A sample was then prepared containing 14.00 mL of coffee and 8.00 mL of 4.80 ppm Li , and diluted to a 50.00 mL total volume. The ratio of the internal standard signal to the analyte signal in the unknown sample was found to be 0.840/1.000 (Li signal/Na signal). Determine the unknown concentration of Na in the coffee sample.

Answers

Answer 1

Answer:

The right answer is "[tex][Na^+]=5.57 \ ppm[/tex]".

Explanation:

The given values are:

[tex]\frac{A_s}{A_{coffee}} =\frac{0.840}{1.000}[/tex]

According to the question,

The concentration of standard will be:

=  [tex]\frac{7.80}{50.00}\times 4.80[/tex]

=  [tex]0.156\times 4.80[/tex]

=  [tex]0.748 \ ppm[/tex]

Coffee after dilution,

⇒  [tex]\frac{A_{coffee}}{C_{coffee}} =F\times \frac{A_s}{C_s}[/tex]

or,

⇒  [tex]C_{coffee}=\frac{A_{coffee}}{A_s}\times \frac{C_s}{F}[/tex]

On substituting the values, we get

⇒               [tex]=\frac{1.000}{0.840}\times \frac{0.748}{1.68}[/tex]

⇒               [tex]=1.191\times 1.3104[/tex]

⇒               [tex]=1.561 \ ppm[/tex]

hence,

In unknown sample, the concentration of coffee will be:

=  [tex]1.561\times \frac{50}{14}[/tex]

=  [tex]\frac{78.05}{14}[/tex]

=  [tex]5.57 \ ppm[/tex]


Related Questions

Potassium hydrogen phthalate is a solid, monoprotic acid frequently used in the laboratory as a primary standard. It has the unwieldy formula of KHC8H4O4. This is often written in shorthand notation as KHP. If 31.0 mL of a barium hydroxide solution are needed to neutralize 1.37 grams of KHP, what is the molarity of the barium hydroxide solution

Answers

Answer:

0.1082M of Barium Hydroxide

Explanation:

KHP reacts with Ba(OH)2 as follows:

2KHP + Ba(OH)2 → 2H2O + Ba²⁺ + 2K⁺ + 2P²⁻

Where 2 moles of KHP reacts per mole of barium hydroxide

To solve this question we must find the moles of KHP in 1.37g. With these moles and the reaction we can find the moles of Ba(OH)2 and its molarity using the volume of the solution (31.0mL = 0.0310L) as follows:

Moles KHP -Molar mass: 204.22g/mol-

1.37g * (1mol / 204.22g) = 0.006708 moles KHP

Moles Ba(OH)2:

0.006708 moles KHP * (1mol Ba(OH)2 / 2mol KHP) =

0.003354 moles Ba(OH)2

Molarity:

0.003354 moles Ba(OH)2 / 0.0310L =

0.1082M of Barium Hydroxide

1st law of motion law of inertia in toy story 2

Answers

Answer:Law of inertia, also called Newton's first law, postulate in physics that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force
If the forces are balanced , the object will make no movement. Enjoy :)

What is the percent by mass of magnesium in a 1000 g sample of ocean water (solution) that has 1.36 g of magnesium ions?

Answers

Answer:

So the percentage mass of Magnesium in ocean water is 0.13%.

Explanation:

brainliest pls

to the nearest gram, what is the mass of of one spoonfull of sugar? g

Answers

Answer:

the mass of one spoonful of sugar to nearest gram is 10g

What is the name of Na

Answers

sodium
mdmsjdkskdkskdjxjxjjz

What is the percent by mass of aspartame in iced tea that has 0.75 g of aspartame in 250 g of water?

Answers

Answer:0.30%

Explanation:

Which of the following contains the least amount (number) of molecules?

