To a 25.00 mL volumetric flask, a lab technician adds a 0.225 g sample of a weak monoprotic acid, HA , and dilutes to the mark with distilled water. The technician then titrates this weak acid solution with 0.0849 M KOH . She reaches the endpoint after adding 42.35 mL of the KOH solution. Determine the number of moles of the weak acid in the solution.

Answers

Answer 1

The number of moles of the weak acid in the solution is 0.00359

Calculation:

1. The number of mole of KOH in the solution:

Given:

Molarity of KOH = 0.0849 M

Volume = 42.35 mL = 42.35 / 1000 = 0.04235 L

Mole of KOH = Mole = Molarity x Volume

                      = 0.0849 ×  0.04235

                      = 0.00359 mole

2. The number of mole of a weak acid, HA:  

Balanced equation:

HA + KOH → KA + H₂O

From the above equation, A mole of HA and a mole of KOH react together. Therefore,

0.00359 moles of HA will also react with 0.00359 moles of KOH.

0.00359  moles of base use = 1/1 x 0.00359 = 0.00359 moles of HA

Thus, there are 0.00359 moles of a weak acid in the solution.

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Related Questions

Suppose a aqueous solution of phosphoric acid () is prepared. Calculate the equilibrium molarity of . You'll find information on the properties of phosphoric acid in the ALEKS Data resource.

Answers

The equilibrium molarity HPO²₄- = 6.2 x 10⁻⁸M See the explanation below.

What is Equilibrium Molarity?

The molar concentration of a certain species in a solution is known as equilibrium molarity.

What is the calculation showing the above answer?

The initial concentration H₃PO₄ = 0.31 M

Kₐ₁ = 6.92 x 10⁻³ (See Image 1 attached)

Kₐ₁ = [H⁺][tex]_{eq}[/tex][H₂PO₄-][tex]_{eq}[/tex] / [H₃PO₄][tex]_{eq}[/tex]

6.92⁻³ x 10 = [(x) * (x)] / (0.31 M - x)

Solving for x, x = 0.043 M

[H+] = x = 0.043 M

[H₂PO₄-] = x = 0.043 M 0.0429805

Kₐ₂ = 6.2 x 10⁻⁸

See the second attached table

Kₐ₂ = [H+][tex]_{eq}[/tex] [HPO₄²-]eq / [H₂PO₄-]eq

6.2 x 10⁻⁸ = [(0.043 M + x) * (x)] / (0.043 M - x)

Solving for x, x = 6.2 x 10⁻⁸ M

[H₂PO₄-]eq = x = 6.2 x 10⁻⁸ M

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No attempt was made to test sodium with hydrochloric
acid. Why not?

Answers

Answer:

the reaction is violent and quick

Explanation:

Write the formula and determine the percent by mass of the salt in barium hydroxide octahydrate *


(show work)

Answers

Answer:

315.51g/mol

Explanation:

137(33 + (16.00 + 1.01) 2 + 8 [1.01 (2) + 16.00] = 315.51g/mol

what is the name of this branched alkane?

Answers

Answer:

Explanation:

3-methyl pentane.

Answer:

the answer is methyl pentane

chemical change grade 10 mind map ​

Answers

Chemical change: A chemical reaction is the change of one chemical substance into another chemical substance. For instance: The rusting of iron, the curdling of milk, the digestion of food, breathing, etc.

What is a chemical reaction?

A chemical reaction results in a chemical change because a new material has entirely different properties from the original substance. In a chemical reaction, atoms rearrange themselves.Reactants are the chemicals that participate in a chemical reaction.Products are the new compounds created as a result of a chemical process.  An illustration of a chemical reaction is burning magnesium in the air to produce magnesium oxide.2Mg(s) + O2(g) △→ 2MgO(s)The magnesium ribbon is cleaned with sandpaper before being burned in the air. This cleans the magnesium ribbon's surface of the basic magnesium carbonate protecting coating.Reactant: Materials that participate in a chemical reaction are referred to as reactants. Mg and O2, as an example.A product is a newly created substance that results from a chemical reaction. Example: MgO.

A chemical reaction is the change of one chemical substance into another chemical substance.

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Chemical  change is the change  chemical substance is transformed into another chemical substance.It is irreversible in  nature , for example Reaction of medicine in body , milk to curd etc.

What is the difference between chemical and  Physical change?

1)Physical change temporary or reversible in nature but chemical change is irreversible in nature

2)In physical change there no new product is formed but in chemical change there formation of new product takes .

3) Physical change is change sin shape ,size or state for example freezing of water , melting of wax , and example of  Chemical change are Burning of  coal, digestion of food

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Thermal expansion occurs when particles of matter move farther apart as temperature increase. True or false ?

