To make 1 L of citrate buffer (pH 3.0 to 6.2), follow these instructions
A. 800 mL of distilled water should be ready in a convenient container.
B. Add the solution with 25.703 g of sodium citrate dihydrate.
C. Add 2.421 g of citric acid in the mixture.
D. Use HCl or NaOH to adjust the solution's pH to the appropriate level.
E. Add distilled water until there is 1 L in the container.
What is a buffer?
Buffer solution refers to a solution whose pH is not significantly changed by the addition of modest amounts of either an acid or a basic. The solution of reserve acidity or alkalinity that resists pH change upon the addition of a modest amount of acid or alkali is known as a buffer.
Use these directions to create 1 L of citrate buffer (pH 3.0 to 6.2).
A handy container with 800 mL of distilled water should be prepared.
B. Include the sodium citrate dihydrate solution, which contains 25.703 g.
C. Include the mixture with 2.421 g of citric acid.
D. To bring the pH of the solution to the proper range, use HCl or NaOH.
E. Fill the container with distilled water until it measures 1 L.
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How much more average Kinetic Energy do molecules have at 50°C compared to 25°C?
The kinetic energy is 0.5177 × 10⁻²¹ J more at 50°C compared to 25°C.
The average kinetic energy of a molecule is directly proportional to the absolute temperature of a gas.
KE = ( 3/2 ) ( R / Nₐ ) T
Where T is the temperature of the molecule, R is the gas constant, and Nₐ is Avogadro's number.
Now, R = 8.314 J/mol.K
Avogadro's number, Nₐ = 6.022 × 10²³ atoms/ mol
The average kinetic energy at 50° C is:
T = 50° C = 323 K
KE₁ = ( 3/2 ) × ( R / Nₐ ) × T₁
KE₁ = ( 3 × 8.314 × 323 ) / ( 2 × 6.022 × 10²³ )
KE₁ = 668.90 × 10⁻²³ J
KE₁ = 6.6890 × 10⁻²¹ J
The average kinetic energy at 25°C is:
KE₂ = ( 3/2 ) × ( R / Nₐ ) × T₂
KE₂ = ( 3 × 8.314 × 298 ) / ( 2 × 6.022 × 10²³ )
KE₂ = 617.13 × 10⁻²³ J
KE₂ = 6.1713 × 10⁻²¹ J
Now,
The average kinetic energy of the molecules at 50° C compared to 25° C is:
KE = KE₁ - KE₂
KE = 6.6890 × 10⁻²¹ - 6.1713 × 10⁻²¹
KE = 0.5177 × 10⁻²¹ J
Hence, the average kinetic energy is 0.5177 × 10⁻²¹ J more at 50° C compared to 25° C.
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Calculate the ph of a buffer solution obtained by dissolving 17.0 g of kh2po4(s) and 30.0 g of na2hpo4(s) in water and then diluting to 1.00 l.ph=
The ph of a buffer solution was obtained by dissolving 17.0 g of [tex]KH_{2} PO_{4}[/tex] and 30.0 g of [tex]Na_{2} HPO_{4}[/tex] in water and then diluting to 1.00L is 7.43.
We will apply the Henderson-Hasselblach equation to determine the pH:
pH= pKa + Log [A/AH]
when [tex]Na_{2} HPO_{4}[/tex] molar mass is 142 g/mol
A is the conjugate base [tex]HPO_{4} ^{-}[/tex] ions and as a result,
[tex][A]= \frac{30g}{142 g/mol}[/tex]
= 0.211 M
[tex]KH_{2} PO_{4}[/tex] has a molar mass of 136 g/mol.
Given that AH is the weak acid [tex]H_{2} PO_{4} ^{-}[/tex] ion,
[AH] = [tex]\frac{17.0 g}{136 g/mol.}[/tex]
= 0.125 M
and with [tex]H_{3} PO_{4}[/tex] having a pKa value of 7.21
then, substituting
∴ pH = 7.21 + log (0.211 / 0.125)
= 7.21 +0.227
=7.43
The pH of a buffer solution is 7.43.
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The number of neutrons present in the nucleus of an average atom of any given element is best estimated by:_______-
The number of neutrons present in the nucleus of an average atom in any given element is best estimated by subtracting the number of protons from the mass number.
All atoms contain protons, neutrons and electrons, although the amount differs for each atom. Neutrons are located in the nucleus of each atom. They were first discovered by James Chadwick. They are also neutral and have no charge.
