how much naoh must be added to 350 ml of 0.150m hf (pka = 3.45) in order to create a buffer with a ph of 4.00

Answer:

the group 0 elements, the noble glass. are all unreactive ,non-metal gases . they show trends in their physical properties.

Explanation:

their uses depend on their inertness.

Answer:

1 mole represents 6.023×1023 particles.

1 mole of iodine atom= 6.023×1023

Given 127.0g of iodine.

no. of iodine atom = 1 mole of iodine

1mole of magnesium = 24g of Mg = 6.023×1023no.of Mg

Given 48g of Mg = 2×6.023×1023

no. of Mg = 2 moles of Mg

1 mole of chlorine atom= 6.023× 1023

no. of chlorine atom = 35.5g of chlorine atom

Given 71g of chlorine atom=2× 6.023× 1023

no. of chlorine atom = 6.023×1023

2 moles of chlorine atom.

Given that 4g of hydrogen atom.

will be equal to 4 × 6.023 × 1023

no. of atoms of hydrogen= 4 moles of hydrogen atom.

Answer:

cause pollution on a small scale can make big difference......

Explanation:

factory isn't a single source of pollution

there are many more.....

Irony: a situation in which there is a contrast between expectation and reality.Irony can take many different forms.

The verbal irony, dramatic irony, and situational irony are the three types .Irony occurs in literature AND in life whenever a person says something or does something that departs from what they (or we) expect them to say or do.

Irony in the story 'Dusk':

Ironically, the main character, who thinks he is a good character judge, is duped by the young man who sat next to him on the park seat.

According to Gortsby, darkness is a time when dejected and shady people emerge.

The term irony has its roots in the Greek comic character Eiron, a clever underdog who by his wit repeatedly triumphs over the boastful character Alazon. The Socratic irony of the Platonic dialogues derives from this comic origin.

FIND MORE:-https://brainly.in/question/28085927

#SPJ4

The statement is False

If the weather station is completely filled in, the sky is considered to have 8/8 cloud cover or 80/100 cloud cover, indicating that the entire sky is covered in clouds.

The small flag indicating wind direction on a station weather plot points in the direction from which the wind is coming. This convention is followed to ensure consistency and to avoid confusion. By pointing in the direction from which the wind is coming, it allows observers to easily understand the wind's direction relative to the station's location.

The amount of the sky covered in clouds can be determined by using a system called the cloud cover code, which is represented in eighths or octas. Each octa represents one-eighth of the sky. So, if the weather station is completely filled in, it means the sky is completely covered in clouds, which corresponds to eight octas or 8/8 cloud cover.

Cloud cover is often reported in terms of tenths as well. In this case, each tenth represents 1/10th of the sky. To convert from octas to tenths, we multiply the octas by 10. Therefore, if the sky is completely filled in with clouds (8 octas), it would be equivalent to 8/8 or 80/100 cloud cover, which is 80% of the sky covered in clouds.

for more question on weather

https://brainly.com/question/29709289

#SPJ8

1. Water flows through the penstock

2. The water then spins the blades in a turbine which, in turn, spins a generator that ultimately produces electrical energy

Hydropower, or hydroelectric power, is one of the oldest and largest sources of renewable energy, which uses the natural flow of moving water to generate electrical energy. The moving water is passed through a pipe also known as penstock, it then turns the blade of the turbine. which then rolls or spin a generator thereby electricity is produced.

The work of the turbine is to convert the kinetic energy of the running water into useable energy.

learn more about conversion of water to electrical energy from

https://brainly.com/question/18776929

#SPJ1

Answer:

A to show that the mass of atoms in the product

Answer:

ide

Explanation:

the metal keeps its name in an ionic compound, the suffix of the nonmetal is changed to "ide" (ie sodium chloride, NaCl)

The percent yield for this reaction is 50.8%.