Answers

Answer:

true

Explanation:

Which of the following is NOT a property of metals?

A - shiny
B - ductile
C - can be solids, liquids, or gases
D - malleable

Answers

Answer:

C - can be solids, liquids, or gases

Explanation:

What is the reason why the fermentation products acetate and hydrogen gas (H2) are never abundant in aerobic soils and sediments

Answers

Acetate and hydrogen gas (H2) is never abundant in aerobic soils and sediments because they are tiny, highly reduced molecules that many bacteria that breathe oxygen and nitrates quickly absorb to use as fuel for energy generation. 

Why are acetate and hydrogen gas not abundant in aerobic soils and sediments?

Hydrogen is a substrate for methanogenic archaea and, along with acetate, one of the most significant intermediates in the methanogenic breakdown of organic materials. Numerous methanogenic environments exhibit contributions of H₂ to CH₄ production that are both significantly lower and significantly higher than is considered usual. H₂ is rapidly converted in methanogenic settings due to the simultaneous generation by fermenting and syntrophic bacteria and consumption by methanogenic archaea.

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explain why dilute trioxosulphate vi acid is not used to prepare carbon 4 oxide from calcium
trioxocarbonate 4​

Answers

Answer:

H2SO4 cannot be used with CaCO3 to produce CO2 gas

Explanation:

Because it does not dissolve in water- it forms a barrier on the surface of the unreacted CaCO3 which prevents any further reaction. A small volume CO2 is produced, this stops in short time.

I hope this helps :)

Guys pleaseeeee help:
- Which element is a member of the alkaline earth metals and has 12 neutrons?
- A burnt piece of toast is covered in this element. It is the fourth most abundant element and makes up many living things.
- Which element is an inert gas found in group VIII that produces a red glow in lights?

Answers

Answer:

Carbon- A burnt piece of toast is covered in this element. It is the fourth most abundant element and makes up many living things.

Magnesium- Which element is a member of the alkaline earth metals and has 12 neutrons?

Neon- Which element is an inert gas found in group VIII that produces a red glow in lights?

A text book is on a desk. If the book weighs 14 N and the area of the book is 0.60 m 2 , what pressure is the book exerting on the desk?

Answers

Answer:

Explanation:

Pressure = Force / Area

F = 14 N

Area = 0.60 m^2

Pressure = 14/0.60

Pressure = 23.3 N

If you are worried about significant digits, the answer is 23

please help me out i will give you brainlist. 0.500 is wrong

Answers

Answer:  b) 0.250 mol

============================================

Work Shown:

Using the periodic table, we see that

1 mole of carbon = 12 grams1 mole of oxygen = 16 grams

These are approximations and these values are often found underneath the atomic symbol. For example, the atomic weight listed under carbon is roughly 12.011 grams. I'm rounding to 2 sig figs in those numbers listed above.

So 1 mole of CO2 is approximately 12+2*16 = 44 grams. The 2 is there since we have 2 oxygens attached to the carbon atom.

-------------------

Since 1 mole of CO2 is 44 grams, we can use that to convert from grams to moles.

11.0 grams of CO2 = (11.0 grams)*(1 mol/44 g) = (11.0/44) mol = 0.250 mol of CO2

In short,

11.0 grams of CO2 = 0.250 mol of CO2

This is approximate.

We don't need to use any of the information in the table.

Answer:

.250

Explanation:

The yellow light given off by a sodium vapor lamp has a wavelength of 589nm. What is the frequency of this radiation? Please show all work.

Answers

Answer:

5.09 x 10⁶ s⁻¹ = 5.09 x 10⁶ Hz

Explanation:

The relation between frequency (ν) and wavelength (λ) is given by:

λ = c/ν

where c is the speed of light (2.998 m/s) and it is a constant.

So, we first convert the wavelength from nanometers (nm) to meters (m) (1 nm = 1 x 10⁻⁹):

λ= 589 nm x (10⁻⁹ nm/1 m) = 5.89 x 10⁻⁷ m

Then, we calculate the frequency from the equation:

λ = c/ν ⇒ ν = c/λ = (2.998 m/s)/(5.89 x 10⁻⁷ m) = 5.09 x 10⁶s⁻¹ = 5.09 x 10⁶ Hz

PLEASE ANSWER QUICK... WILL GIVE BRAINLIEST

The relative humidity is 100%, and the temperature is hot. In a few sentences, explain how the weather would change if the temperature drops and becomes cool.

Answers

Answer:

Humdity would decrease hence temprature would do the same, hence tundra are called deserts at times.