Apart from neutrons, positively charged protons are present in the nucleus. The number of protons is equal to the atomic number, usually denoted with the letter Z.
The mass number or atomic mass is the total mass of the atom. It is calculated by adding the number of protons to the number of neutrons. Electrons are really light and have negligible mass (about 1/1840 times the mass of a proton), so we don't add their masses when calculating mass number. So, to get the number of neutrons in an atom, subtract the number of protons from the mass number.
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Helpppppppppp!!! the law of conservation of mass states that during a chemical reaction, mass/matter is not __________________________ or ________________________. because of this law, there must be exactly the same number and kind of _____________________ on each side of a chemical equation. to check if an equation is balanced or not, simply count the number of atoms of each element on the reactant side of the equation and check to see if there are the same number of atoms of each element on the ______________________ side of the equation. if so, it is balanced.
Answer: created, destroyed, element, product
Explanation: The law of conservation of mass states that matter can neither be created nor destroyed but is transferred from one form to another. In other words, the mass of one element at the beginning of the reaction must be equal to the mass of the element at the end of the reaction.
So...the law of conservation of mass states that during a chemical reaction, mass/matter is not CREATED or DESTROYED and because of this law, there must be exactly the same number and kind of ELEMENTS on each side of a chemical equation.
To check if an equation is balanced or not, simply count the number of atoms of each element on the reactant side of the equation and check to see if there are the same number of atoms of each element on the PRODUCT side of the equation. If so, it is balanced.
The amount of energy that must be absorbed or lost to raise or lower the temperature of 1gram of liquid water by 1°c.
The amount of energy that must be absorbed or lost to raise or lower the temperature of 1 gram of liquid water by 1°C is 1 calorie.
A calorie (cal), or a small calorie, is the amount of energy needed to heat one gram of water by one degree Celsius. It is used to express the amount of energy released in a phase change or chemical reaction.
One small calorie is approximately 4.2 joules.
A calorie is a unit of energy.
A calorie was originally part of the metric system (SI), but now it is replaced with the joule (J).
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The boiling point of ethanol is 173.1°F. A lab group measures the boiling point as 185°F. What is the absolute error and the percent error?
Due to the hydrogen bonding between the molecules of ethanol and water, it is True.
Water and ethanol form weak hydrogen bonds with aromatic hydrogen atoms and strong hydrogen bonds with the hydroxyl, carbonyl, and ether groups in chrysin/galangin. Although less frequently than in water, ethanol molecules can form hydrogen bonds with one another. The fact that there is only one hydrogen with a significant Positive charge in each ethanol molecule limits the hydrogen bonding. Between adjoining hydrogen and oxygen atoms of nearby water molecules, hydrogen bonds are formed. A bond called a hydrogen bond is produced by the attraction between individual water molecules.
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Boron (B) is an element or a compound?
Answer:
Its a element
Explanation:
Boron is made of atoms.
Answer:
element is the answer for your question
Explanation:
because i took a test on this
What mass of hydrogen is needed to produce 5.0 g of tungsten according to the equation: WO3 + 3 H2 --> 3 H2O + W
The mass of hydrogen that is needed to produce 5.0 g of tungsten is 0.0273 grams.
What is tungsten?Tungsten is a chemical element that is used with steel to make the steel strong.
The equation:
WO₃ + 3H₂ --> 3H₂O + W
Given, that the mass is 5.0 g of tungsten
The molar mass of tungsten is 183.84 g/mol
Moles = mass / molar mass
5.0 / 183.84 = 0.0271 moles
Then, the Mass of hydrogen
The molar mass of hydrogen is 1.00784
Moles of tungsten are 0.0271 moles
molar mass x moles
1.00784 x 0.0271 moles
0.0273
Thus, the mass of hydrogen needed is 0.0273 grams.
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Does vb theory indicate that the diatomic molecule he2 is a viable species? rationalize your answer
VB theory does not indicate that the diatomic molecule He₂ is a viable species.
Helium has atomic number 2, it has 2 protons and 2 electrons.
Electron configuration of helium atom: ₂He 1s².
Helim (He) is a noble gas.
Noble gases (group 18) are in group 18: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn). They have very low chemical reactivity.
Noble gases have very stable electron configuration and does not need to gain electrons, only when they gain energy.
Valence bond (VB) theory explains chemical bonding.