First, we need to determine the moles of p-phenetidine used:

Moles of p-phenetidine = mass / molar mass

Moles of p-phenetidine = 6.48 g / 137.18 g/mol

Moles of p-phenetidine = 0.0472 mol

Since p-phenetidine is the limiting reagent, the moles of acetophenetidin produced should be equal to the moles of p-phenetidine used.

The theoretical yield of acetophenetidin can be calculated using the stoichiometry of the reaction:

Theoretical yield = Moles of p-phenetidine × (molar mass of acetophenetidin / molar mass of p-phenetidine)

Theoretical yield = 0.0472 mol × (179.22 g/mol / 137.18 g/mol)

Theoretical yield = 0.0616 mol

Now we can calculate the percent yield:

Percent yield = (actual yield / theoretical yield) × 100

Percent yield = (5.72 g / (0.0616 mol × 179.22 g/mol)) × 100

Percent yield = (5.72 g / 11.2512 g) × 100

Percent yield = 50.8%

Therefore, the percent yield for this reaction is 50.8%.

Learn more about  reaction here

https://brainly.com/question/16737295

#SPJ11

Approximately 777.6 grams of water is needed to make 7.2 moles of glucose based on the balanced equation.

The balanced equation provided is:

6CO2 + 6H2O -> C6H12O6 + 6O2

From the equation, we can see that for every 6 moles of water (H2O), 1 mole of glucose (C6H12O6) is produced. Therefore, we need to determine the amount of water required to produce 7.2 moles of glucose.

The mole ratio between water and glucose is 6:1. This means that for every 6 moles of water, we obtain 1 mole of glucose. To find the amount of water needed for 7.2 moles of glucose, we set up a proportion using the mole ratio:

(6 moles H2O / 1 mole glucose) = (x moles H2O / 7.2 moles glucose)

Solving for x, we can cross-multiply:

6 moles H2O * 7.2 moles glucose = x moles H2O * 1 mole glucose

43.2 moles H2O = x moles H2O

Therefore, we need 43.2 moles of water to produce 7.2 moles of glucose.

To convert moles of water to grams, we need to know the molar mass of water, which is approximately 18 g/mol. Using the molar mass, we can calculate the mass of water needed:

Mass of water = moles of water * molar mass of water

Mass of water = 43.2 moles * 18 g/mol

Mass of water = 777.6 g

Therefore, approximately 777.6 grams of water is needed to make 7.2 moles of glucose based on the balanced equation.

for more such question on glucose visit

https://brainly.com/question/397060

#SPJ8

Answer:

No.

Explanation:

When mass is destroyed, it has to have been transformed into something else. Otherwise that would violate the Law of Conversion of Mass. In this case, the wood converted some of its mass in chemical energy to thermal (or heat) energy.

Answer:

three

Explanation:

Every element in the boron group has three electrons in its outermost shell (so-called valence electrons), and for each element there is a sharp jump in the amount of energy required to remove the fourth electron, reflecting the fact that this electron must be removed from an inner shell.

The net ionic equation for the given condition is: -

MnO4 (aq) + 5Fe2+ (aq) + 8H30+ (aq)— Mn2+ (aq) + 5Fe3+ (aq) + 12H2O(a)

A balanced chemical equation is the equation where all the number of reactant and products are equalized based on the number of moles and concentration.

        According to the given condition, we have 0.1569 Molar permanganate solution titrated.

    For 1L of solution we have 0.1569 molar permanganate,

Therefore,

1000ml = 0.1569m

19.53ml = 19.53 x 0.1569 / 1000

              = 0.00306 moles. = 3.06 x 10^-3 moles.

The ionic equation says that 1 mol of MnO4- reacts with 5 moles of Fe2+ so, 3.06 x 10^-3 reacts with 19.53 ml to give,

19.53ml = 3.06 x 10^-3

30.00 ml = 3.06 x 10^-3 x 30.00/ 19.53

               = 4.700 x 10^-3 moles.