Explanation:

If you keep on decreasing the temperature without changing the air's moisture content significantly, eventually you'll reach 100 percent relative humidity, and then water vapor will start to condense to form dew.

What happens when humidity is at 100% and the temperature drops?

Dew Point. When the relative humidity reaches 100 percent, dew forms. Dew point refers to the temperature at which air reaches saturation by water molecules. Warmer air can hold more water molecules, and as that warm air cools, it loses water vapor in the form of condensation.

What happens when it reaches 100% relative humidity?

When relative humidity reaches 100 percent or is saturated, moisture will condense, meaning the water vapor changes to liquid-vapor. Thus, the saturation level of air is related to the air's temperature.

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how many molecules are there in 1.5 mol of methane

Answers

Answer: A mole of something means that there are 6.02 X 10^23 of that something. So, a mole of methane molecules is 6.02 X 10^23 methane molecules. So, 1.5 moles of methane will contain 1.5*(6.02 X 10^23) = 9.0 X 10^23 methane molecules

Explanation:

an example of xenon (Xe)

Answers

Answer: i am not sure what you mean but here are some product of xenon stroboscopic lamps, photographic flash lamps, high-intensive arc-lamps for motion picture projection, some lamps used for deep-sea observation, bactericidal lamps, sunbed lamps and high-pressure arc all use this gas. In fact, you probably see xenon lamps on a regular basis and if you want compounds : Xe2F2, XeF4, XeO3, XeF6....

Explanation:

difference between solute and solvent​

Answers

When one substance dissolves into another, a solution is formed.  A solution is a homogeneous mixture consisting of a solute dissolved into a solvent .  The solute is the substance that is being dissolved, while the solvent is the dissolving medium.  Solutions can be formed with many different types and forms of solutes and solvents.

Explanation:

solute are substance that dissolve in solvent

solvent are substance that dissolve solute

Carbon dioxide and water are produced when ethanol, C2H5OH, is burned in oxygen. The number of moles of CO2 that is produced when burning 6.0 mol of ethanol is

Answers

The number of moles of CO₂ that is produced when burning 6.0 mol of ethanol is 12 mol.

What is Balanced Chemical Equation ?

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

Now we have to write the balanced equation

C₂H₅OH + 3O₂ → 2CO₂ + 3H₂O

We can see that every 1 mole of ethanol we will get 2 mole of CO₂.

So 6.0 mol of ethanol we will get = 6.0 × 2.0

                                                       = 12 mol of CO₂

Thus from the above conclusion we can say that The number of moles of CO₂ that is produced when burning 6.0 mol of ethanol is 12 mol.

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changing the number of _______ makes an atom stable or unstable and creates different isotopes of the same element with a different ______ (pick two that best fits.)
a.) atomic mass
b.) atomic number
c.) protons
d.)neutrons
e.)electrons
f.) ion
g.)neutral

Answers

changing the number of NEUTRONS makes an atom stable or unstable and creates different isotopes of the same element with a different ATOMIC MASS

The neutrons are the neutral sub-atomic particles present in the nucleus. The variation in the number of neutrons produces isotopes that have different atomic mass. Thus, options 1. d and 2. a are correct.

What is an isotope?

An isotope is said to be an atom of an element that have a different atomic mass but the same atomic number due to the variation in the neutrons in the nucleus. The neutrons have a neutral charge that makes the atom stable.

When a neutron is added or lost it makes the nucleus of the atom unstable leading to radioactive decay. The isotopes have the same constant number of protons in their nucleus.

The atomic number of the atom remains the same due to the stable proton number but varies the atomic mass due to the change in the number of neutrons.

Therefore, options d and a. neutrons and atomic mass are the correct blanks.

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SCIENCE
Does combustion need oxygen?

A. Yes
B. No

Answers

Answer: a. Yes

Explanation:

Answer:

A. yes

Explanation:

In order to burn this fuel, oxygen is needed, as it is with any fire. The waste products from the combustion process are water and carbon dioxide. Thus, we breathe because oxygen is needed to burn the fuel (sugars and fatty acids) in our cells to produce energy The air we breathe contains about 21% oxygen.

how many bananas are equal to 7.50 moles of bananas?​

Answers

Answer:

4.52×10^24

Explanation:

N = n × Na

where; N = no. of bananas

n = no. of moles

Na = Avogadro's constant

Which is 6.02×10^23

N = 7.5 × 6.02×10^23

N =4.515×10^24

Which federal agency makes sure federal wildlife laws are followed?

