the fire. Class: most all

also, your fire classes:

Class A: freely burning, combustible solid materials such as wood or paper

Class B: flammable liquid or gas

Class C: energized electrical fire (energized electrical source serves as the ignitor of a class A or B fire – if electrical source is removed, it is no longer a class C fire)

Class D: metallic fire (titanium, zirconium, magnesium, sodium)

Class K: cooking fires – animal or vegetable oils or fats

Answer:

dfgh

Explanation:

We're given the [OH⁻] as 8.34 × 10⁻¹² M. Using the formula pOH = -log[OH⁻], the pOH of this solution would be -log(8.34 × 10⁻¹²) ≈ 11.08.

The pOH is, for lack of a better term, the "opposite" of pH: A pOH of 7 is neutral; a pOH less than 7 is basic; and a pOH greater than 7 is acidic.

This follows from the relation, pH + pOH = 14. In this case, with a pOH of 11.08, our pH would be 14 - 11.08 = 2.92, which is acidic (pH < 7).

Thus, the correct answer choice is B.

Answer:

The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from

n

i

=

2

to

n

f

=

6

.

A good starting point here will be to calculate the energy of the photon emitted when the electron falls from

n

i

=

6

to

n

f

=

2

by using the Rydberg equation.

1

λ

=

R

⋅

(

1

n

2

f

−

1

n

2

i

)

Here

λ

si the wavelength of the emittted photon

R

is the Rydberg constant, equal to

1.097

⋅

10

7

m

−

1

Plug in your values to find

1

λ

=

1.097

⋅

10

7

.

m

−

1

⋅

(

1

2

2

−

1

6

2

)

1

λ

=

2.4378

⋅

10

6

.

m

−

1

This means that you have

λ

=

4.10

⋅

10

−

7

.

m

So, you know that when an electron falls from

n

i

=

6

to

n

f

=

2

, a photon of wavelength

410 nm

is emitted. This implies that in order for the electron to jump from

n

i

=

2

to

n

f

=

6

, it must absorb a photon of the same wavelength.

Answer:

1. Practice healthy habits with kids in your life. ...

2. Engage in your school's efforts to encourage healthy practices. ...

3. Learn more about the decisions local officials are making that impact your environment. ...

4. Give back healthy options to your community.

Explanation:

I think it's true.

Explanation:

Muscles move bones through contracting and relaxing

Answer:

a. pH = 2.04

b. pH = 3.85

c. pH = 8.06

d. pH = 11.56

Explanation:

The nitrous acid is a weak acid (Ka = 5.6x10⁻⁴) that reacts with NaOH as follows:

HNO₂ + NaOH → NaNO₂(aq) + H₂O(l)

a. At the beginning there is just a solution of 0.12M HNO₂. As Ka is:

Ka = [H⁺] [NO₂⁻] / [HNO₂]

Where [H⁺] and [NO₂⁻] ions comes from the same equilibrium ([H⁺] = [NO₂⁻] = X):

5.6x10⁻⁴ = X² / 0.15M

8.4x10⁻⁵ = X²

X = [H⁺] = 9.165x10⁻³M

As pH = -log [H⁺]

b. At this point we have HNO₂ and NaNO₂ (The weak acid and the conjugate base), a buffer. The pH of a buffer is obtained using H-H equation:

pH = pKa + log [NaNO₂] / [HNO₂]

Where pH is the pH of the buffer,

pKa is -log Ka = 3.25

And [NaNO₂] [HNO₂] could be taken as the moles of each compound.

The initial moles of HNO₂ are:

0.100L * (0.15mol / L) = 0.015moles

The moles of base added are:

0.0800L * (0.15mol / L) = 0.012moles

The moles of base added = Moles of NaNO₂ produced = 0.012moles.

And the moles of HNO₂ that remains are:

0.015moles - 0.012moles = 0.003moles

Replacing in H-H equation:

pH = 3.25 + log [0.012moles] / [0.003moles]

c. At equivalence point all HNO2 reacts producing NaNO₂. The volume added of NaOH must be 100mL. That means the concentration of the NaNO₂ is:

0.15M / 2 = 0.075M

The NaNO₂ is in equilibrium with water as follows:

NaNO₂(aq) + H₂O(l) ⇄ HNO₂(aq) + OH⁻(aq) + Na⁺

The equilibrium constant, kb, is:

Kb = Kw/Ka = 1x10⁻¹⁴ / 5.6x10⁻⁴ = 1.79x10⁻¹¹ = [OH⁻] [HNO₂] / [NaNO₂]

Where [OH⁻] = [HNO₂] = x

[NaNO₂] = 0.075M

1.79x10⁻¹¹ = [X] [X] / [0.075M]

1.34x10⁻¹² = X²

X = 1.16x10⁻⁶M = [OH⁻]

pOH = -log [OH-] = 5.94

pH = 14-pOH

d. At this point, 5mL of NaOH are added in excess, the moles are:

5mL = 5x10⁻³L * (0.15mol / L) =7.5x10⁻⁴moles NaOH

In 100mL + 105mL = 205mL = 0.205L. [NaOH] = 7.5x10⁻⁴moles NaOH / 0.205L =

3.66x10⁻³M = [OH⁻]

pOH = 2.44

pH = 14 - pOH

Answer:

Its a punnet square

Explanation:

Answer:Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely. Instead of orbiting their respective atoms, they form a sea of electrons that surround the positive nuclei of the interacting metal ions.