Helium atom is stable and does not form molecule.
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What property of matter is measured in cubic centimeters?
Volume is the correct answer
What is the mass of 7.00 mol of hydrogen peroxide (h2o2)? 0.206 g 0.389 g 126 g 238 g
The mass of the hydrogen peroxide is 238 g.
Hydrogen peroxide at room temperature stays in liquid form. It has a bitter taste and is colorless. It is an important regent used in pharmaceutical and other industries. It also has medical use. It can be used as an antiseptic.
The number of miles in the hydrogen peroxide is n.
n = 7 mol
The molar mass of hydrogen peroxide is,
The molar mass of hydrogen peroxide = Molar mass of hydrogen + Molar mass of oxygen
= 2 × 1 + 2× 16
= 34 g/mole
The molar mass of hydrogen peroxide is 34 g/mole.
The mass of the hydrogen peroxide is,
[tex]Number \: of \: moles = \frac{ Mass }{ Molar \: mass}[/tex]
[tex]n = \frac{m}{M} [/tex]
m = n × M
m = 7 × 34
m = 238 g.
Therefore, the mass of the hydrogen peroxide is 238 g.
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How to understand significant digits I know that leading zeros aren’t significant, but can someone explain more about significant digits i’m trying to understand it
Which occurs during a synthesis reaction?
●
A. Compounds break down into simpler products.
B. Two or more substances combine to form a more complex substance.
C. One element replaces another element in a compound.
D. Two elements in different compounds trade places.
bro i need help asap
P2O5 was found to have a ph of 2.0 . Give reasons for this observation
It is because the traditional definition of a strong acid is based on the simplicity of proton (hydrogen ion) donation in aqueous solution.
Which acid is formed by P2O5?The chemical compound phosphorus pentoxide has the molecular formula P4O10 (with its common name derived from its empirical formula, P2O5). The anhydride of phosphoric acid is this white, crystalline solid. When P2O5 is dissolved in water, it produces H3PO4, or phosphoric acid (3H2O + P2O5 2H3PO4).
Why is it called P2O5 as diphosphorus pentoxide?Phosphorus pentoxide has a molecular formula of P4O10, but its empirical formula is P2O5. But the name of the compound, not its molecular formula, was derived from its empirical formula. The official name for all of this substance is diphosphorus pentoxide.
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A solution is prepared by dissolving 50.4 g sucrose (c12h22o11) in 0.332 kg of water. the final volume of the solution is 355 ml. for this solution, calculate the molarity.
The molarity of the sucrose solution is found to be 0.4146M
The term "molarity" (also known as "molar concentration," "amount concentration," or "substance concentration") refers to the amount of a substance per unit volume of the solution and is used to describe the concentration of a chemical substance, specifically a solute, in a solution.
Given:
Mass of sucrose, m = 50.4g
Volume of solution, v = 355ml = 0.355L
Molecular weight of sucrose = 342.3g/mol
To find:
Molarity, M = ?
Formula:
Molarity = amount of solute, n (moles) / volume of solution, v (L)
Calculations:
No. of moles of sucrose, n = mass of sucrose x (1 mole / molecular weight of sucrose)
n = 50.4 x (1/342.3)
n = 0.1472 moles
M = 0.1472 / 0.355
Molarity = 0.4146M
Result:
The sucrose solution has a molarity of 0.4146M.
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How many electrons would it take to equal the mass of a helium nucleus?
EXPRESS YOUR ANSWER USING TWO SIGNIFICANT FIGURES.
The electrons will take 7.3 times to be equal to the mass of the helium nucleus
How many electrons would it take to equal the mass of a helium nucleus?
If we want to calculate the number of electrons in the nucleus of the helium, then we have the formula for finding the number of electrons so by doing so we can get exactly the number of electrons.
The formula is that if we divide the total mass of the nucleus of the helium gas with the number of electronic mass so it will give us the number. So as a result it will take $7.28869 \times {10^{ - 59}}$ number of electrons to equal the mass of a helium nucleus.
The atomic mass of the Helium is 4.002602.
So we can conclude that the electrons will take 7.3 times to be equal to the mass of the helium nucleus.
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HELP.....................................................
Answer:
I believe that would be a liquid.
Explanation:
What effect did the copper wire have on the candle flame? Propose a hypothesis.