US Forest Service
US Fish and Wildlife Service
Bureau of Land Management
National Park Service

Answers

Answer:

us fish and wildlife service

Explanation:

the 2nd choice

Answer:

US Fish and Wildlife Service

Describe the energy of the products in comparison to the energy the atoms had when the were wandering around the room free.

Answers

Answer: The atoms of the solid products are tightly packed whereas those in gas are loose.

Explanation:

Atoms in the solid structure are linked to each other by strong force of attraction and they collectively form an three-dimensional structure. The binding of the atoms form the shape of the solid product. The gas exhibit free atoms in it. The atoms are not linked to one another by strong force of attraction. The atoms as a part of gas have higher energy as those present in the solid products. So, the atoms of the gas wander freely as compared to those in the solid products.

Plzzzzz I need help ASAP

Answers

Answer:

i) B, ii) A, iii) C

Explanation:

give me brainliest

(iii) Observe the following diagram and answer the following questions :
X Х
Y
(A) Identify elements X and Y.
(B) Do these elements belong to the same group?
(C) Which element is more electropositive in nature? Why?​

Answers

Ghhfcnjjakwhwbebsiiwuehebsjudyehebwklwiwgehebwkwkkehehrbwkeiehegenkeiehehenekeurhrh

Which statements describe band theory? Check all that apply.

Electrons all have approximately the same energy.

Electrons move among orbitals of different energies.

Electrons move freely among atoms (delocalized).

Answers

Answer:

b c

Explanation:

right

Answer:

it was A C for me

Explanation:

Al +CI = Al CI3
how do i solve this

Answers

There has to be a small 2 at the bottom right of Cl (sorry I cannot write 2 under Cl as a small number, but I hope you understand what I mean):

Al + Cl2 —> AlCl3

If you are requesting for it to be balanced, it would be:

2 Al + 3 Cl2 —> 2 AlCl3

Think about a synthetic material that you use every day. How
could that material be improved to better fit its function?

Answers

explanation: Synthetic fiber or synthetic fibre (in British English; see spelling differences) are fibers made by humans through chemical synthesis, as opposed to natural fibers that are directly derived from living organisms. They are the result of extensive research by scientists to improve upon naturally occurring animal and plant fibers. In general, synthetic fibers are created by extruding fiber-forming materials through spinnerets, forming a fiber. These are called synthetic or artificial fibers. Synthetic fibers are created by a process known as polymerization, which involves combining monomers to make a long chain or polymer. The word polymer comes from a Greek prefix "poly" which means "many" and suffix "mer" which means "single units". (Note: each single unit of a polymer is called a monomer). There are two types of polymerization: linear polymerization and cross-linked polymerization.

1.0 mol of ethanol and 1.0 mol of acetic acid are dissolved in water and kept at 100 °C. The volume of the solution is 250 mL. At equilibrium, 0.25 mol of acetic acid has been consumed in producing ethyl acetate. Calculate Kc at 100 °C for the reaction C2H5OH(aq) + CH3CO2H(aq) CH3CO2C2H5(aq) + H2O(l)

Answers

Answer:

Kc = 0.333

Explanation:

First of all we state the equilibrium reaction:

C₂H₅OH(aq) + CH₃CO₂H(aq)  ⇄  CH₃CO₂C₂H₅(aq) + H₂O(l)

Initially we start with 1 mol of alcohol and 1 mol of acid. After the reaction goes complete, 0.25 moles of acid have been consumed. As ratio is 1:1, we also consumed 0.25 moles of alcohol. Then, in the product side we finally produced 0.25 moles of water and 0.25 moles of ethyl acetate.

How many moles are available in the reactant side, after the equilibrium?

1 mol - 0.25 moles (that have been reacted) = 0.75 moles.

To determine Kc, we need molar concentrations, so let's see M in products and reactants:

0.75 mol / 0.25 L = 3 M

0.25 mol / 0.25 L = 1 M

We needed to convert 0.250 mL to L → 0.250 mL . 1L/ 1000mL = 0.250 L

Let's determine expression for Kc:

Kc = [H₂O] . [CH₃CO₂C₂H₅]  / [C₂H₅OH] . [CH₃CO₂H]

1 . 1 / 3 . 3 = 1/9 → 0.333

The enthalpy of fusion for Al is 10.7 kJ/mol. What is the energy change when 30.8 g of Al solidifies at 660°C?

Answers

The enthalpy of fusion for Al is 10.7 kJ/mol. -12.2 kJ is the energy change when 30.8 g of Al solidifies at 660°C.

What is Enthalpy of Fusion ?

The amount of energy needed to change 1 mole of substance under state change at constant temperature and pressure is called enthalpy of fusion. It is also known as Latent heat of fusion. Unit of enthalpy of fusion is kJ/mol.