Explanation:

Answer:

While measuring relative density of liquids, two common method of measuring the volume are a measuring cylinder and a density bottle. Among these two method the density bottle gives more accurate measurement of the volume, resulting in more accurate determination of density or relative density

Answer:

While measuring relative density of liquids, two common method of measuring the volume are a measuring cylinder and a density bottle. Among these two method the density bottle gives more accurate measurement of the volume, resulting in more accurate determination of density or relative density.

Explanation:

Answer:

A

Explanation:

Answer:

A. occur, in the chloroplast.

Explanation:

Photosynthesis occur in chloroplasts, with the help of sunlight. Where mitochondria help in respiration

Answer: 0.144 moles. :)

Explanation:

The number  of  moles of NaCl that are contained in 50.0 mL of 2.50 M NaCl is 0.125 moles

Using this formula

Molarity=Moles of solute/Liters of solution

First step is to convert 50.0 mL to Liters

Litres=50.0 ml×1 L/1000 ml

Litres=0.05 L

Now let determie the number of moles of NaCl

2.50M=moles/0.05

moles=2.50M(0.05)

moles = 0.125 moles of NaCl

Inconclusion The number  of  moles of NaCl that are contained in 50.0 mL of 2.50 M NaCl is 0.125 moles

Learn more here:

https://brainly.com/question/2229605

Answer:

the reducing agent is Bromine

The oxidation state of an element is calculated by subtracting and the total sum of oxidation states of all the individual atom (excluding the one that has to be calculated) from total charge on the molecule. Bromine is the reducing agent in the following reaction.

Oxidation state of an element is a number that is assigned to an element in a molecule that represents the number of electron gained or lost during the formation of that molecule or compound.

The ionic equation is given as

2 Br⁻(aq) + H[tex]_2[/tex]O[tex]_2[/tex](aq) + 2 H⁺(aq) → Br[tex]_2[/tex](aq) + 2 H[tex]_2[/tex]O(l)

The oxidation state of bromine on reactant side is -1 while on product side it is 0 so, oxidation state of bromine has increased by 1 so,  bromine is oxidized. If it is oxidized that means it must have reduced someone. So, bromine is acting as a reducing agent.

Therefore, bromine is the reducing agent in the given reaction.

To learn more about Oxidation state, here:

https://brainly.com/question/11313964

#SPJ2

3. Convection Current

But just a tip Next time try to emphasize the question a little more ! Hope this helps :)

Answer:

1. 24.45 moles

2. 437.90 grams

Bonus :

0.75 grams

Explanation:

Hope it was helpful ;)

Answer:

deez cutz

Explanation:

did i get it right

Answer:

zygote

Explanation:

I got this online

Answer:

=> In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell (male gamete)—combine to form a single 2n diploid cell called the zygote.

ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ

[tex] \infty \infty [/tex]

Answer:

1

because a dwarf star will seemlarge because of the in ability of any human being to see d sun

Answer:

4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.

Explanation:

Molarity is a measure of concentration that indicates 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:

[tex]Molarity=\frac{number of moles}{volume}[/tex]

Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].

In this case:

Replacing in the definition of molarity:

[tex]0.240 M=\frac{number of moles}{0.125 L}[/tex]

Solving:

number of moles= 0.240 M*0.125 L

number of moles= 0.03 moles

Being the molar mass of sodium phosphate 164 g/mole, that is, the mass of one mole of the compound, you can calculate the mass of 0.03 moles using the following rule of three: if 1 mole of the compound has 164 grams, 0.03 moles contains how much mass?

[tex]mass=\frac{0.03 moles*164 grams}{1 mole}[/tex]

mass= 4.92 grams

4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.

Answer:

10.5 g

Explanation:

Step 1: Given data

Step 2: Calculate the moles of solute (n)

Molarity is equal to the moles of solute divided by the liters of solution.

M = n/V

n = M × V

n = 0.243 mol/L × 0.580 L = 0.141 mol

Step 3: Calculate the mass corresponding to 0.141 moles of KCl

The molar mass of KCl is 74.55 g/mol.

0.141 mol × 74.55 g/mol = 10.5 g