This quantity of moles are in the solution required, in the volume i was given (30.00 ml). To get the concentration I have to calculate the moles in 1L.

learn more about concentration at,

https://brainly.com/question/13811573

#SPJ4

The neutralization reaction between hydrobromic acid (HBr) and potassium hydroxide (KOH) can be completed and balanced as follows:

HBr(aq) + KOH(aq) → KBr(aq) + H2O(l)

The products of this reaction are potassium bromide (KBr) and water (H2O).

To write the net ionic equation, we exclude the spectator ions, which are the ions that appear on both sides of the equation unchanged. In this case, the potassium ion (K+) is a spectator ion because it appears on both sides. Therefore, the net ionic equation is:

H+(aq) + OH-(aq) → H2O(l)

In the net ionic equation, the hydrogen ion (H+) from the acid and the hydroxide ion (OH-) from the base combine to form water (H2O).

To know more about hydrobromic refer here

https://brainly.com/question/30459979#

#SPJ11

Explanation:

Malleability refers to the flexibility of something , e.g bending

Ductility refers to how long copper wire can be stretched

Answer:

if i consider this reaction

Fe2O3+ 3CO---》2Fe+ 3CO2

so let's calculate first moles of Fe2O3 i.e. = 256/159.69= 1.6 moles

So the one moles of Fe2O3 is forming three moles of CO2

hence 1.6 moles will form 4.8 moles of CO2

one mole of CO2 is 44 g so 4.8 moles of Co2 is 44×4.8= 211.2 g

so the conclusion is 211.2 g of CO2 can be produced from 256 g Fe2O3!!

i d k it's right or wrong but i tried my best :)

The purpose of running a mixed melting point is to determine the identity or purity of an unknown substance.

The purpose of running a mixed melting point is to confirm the identity and purity of a solid compound. It works by comparing the melting point of a known pure substance with that of a mixture of the pure substance and the unknown compound.

Step-by-step explanation:

1. Prepare two samples: one of the pure known substance and the other of a mixture of the known substance and the unknown compound.
2. Place each sample in a capillary tube.
3. Insert the capillary tubes into a melting point apparatus, which gradually increases temperature.
4. Observe and record the melting points of both samples.
5. Compare the melting points: if they are identical, the unknown compound is likely the same as the known substance. If the mixed melting point is lower or broader than the known substance's melting point, it indicates the presence of impurities or that the unknown compound is different from the known substance.

In summary, the purpose of a mixed melting point is to verify the identity and purity of a compound, and it works by comparing melting points of a pure substance and a mixture of the pure substance and the unknown compound.

Learn more about capillary tube here: brainly.com/question/13740803

#SPJ11

The temperature of the sample of CO² gas is 87.41 Kelvin.

Combined gas law put together both Boyle's Law, Charles's Law, and Gay-Lussac's Law. It states that "the ratio of the product of volume and pressure and the absolute temperature of a gas is equal to a constant.

It is expressed as;

P₁V₁/T₁ = P₂V₂/T₂

At STP (standard temperature and pressure), the temperature is 273.15 K and the pressure is 1 atm.

Therefore, we can use the combined gas law to solve for the final temperature:

P₁V₁/T₁ = P₂V₂/T₂

Where P₁ = 1 atm, V₁ = 0.50 L, T₁ = 273.15 K, P₂ = 1.6 atm, V₂ = 0.10 L, and we are solving for T₂.

Substituting the values and solving for T2, we get:

T₂ = (P₂V₂T₁) / (P₁V₁)

T₂ = ( 1.6 atm × 0.10 L × 273.15 K) / (1 atm × 0.50 L)

T₂ = 87.41 K

Therefore, the temperature of the sample is 87.41 K.

Learn more about the combined gas law here: brainly.com/question/25944795

#SPJ1

Answer:

2 moles of nitrogen, 8 moles of hydrogen, 1 mole of sulfur

Explanation: i took the test and got it right

The number of moles for each element in one mole of (NH₄)₂S are:

d. 2 moles of nitrogen, 8 moles of hydrogen, 1 mole of sulfur

The number of moles can be identified by dividing the given mass by molar mass.