How to find the change in energy ?

To find the change in energy use this expression:

q = n ΔH

where

q = Energy change

n = number of moles

ΔH = Molar enthalpy

Number of moles (n) = [tex]\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

                                  = [tex]\frac{30.8\ g}{26.98\ \text{g/mol}}[/tex]

                                  = 1.141 mol

Now put the values in above formula we get

q = - n ΔH                    [Negative sign is used because Al solidifies here]

  =  - (1.141 mol × 10.7 kJ/mol)

  = -12.2 kJ

Thus from the above conclusion we can say that The enthalpy of fusion for Al is 10.7 kJ/mol. -12.2 kJ is the energy change when 30.8 g of Al solidifies at 660°C.

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Even as late as the 1860s, the basic formations for soldiers were O a. column, line, and square O b.oblique, angle, and echelon O c. paraphrase, quadrant, and epsilon A certain molecule can be treated as having only a double degenerate state using at 360 cm' above the non-degenerate ground state. The approximate temp. (k) at which 15% of the molecules will be in the upper state is: (a) 500 (b) 150 (C)200 (d) 300 in the ground state of hydrogen, the uncertainty in the position of the electron is roughly 0.10 nm. if the speed of the electron is approximately the same as the uncertainty in its speed, about how fast is it moving? m/s Helium gas with a volume of 2.90 L , under a pressure of 0.160 atm and at a temperature of 45.0 C, is warmed until both pressure and volume are doubled.What is the final temperature?How many grams of helium are there? The molar mass of helium is 4.00 g/mol. . Using the Bohr model, calculate the energy of a photon emitted when an electron in a Li2+ ion moves from an orbit with n=3 to the orbit with n=2.Group of answer choicesA. 7.8261038 JB. 9.07910-19 JC. 3.268510-18 JD. 2.72410-18 J 100 Points! Geometry question. Photo attached. Please show as much work as possible. Thank you! describe the mechanism of crack propagation for both ductile and brittle modes of fracture What are the factors affecting the shrinkage and creep? who is most likely to suffer from low self-esteem? social psychology Sean A = < - 7, 5 ] U [10, 18 >, B = [ - 2, 8 > U < 13, 23 ]C = < 1, 15>.Hallar: (A B ) - C experiments suggest that practicing parts of a discrete task in isolation__________. T/F. a series of studies show that environmental stressors, particularly severe stressors (e.g., loss of a significant relationship), can worsen the symptoms of bipolar disorder. What is defined as the subcontracting of services and operations to an outside vendor? Multiple choice question. Outsourcing. Benchmarking. Decentralization. in the context of values that characterize western cultures, people who value the original article or a faithful reproduction focus on a(n) ________ license allows a person to post his or her work on the internet and allows others to copy and distribute it. A 90 elbow in a horizontal pipe is used to direct water flow upward at a rate m of 40 kg/s. The diameter of the entire elbow is 10 cm. The elbow discharges water into the atmosphere, and thus the pressure at the exit is the local atmospheric pressure. The elevation difference between the centers of the exit and the inlet of the elbow is 50 cm. The weight of the elbow and the water in it is considered to be negligible. Take the density of water to be 1000 kg/m3 and the momentum-flux correction factor to be 1. 03 at both the inlet and the outlet. Determine the gage pressure at the center of the inlet of the elbow The three-dimensional shape of a molecule depends on the number of electron groups around the central atom. Because like charges repel, the molecule adopts a shape that allows the electron groups to be as far apart as possible. Very often, a two-dimensional dot structure does not accurately represent what the molecule would look like in three dimensions.Match each two-dimensional structure to its correct three-dimensional description. 1 tbsp. all- purpose flour ( for thickening)a. cornsatrch b.1 tbsp. cream c. 2 eggs d. 1 tbsp. mayonnaise2. 2 tbsp. buttera. 2 tbsp. cooking oil c. 2 tbsp. lardb. 2 tbsp. coconut oil d. 2 tbsp. margarine3. 2/3 cup cocoaa. cup sweetened chocolate c. cup tableab. 1 cup sweetened cocoa d. 3 sq. unsweetened cocoa4. 1/4 cup bread crumbsa. cup bread c. cup cracker crumbsb. 1 cup breadings d. cup flour5. granulated sugara. brown sugar b. confectioners sugar c. honey d. molasses research shows that employees take longer to reply to voice messages than to other types of technology. T/F? Which quantum numbers must be the same for the orbitals that they designate to be degenerate in a one-electron system (such as hydrogen)?a) n, l and mlb) l and mlc) n onlyd) n and l onlye) ml only