Check all that apply...helppppp

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:

Explanation:

Assumptions

Note

The concentrations would merely add. All things change if the assumptions I've made are not true.

Answer:

B.

Our pupils contract and expand depending on the amount of light at any given time in order to avoid being blinded and to see better in the darkness.

Answer:

[tex]\color{Blue}\huge\boxed{Answer} [/tex]

B.the electrons become delocalized and form a "sea"

Answer:

2.1 M

Explanation:

The dilution equation is [tex]M_{s} V_{s} = M_{d} V_{d}[/tex].

[tex]M_{s}[/tex] = the molarity of the sock solution

[tex]V_{s}[/tex] = the volume of the sock solution

[tex]M_{d}[/tex] = the molarity of the diluted solution

[tex]V_{d}[/tex] = the volume of the diluted solution

The stock solution would be what is doing the diluting, so "175 mL of a 3.00 M solution". So [tex]M_{s}[/tex] = 3.00 M. Then: Converting 175 mL to liters: [tex]175 mL * \frac{1 L}{1000mL} = 0.175 L[/tex] (This is [tex]V_{s}[/tex])

And converting 250 mL KCl to liters: [tex]250 mL * \frac{1 L}{1000mL} = 0.250 L[/tex] (This will be [tex]V_{d}[/tex])

Then, we plug in our given into the dilution equation, resulting in:

[tex]3.00 M * 0.175 L = M_{d} * 0.250 L[/tex] (divide both sides by 0.250 L, in order to get [tex]M_{d}[/tex] by itself)

[tex]\frac{3.00 M * 0.175 L}{0.250 L} = M_{d}[/tex]

[tex]M_{d} = 2.1 M[/tex]

So, the molarity of 250 mL KCl made by diluting 175 mL of a 3.0 M solution would be 2.1 M (mol/L).

Hopefully this helped you understand the topic a little bit better. I just finished molarity and dilutions in Chemistry last week. Good luck!

Answer:

The color black absorbs most colors, while white reflects most colors.

Answer:

The answer would be B. 1 joule/s.

Explanation:

The answer is B because the power in general is normally defined as energy over time. Watts are defined as 1 Watt = 1 Joule per second (1W = 1 J/s) which means that 1 kW = 1000 J/s.

Another reason why it's B is because I had the same exact question in class, I took a screenshot of it a day ago:

Hope this helps

Answer:

Wind

Explanation:

Wind turbines make energy by the movement of the natural force on earth called 'wind' and renewable resources are resources that can be made from natural and environment-safe objects or things (e.g. Water, Geothermal Heat, The Sun, and Wind)

Answer:

794 mmHg

Explanation:

We are going to be using the Combined Gas Law for this problem as well. Just to refresh out memory - the Combined Gas Law expresses the relationship between pressure, volume, and temperature (in KELVIN) of a fixed amount of gas. The equation itself? Right here: [tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]

Now, looking at the problem, let's assign the values to its corresponding variable:

P1 = 800mmHg; V1 = 5.0L; T1 = -50°C + 273 = 223K

V2 = 7.0L; T2 = 37°C + 273 = 310K; P2 = ?

We are looking to find the new pressure, a.k.a. P2. So, let's plug and chug the values into the equation.

Set up: [tex]\frac{(800 mmHg)(5.0L)}{223K} = \frac{(7.0L)(P_{2})}{310K}[/tex]

==> [tex]\frac{(800 mmHg)(5.0L)}{223K} * 310K = (7.0L)(P_{2})}[/tex]

==> [tex]P_{2} = \frac{(800 mmHg)(5.0L)}{223K} * \frac{310K}{7.0} }[/tex]

==> [tex]P_{2} =[/tex] 794.36 = 794 mmHg

Answer:

C

Explanation:

Check it. So u can know it

Answer:

thank u

Explanation:

Answer:

B. The cells.

call

Cells are considered the basic units of life in part because they come in discrete and easily recognizable packages. That's because all cells are surrounded by a structure called the cell membrane — which, much like the walls of a house, serves as a clear boundary between the cell's internal and external environments.

Answer:

1.62x10⁻¹² M

Explanation:

HClO₃ is a strong acid, meaning that a 6.2x10⁻³ M solution has a molar concentration of H⁺ of 6.2x10⁻³.

With the above information in mind, we can calculate the pH of the solution:

Now we can calculate the pOH of the solution, using the pH:

Finally we calculate [OH⁻], using the definition of pOH:

Answer:

-security hardware

- artificial intelligence

wifi, internet, phones, voice assistants, drones.