In one mole of (NH₄)₂S there are moles of each participating element i.e. nitrogen, oxygen, hydrogen, and sulfur.

In this molecule, there are 2 moles of nitrogen, 8 moles of hydrogen, and one mole of sulfur.

Thus, option d is correct.

Find more information about One mole here:

brainly.com/question/1358482

The diagram represents a nuclear fission reaction where a Uranium-235 nucleus absorbs a neutron, becomes unstable and splits into two fragments releasing energy and neutrons.

Nuclear fission is the process of splitting an atomic nucleus into two or more smaller nuclei with the release of energy, while nuclear fusion is the process of combining two or more atomic nuclei into a larger nucleus with the release of energy.

In a nuclear fission reaction, energy is released due to the conversion of a small amount of mass into a large amount of energy, in accordance with Einstein's famous equation E=mc^2. The release of energy occurs when the Uranium-235 nucleus splits into two fragments, releasing neutrons and gamma radiation in the process.

Learn more about nuclear fission here:

https://brainly.com/question/29141330

#SPJ1

A pressure of 0.200 atm is same as 20265 Pa when converted in pascals, similarly it is equivalent to 202.65 mbar, 20.265 kPa, 152 mmHg, 2.907 psi and 152 Torr.

Given the pressure = 0.200atm

Atmospheric pressure, also known as barometric pressure, is the pressure exerted by the weight of air in the atmosphere of Earth. It is measured by a barometer in units of millibars (mb) or hectopascals (hPa).

The different units of atmosphere are Pascals (Pa), Bars (bar), Millibars (mbar), Atmospheres (atm), Millimeters of Mercury (mmHg), Kilopascals (kPa), Torr (Torr) and Pounds per Square Inch (psi)

The pressure of 0.200 atm can be converted to different units by multiplying it with the conversion factors of the respective units.

Pascal (Pa): 0.200 atm x (\(1.01325 * 10^5 Pa/atm\)) = 20265 Pa

Millibar (mbar): 0.200 atm x (1013.25 mbar/atm) = 202.65 mbar

Kilopascal (kPa): 0.200 atm x (101.325 kPa/atm) = 20.265 kPa

Millimeter of Mercury (mmHg): 0.200 atm x (760 mmHg/atm) = 152 mmHg

Pounds per Square Inch (psi): 0.20 atm x 14.535 psi/atm = 2.907 psi

Bars (bar): 0.200 atm × 1.01325 bar/atm = 0.206650 bar

Torr (Torr): 0.20 atm x 760 Torr/atm = 152 Torr

To learn more about pressure click here https://brainly.com/question/18431008

#SPJ1

Answer:

bends and slides under one another

Explanation:

"Where two tectonic plates meet at a subduction zone, one bends and slides underneath the other, curving down into the mantle."

Answer:

Where two tectonic plates meet at a subduction zone, one bends and slides underneath the other, curving down into the mantle. (The mantle is the hotter layer under the crust.) Tectonic plates can transport both continental crust and oceanic crust, or they may be made of only one kind of crust.

A food chain are interconnected in the sense that it shows a single pathway from the producers to the consumers and  the way energy flows in this pathway.

This refers to a linear sequence of organisms where nutrients and energy is moved from one organism to the other. This occurs when one organism consumes another organism.

The food chain starts with the producer organism, follows the chain and ends with the decomposer organism. m for survival. For example Grass (Producer) —–Goat (Primary Consumer) —– Man (Secondary consumer).

Learn more about food chain on

https://brainly.com/question/1807825

#SPJ1

Hope you could get an idea from here.

Doubt clarification - use comment section.