Group of answer choices

5.0 g O2


5.0 g H2O


5.0 g N2


5.0 g CO2

Answers

5.0 g N2
Has to be correct

Which best describes the conservation of energy as a pendulum swings in the path shown ?
A.The potential energy at point A is greater than the potential energy at point C.
B.The potential energy at point A is equal to the kinetic energy at point C.
C.The potential energy at point A is greater than the kinetic energy at point B.
D.The potential energy at point A is equal to the kinetic energy at point B.

Answers

the answer would be F


Consumers must eat other organisms
for energy. Which organisms
are consumers in this food chain?

Answers

Answer:

frog-snake+-Eagle

Explanation:

___&&&-(_(-7&&((-&(_((-_(_-8&:"&&7+_&(&_

When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II) sulfate PbSO4 is reduced to lead at the cathode and oxidized to solid lead(II) oxide PbO at the anode. Suppose a current of 17.0A is fed into a car battery for 15.0 seconds. Calculate the mass of lead deposited on the cathode of the battery. Be sure your answer has a unit symbol and the correct number of significant digits.

Answers

Answer:

0.273504 grams

Explanation:

Charge Deposited = Current ×Time

q=It

Given: I= 17.0A, t= 15.0 seconds

Q= 17×15= 255 C

Since, 1 mole contains 96500C of charge deposition

Therefore, number of moles = 255/96500 = 0.00264 moles

Moreover, since Pb changes to Pb2+,

Hence number of moles of Pb deposited = 0.00264/2

= 0.00132

Also, Molar mass of Lead = 207.2 gm/mol

Therefore, the mass of lead deposited = 0.00132×207.2 = 0.273504 grams

.

Which of these is a good conductor?
Plastic
Rubber
Wood
Metal

Answers

Metal is a good conductor of heat therefore it is the answer

A student is asked to determine the identity of an unknown metal. The student decides to use a calorimetry experiment to find the specific heat. The student will use this as a means of identifying the metal Which of the following measurements cannot made using standard laboratory equipment?
A mass of water
B temperature of metal
с heat lost by metal
D mass of metal​

Answers

Answer:

Temperture of the medal

Explanation:

Bc ik

A student needs to dilute a 0.25 M Pb(NO3)2 solution to make 73.0 mL of 0.13 M Pb(NO3)2 . Set up the calculation by placing the values with the correct units into the equation. Then, calculate the volume, in milliliters, of the 0.25 M Pb(NO3)2 solution that is needed.

Answers

Answer: Volume of 0.25 M solution is 38 ml

Explanation:   Amount of substance n remains same.

 n = c1V1 = c2V2    Solve V2 = V1c1 / c2 = 73,0 ml · 0.13 M / 0.25 M = 37.96 ml

Do frogs start their life cycle on land or water?

Answers

The answer is water because they lay eggs in water

PLEASE PLEASE HELP!!!!

Approximately what mass of potassium nitrate will eventually precipitate from a supersaturated solution containing 19 grams of the solute in 28 grams of water at 40C°?

Answers

A supersaturated solution contains more solute at a given temperature than is needed to form a saturated solution.

Increased temperature usually increases the solubility of solids in liquids.

For example, the solubility of glucose at 25 °C is 91 g/100 mL of water. The solubility at 50 °C is 244 g/100 mL of water.

If we add 100 g of glucose to 100 mL water at 25 °C, 91 g dissolve. Nine grams of solid remain on the bottom. We have a saturated solution.

Hope it helps u

Plz mrk me brainlest

What is The metric unit for volume ?

Answers

Answer:

milliliters

Explanation:

Is going to be milliliters because in the metric system of measurement,the most common unit of volume are milliliters and liters

Draw the most stable form of the major product in the reaction. 2 equivalents of an ester react with N a O C 2 H 5, followed by H 3 O plus and C 2 H 5 O H. The ester is a carbonyl bonded to a 3 carbon chain and O C H 2 C H 3.

Answers

Answer:

See answer below

Explanation:

This is a Claisen condensation. In the picture below you have the mechanism and final product.