Answer:

A five-sided polygon.- cyclopentane

A square.- cyclobutane

A five-sided polygon with one line extending from a point.- methylcyclopentane

A 6-sided polygon with a line extending from one point to a C H 3.- methlcyclohexane

Explanation:

The correct options are :

Cycloalkane is a cyclic hydrocarbon meaning that the carbon of the molecules is arranged in the form of a ring. These are also saturated and all of the carbon stems make up a ring.

These are monocyclic and made from hydrogen and carbon. One ring structure is named after cyclo. Cyclobutane is columns gases and is available in liquefied gas.

Find out more information about the cycloalkanes.

brainly.com/question/10189586

Answer:

i hope i can help you with this

Answer: focus in class

Explanation:

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1Al2(SO4)3 + 3ZnCl2 → 2AlCl3 + 3ZnSO4

The coefficients represents moles. There is 1 mole of Aluminum Sulfate, 3 moles of Zinc(II) Chloride, 2 moles of Aluminum Chloride, and 3 moles of Zinc(II) Sulfate.

Now add all the coefficients/moles.

9 is the sum of all the coefficients.

Explanation:

2,4-DNP is negative: aldehyde and ketone absent

Chromic acid is negative: alcohol absent.

KMnO4 test negative: alkene absent

The only positive result is for Fe(OH)2.

Nitro group-containing compounds react with ferrous hydroxide to give amine and ferric hydroxide red ppt. Hence given compound contains the nitro group (-NO2).

Answer:

A.The sound becomes louder.

And

C.The sound waves get further.

Explanation:

Louder the sound it will travel long.

Answer:

B i think

Explanation:

Answer:

0.083 M

Explanation:

We'll begin by calculating the number of mole in 0.43 g of KHP (potassium hydrogen phthalate, C₈H₅O₄K). This is can be obtained as follow:

Mass of C₈H₅O₄K = 0.43 g

Molar mass of C₈H₅O₄K = (8×12) + (5×1) + (16× 4) + 39

= 96 + 5 + 64 + 39 = 204 g/mol

Mole of C₈H₅O₄K =?

Mole = mass / molar mass

Mole of C₈H₅O₄K = 0.43 / 204

Mole of C₈H₅O₄K = 0.002 mole

Next, we shall determine the number of mole of NaOH required to react with 0.43 g (i.e 0.002 mole) of KHP. This can be obtained as follow:

C₈H₅O₄K + NaOH → C₈H₄O₄KNa + H₂O

From the balanced equation above,

1 mole of KHP reacted with 1 mole of NaOH.

Therefore, 0.002 mole of KHP will also react with 0.002 mole of NaOH.

Next, we shall convert 24.11 cm³ to L. This can be obtained as follow:

1000 cm³ = 1 L

Therefore,

24.11 cm³ = 24.11 cm³ × 1 L / 1000 cm³

24.11 cm³ = 0.02411 L

Finally, we shall determine the molarity of NaOH. This can be obtained as follow:

Mole of NaOH = 0.00 2 mole

Volume = 0.02411 L

Molarity of NaOH =?

Molarity = mole /Volume

Molarity of NaOH = 0.002 / 0.02411

Molarity of NaOH = 0.083 M

Answer:

c balance

Explanation:

if you weigh something, you prove it's there.

Answer:   First we need to know how many moles of each reactant there are.

C6H12O6 :         25g/180.06g/mol=0.1388mol

O2:                    40g/32g/mol=1.25mol

The equation tells us we need 6 moles of O2 for every 1 mole of Glucose.

6 x 0.1388 = 0.8328

So, we have more O2 then needed – it is in excess.

Glucose is the limiting reagent – we use this for the calculation.

The equation tells us we make 6 moles of CO2 for every 1 mole of Glucose

So, we make 0,8328 moles of Carbon Dioxide

Explanation:

Answer: -3.6

Explanation:

The lowest pH of -3.6 is the lowest known for any water in the environment

Answer:

18.18C

Explanation: Write whats below to show your work :D

m=55

C=0.45

Q=450zj

ch.temp=?

Q=mct

450 = (55)(.45)T

450 = 24.75

/24.75 = /24.75 (cancels out)

18.18 is the answer

Hope this helps! did it with my teacher.

Answer:

Evaporation happens when a liquid substance becomes a gas. When water is heated, it evaporates. The molecules move and vibrate so quickly that they escape into the atmosphere as molecules of water vapor. ... Once water evaporates, it also helps form clouds

Answer: D

Explanation:  Irregular galaxies

Answer:

Your answer is D

Explanation:

Irregular galaxies do not have a regular structure.