Answer:
The flame of the candle looks to go out, but the candle continues to burn. In actuality, the copper wire coil is transferring heat away from the candle flame. The flame returns after the coil of wire is removed.
Explanation:
What+are+the+molar+enthalpy+and+total+enthalpy+of+the+pure+system+when+50%+and+75%+have+been+evaporated?
At 30°C, Molar enthalpy will be 72,446.4 J/mole and total enthalpy will be 26.5 kJ.
At 50°C, Molar enthalpy will be 3,63,792J/mole and total enthalpy will be 132.5 kJ.
What is Molar enthalpy?The enthalpy value per mole is known as molecular enthalpy. Enthalpy is a thermodynamic quantity that, according to this definition, is equivalent to a system's entire heat capacity. It is equal to the sum of the system's internal energy and the volume times pressure product. KJ/mol serves as the unit of measurement for this value. As a result, we can arrive at the following equation to determine molar enthalpy:
DH/n = Molar Enthalpy n is the number of moles of reactant used in the system, and DH is the change in enthalpy of the system. For instance, the change in enthalpy when one mole of a chemical species is created in the standard state at a certain temperature is known as the molar enthalpy for the creation of a specific substance.
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What byproduct of fermentation induces the coagulation of casein into the cheese curd? select one:
a. carbon dioxide
b. lactic acid
c. ethyl alcohol
d. acetic acid
The byproduct of fermentation tha induces the coagulation of casein into the cheese curd is b. lactic acid.
Lactic acid causes the milk proteins casein to form into a cheese curd, because it increase acidity and the enzymes prefer for the coagulation.
Producing cheese curds is one of the first steps of makint a cheese.
Swiss cheese is a cheese made in Switzerland.
Swiss cheese is, usually, a semihard cheese made from cows milk with a characteristic holes.
Fermentation of milk is a metabolic process in which lactic acid (CH₃CHOHCOOH) and carbon dioxide are produced from sugar lactose:
C₅H₁₂O₆ → CH₃CHOHCOOH + C₂H₅OH + CO₂
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What is the purpose of adding water to a sample of vinegar used in the titration?
Water is added to vinegar, which already contains acetic acid, to dilute it while keeping the same number of moles in the acid solution.
This makes it easy to determine the titration's end point, which helps ensure appropriate titration and accurate results.
Since the number of acid moles in the solution does not vary with the addition of water, the additional volume caused by the addition of water is not taken into account in the calculations.
What is Titration?Titration is the process of adding one solution to another so that the reaction occurs under circumstances that allow the increased volume to be precisely measured. It is employed in quantitative analytical chemistry to ascertain an unidentified analyte's concentration. Titrations can entail different sorts of reactions as well as the acid-base reactions that are most frequently associated with them. Titration is often referred to as volumetric analysis or titrimetry. The term "analyte" or "titrand" refers to the chemical with an unknown concentration. The titrant or titrator is a standard solution of a reagent with a known concentration. The titration volume refers to the amount of titrant that reacts (often to generate a color change).To learn more about Titration, refer to:
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What will happen if i mix black coffee and white sugar together?
Explanation:
It drowns out some of the more delicate notes. It changes the flavour balance.
The specific heat capacities of lead and magnesium are (in j/g-degree): 0.128 and 1.024. Calculate the molar heat capacities of these metals.
Given,
Specific heat capacity of lead = 0.128 J/g
Specific heat capacity of magnesium= 1.024 J/g
Molar heat capacity is the amount of heat needed to raise the temperature of 1 mole of a substance by 1 unit.
So,
For calculating molar heat capacity we need to multiply the specific heat capacities of the metals with their atomic masses.
Atomic mass of lead (Pb) = 207
Atomic mass of magnesium (Mg) = 24
∴ Molar heat capacity = specific heat capacity x atomic mass
Molar heat capacity of Pb=0.128 x 207 = 26.5 J
Molar heat capacity of magnesium (Mg) = 1.024 x 24 = 24.5
Hence , molar heat capacities of lead and magnesium are 26.5 and 25.5 Joules respectively.
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Molar heat capacities of lead and magnesium is 26.49 and 24.5 Joules, respectively.
Given,
Lead has a specific heat capacity of 0.128 J/g.
Magnesium has a specific heat capacity of 1.024 J/g.
The quantity of heat required to increase the temperature of 1 mole of a substance by 1 unit is known as its molar heat capacity.