Hope this helps

The primary forces of attraction between water molecules in H2O(l) are
1.
ionic bonds
2.
hydrogen bonds
3.
molecule-ion attractions
4.
van der Waals forces
Submit Answer

Answers

Answer:

2. Hydrogen Bonds

Explanation:

Since water is a polar covalent molecule, there is a slight negative and positive end. Due to this, the oxygen end of one water molecule gravitates towards the hydrogen molecules of another water molecule. This accounts for a bunch of weird properties of water, like why ice floats. It's also what makes water the "universal solvent," and gives all life on earth the ability to even exist.

The primary forces of attraction between water molecules in H₂O (I) are hydrogen bonds.

What kind of chemical bonding is present in water molecule?

Hydrogen bonding is present in water molecule due to which it exhibits an excellent property of adhesion to itself and to other substances.The hydrogen bonding is a result of electrostatic forces of attraction which are generated by the difference in charge between slightly positive hydrogen ions and slightly negative other ions.

In case of water,hydrogen bonds are formed  between neighboring  hydrogen and oxygen atoms  of the nearby water molecules.The attraction between water molecules itself results in a formation of a bond called as a hydrogen bond.  

It is a type of covalent bond which is formed  between hydrogen and oxygen atoms as one oxygen atom  shares its two electrons with two hydrogen atoms .The positive charge  of one hydrogen atom associates with negative charge of  oxygen atom.These are weak interactions  which are formed between a hydrogen atom each with a partial positive charge and an oxygen atom which is more electronegative than hydrogen.

To learn more about bonding in water click here:

https://brainly.com/question/5302822

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______ is the process of change from a liquid to a gas at temperatures below the boiling
point.

Answers

Answer:

evaporation is the process

Answer:

Evaporation

Explanation:

Evaporation is the process of becoming a vapor. The process of extracting moisture as by heat.

Evaporation is the process of change from a liquid to a gas at temperatures below the boiling point.

Therefore, the final answer is evaporation.

For 2-methylbutane, the AH° of vaporization is 25.22 kJ/mol and the

AS° of vaporization is 84.48 J/mol K. At 1.00 atm and 201 K, what is

the AG° of vaporization for 2-methylbutane, in kJ/mol?

Answers

Answer:

ΔG° = ΔH° - TΔS°

ΔG° = 25.22-(201 )(0.08448)

ΔG° = 8.24 kJ/mol

The standard free energy is obtained as 8.2  kJ/mol.

We know that; ΔG° = ΔH° - TΔS° where;

ΔG° = standard free energy

ΔH° = standard enthalpy

T = temperature

ΔS° = standard entropy

Hence substituting the values;

ΔG° =25.22 kJ/mol - (201 K * 84.48 J/mol K)

ΔG° = 25.22 * 10^3 J/mol -   16980.5 J/mol

ΔG° = 8.2  kJ/mol

Learn more about free energy: https://brainly.com/question/1301963

two differences between weather and climate
subject-science


Answers

Answer:

weather- rain, hail, snow, sunny, dry, etc.

climate- warm, cold, humid, dry, etc.

Explanation:

The difference if weather and climate is that climate is the way the temperature is,  whether it's warm, cold, humid, dry. While weather is the state of the atmosphere at a place and time as regards heat, dryness, sunshine, wind, rain, etc.

4. Which of the following process is NOT part of wool extraction?
(a) Shearing (b) Scouring (c) Sorting
(d) Reeling​

Answers

Answer:

Reeling is the only process not listed.

The correct answer is option D: Reeling​.

Wool is obtained from sheep. The wool so obtained is processed according to the following flow chart;

Shearing → Scouring → Sorting → Dyeing → Straightening, Rolling and Combing

Shearing is the removal of the fleece and thin skin of the sheep. Scouring is the process of washing the hair to remove grease, dust, and dirt. Sorting is the process of differentiating the fibers.

Hence, reeling is not a process in wool extraction.

https://brainly.com/question/9968125

Cómo escribir el símbolo Theta

Answers

Para escribir el símbolo theta, presione 03B8 + Alt + X.
En ingles The theta symbol

Which food is the most complete source of amino acids?