Answer:

1. Dissolving powder in milk - Chemical

  - It is chemical because the milk has changed on a molecular level

2. Toasting bread - Chemical

   - It is chemical because adding heat to the bread cooks it, therefore

     changing it on a molecular level

3. Melting cheese - Physical

   - It is physical because the physical appearance was the only change

4. Slicing apples or bannanas - Physical

   - It is physical because the physical appearance was the only change

5. Frying an egg - Chemical

   - It is chemical because new particles were formed

6. Milk souring - Chemical

   -  It is chemical because it is forming a new product (lactic acid)

Explanation:

Physical Change occurs when the particles of a substance become rearranged, but do not change into different particles.  

Chemical change occurs when a new substance is formed. This process is irreversable.

Answer:

give the preson above brainly bc there right

Explanation:

Assuming that the values for Lt and Dm are known, we can calculate the length of column necessary to separate two species with a resolution of 1.5.

To calculate the resolution (Rs) for species B and C, we use the formula:
Rs = 2*(tR2 - tR1)/(W1 + W2)
where tR is the retention time and W is the peak width at the baseline.
Assuming that the retention times and peak widths are known, we can calculate the resolution for species B and C.
For the selectivity factor (α), we use the formula:
α = k2/k1
where k is the capacity factor, which is equal to (tR - t0)/t0, where t0 is the void time.
Assuming that the capacity factors are known, we can calculate the selectivity factor for species B and C.
Finally, to calculate the length of column necessary to separate two species with a resolution of 1.5, we use the equation:
N = 16(Rs - 1)/(α - 1)^2
where N is the number of theoretical plates and Rs and α are the resolution and selectivity factor, respectively.
Assuming that the values for Rs and α are known, we can calculate the number of theoretical plates and then use the equation:
L = N*Lt/Dm
where L is the column length, Lt is the retention time, and Dm is the diffusion coefficient.
Assuming that the values for Lt and Dm are known, we can calculate the length of column necessary to separate two species with a resolution of 1.5.

learn more about resolution here

https://brainly.com/question/30545863

#SPJ11

Answer:

Various compounds made of different forces between molecules

Explanation:

In an experiment, the independent variable is the variable that is changed or manipulated by the experimenter in order to effect a measurable response.

According to this question, a student compares the boiling point of substances having different intermolecular forces. This means that the student uses different substances with different intermolecular forces and measures the boiling point of each, which depends on the intermolecular forced in them. Hence, the independent variable in this experiment is the VARIOUS COMPOUNDS MADE OF DIFFERENT FORCES BETWEEN MOLECULES.

Answer: The pressure of the hydrogen in the gas-collecting tube is 721.3 mm Hg

Explanation:

According to Dalton's law, the total pressure is the sum of individual pressures.

\(p_{total}=p_{H_2O}+p_{H_2}\)

Given : \(p_{total}\) =total pressure of gases = 741.1 mm Hg

\(p_{H_2O}\) = partial pressure of water = 19.8 mm Hg

\(p_{H_2}\) = partial pressure of hydrogen = ?

putting in the values we get:

\(741.1 mm Hg=19.8mmHg+p_{H_2}\)  

\(p_{H_2}=721.3mm Hg\)

Thus  the pressure of the hydrogen in the gas-collecting tube is 721.3 mm Hg

According to the Dalton Law in a blend of non-reacting gases, the entire pressure will be equivalent to the total of partial pressures of the individual gases.

The pressure of H₂ gas collected in the tube will be 721.3 mm Hg.

This can be calculated by:

Dalton's formula:

\(\text{p}_{\text{total}} & = \text{p}\text{H}_{2} \text{O} + \text{p} \text{H}_{2}\)

Given :  

Now using the formula we will calculate:

\(\text{741.1 mm Hg} & = \text{19.8 mm Hg} + \text{p} \text{H}_{2}\)

\(721.3 \;\text {mm Hg} = \text{p} \text{H}_{2}\)

Therefore, the pressure of the hydrogen in the tube is 721.3 mm Hg.

To learn more about Dalton Law follow the link:

https://brainly.com/question/14119417