So, We must multiply the specific heat capacities of the metals by their atomic masses in order to determine their molar heat capacities.
Lead (Pb) has an atomic mass of 207.
Magnesium (Mg) has an atomic mass of 24.
Specific heat capacity multiplied by atomic mass gives the molar heat capacity.
Pb has a 26.5 J molar heat capacity (0.128 x 207).
Magnesium's (Mg) molar heat capacity is equal to 1.024 x 24.
Thus, lead and magnesium have molar heat capacities of 26.49 and 24.5 Joules, respectively.
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Is a non-carbonated soft drink a heterogeneous mixture, solution, compound, or element?
Answer:
A non-carbonated soft drink is a homogenous mixture or a solution
Explanation:
Non-carbonated soft drinks contains water, sweetener that are evenly mixed (or uniformly mixed if this is the reagents). And since we don't see and bubbles when it's in the drink the soft drink is a solution because the components are evenly mixed.
the small particles within the atom
are known as?
Answer:
molecules
Explanation:
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The densities of copper, silver, iron, and magnesium are 8.96,10.5,7.89,1.74g\slashcm3 in that order. you are given 5.00 grams of each metal. which one has the largest volume?
The element that has the largest volume is Magnesium
The density formula and the procedure we will use is:
d = m/v
Where:
v= volumed= densitym= massInformation about the problem:
d(copper)= 8.96 g/mld(silver)= 10.5 g/mld(iron)= 7.89 g/mld(magnesium )= 1.74 g/mlm = 5 gv = ?Applying the density formula and clearing the volume we get:
d = m/v
v = m/ d
v(copper) = m/d(copper)
v(copper) = 5 g/ 8.96 g/ml
v(copper) = 0.5580 ml
v(silver) = m/d(silver)
v(silver) = 5 g/ 10.5 g/ml
v(silver) = 0.4762 ml
v(iron) = m/d(iron)
v(iron) = 5 g/ 7.89 g/ml
v(iron) = 0.6337 ml
v(magnesium ) = m/d(magnesium )
v(magnesium ) = 5 g/ 1.74 g/ml
v(magnesium ) = 2.8736 ml
What is density?It is a physical quantity that expresses the ratio of the body mass to the volume it occupies.
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Sometimes when performing a crystallization, one solvent alone will not work and you have to use a solvent-pair. Will the solvent pair hexane and diethyl ether work? why or why not?.
Answer:
k
Explanation:
k7
A 35m x 15m swimming pool is filled with water to a depth of 3m. how much heat is required to raise the temperature of the water in the pool from 10c to 25c?
It avoids the need to make tedious, and uncertain, calculations to estimate the shell-side coefficient.
What is shell-side coefficient?In steady flow systems, tube-side heat transfer coefficients are capable of being greatly improved over flow at the same net flow Reynolds number. The Nusselt values converge, as shown in Figure 5.21, at higher Reynolds numbers, although operation at such high net flow Reynolds numbers would negate the benefits of adopting OBRs in the design. Nu is often increased by a factor of between 10 and 30 in the lower Re region.
Due to the improved radial transport exhibited by the vertical mixing patterns, this improvement has occurred. It is obvious that in an oscillating baffled system, heat transfer coefficients that are comparable to those of smooth-walled tubes under well-developed turbulence can be attained at significantly lower (net flow) Reynolds numbers.
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Which of following can form hydrogen bonds with water molecules?
(1) na
(2) ch 3cooh
(3) c 2h 6
(4) ch 3nh 2
Of the four species, only
CH₃COOH and CH₃NH₂ hydrogen bond
COOH can be formed via Water H and NH₂
Group. The species Na+ can be solvated with water through ionic dipole interactions rather than hydrogen bonding. As for C₂H₆ it can interact with water only by weak London dispersion forces
Hydrogen bonding refers to the attractive forces that occur between hydrogen atoms and highly electronegative atoms such as nitrogen, oxygen, and fluorine. These can occur intramolecularly or intermolecularly, depending on whether they occur in different molecules or in the same molecule. In general, hydrogen bonds are stronger than van der Waals forces, but weaker than ionic and covalent bonds.
Of the four species, only CH₃COOH and CH₃NH₂ hydrogen bond COOH can be formed via Water H and NH₂ Group. The species Na+ can be solvated with water through ionic dipole interactions rather than hydrogen bonding. As for
C₂H₆, it can interact with water only by weak London dispersion forces.
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