A. Bread
B. Fruit
C. Butter
D. Meat

Answers

Answer:

D.Meat

Explanation:

Meat-Most animals proteins are considered complete and high-quality.This includes red meat, poultry,and dairy products.

Amino acids are the molecules that make the protein and are essential nutrients. Meat is the best source that will have amino acids. Thus, option D is correct.

What are amino acids and proteins?

Amino acids are the building blocks that make the macromolecule, a protein required for functioning, strength, and activities of the body. Amino acid-containing foods like eggs, meat, and soybeans are rich in proteins.

Amino acids and proteins are essential for body growth and repair that can be gained from poultry sources like eggs, meat, fish, cheese, quinoa, beans, etc. Bread, fruits, and butter are rich in carbohydrates.

Therefore, option D. meat is rich in amino acids.

Learn more about proteins here:

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Suppose Gabor, a scuba diver, is at a depth of 15m15m. Assume that: The air pressure in his air tract is the same as the net water pressure at this depth. This prevents water from coming in through his nose. The temperature of the air is constant (body temperature). The air acts as an ideal gas. Salt water has an average density of around 1.03 g/cm3g/cm3, which translates to an increase in pressure of 1.00 atmatm for every 10.0 mm of depth below the surface. Therefore, for example, at 10.0 mm, the net pressure is 2.00 atmatm. What is the ratio of the molar concentration of gases in Gabor's lungs at the depth of 15 meters to that at the surface

Answers

Answer:

The ration of molar concentration is "2.5".

Explanation:

The given values are:

Average density of salt water,

= [tex]1.03 \ g/cm^3[/tex]

Net pressure,

= [tex]2.00 \ atm[/tex]

Increase in pressure,

= [tex]1.00 \ atm[/tex]

Now,

The under water pressure will be:

=  [tex]\frac{15 \ m}{10}\times 1 \ atm +1 \ atm[/tex]

=  [tex]1.5\times 1+1[/tex]

=  [tex]1.5+1[/tex]

=  [tex]2.5 \ atm[/tex]

hence,

The ratio will be:

=  [tex]\frac{(\frac{n}{V})_{15m} }{(\frac{n}{V})_{surface} }[/tex]

or,

=  [tex]\frac{P}{P_s}[/tex]

=  [tex]\frac{2.5}{1}[/tex]

=  [tex]2.5[/tex]

how to write an article?​

Answers

Answer:

essay typer.com click the first link

→ Search the internet to understand the reaction between (Zno) & (HNO3).
a) Describe what happens to the first spoonful of powder when he mixes it with the acid.
b) Describe what would happen if the student kept adding zinc oxide to the nitric acid
after the reaction between the acid and metal oxide was complete.

Answers

Answer:

See Explanation

Explanation:

The equation of the reaction is;

ZnO(s) + 2HNO3(aq) --------> Zn(NO3)2(aq) + H2O(l)

a) When you first add ZnO to aqueous HNO3, the powder dissolves as it mixes with the acid.

b) If the student keeps on adding more ZnO powder to the HNO3 after the  reaction between the acid and metal oxide was complete, the powder will no longer dissolve in the acid. At this point, the reaction has attained equilibrium.

Ionic, metallic, or covalent??? Need now

Answers

Answer:

Covalent

Explanation:

What is a solution?
A. The substance that is dissolved in another substance
B. The mixture of one substance dissolved in another
C. The substance that dissolves another substance
D. Two liquids that do not mix with each other
SUR

Answers

Answer:

B

Explanation:

this is because solution is the mixture of a solvent and a solute to give you a solution

Answer:

B. The mixture of one substance dissolved in another

Explanation:

The blank
and
blank
of atoms are the same on both sides of
a chemical equation.

Please just answer the question directly instead of giving me some weird cryptic answer that I can’t use. I’ve seen this exact question answered before and nobody would give a straight answer.

Answers

I think it’s “number” and “type”
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