Answer:
Likely [tex]\rm In[/tex] (indium.)
Explanation:
Number of atoms: [tex]N = 2.241 \times 10^{21}[/tex].
Dividing, [tex]N[/tex], the number of atoms by the Avogadro constant, [tex]N_A \approx 6.023 \times 10^{23} \; \rm mol^{-1}[/tex], would give the number of moles of atoms in this sample:
[tex]\begin{aligned} n &= \frac{N}{N_{A}} \\ &\approx \frac{2.241 \times 10^{21}}{6.023 \times 10^{23}\; \rm mol^{-1}} \approx 3.72 \times 10^{-3}\; \rm mol \end{aligned}[/tex].
The mass of that many atom is [tex]m = 0.4272\; \rm g[/tex]. Estimate the average mass of one mole of atoms in this sample:
[tex]\begin{aligned}M &= \frac{m}{n} \\ &\approx \frac{0.4272\; \rm g}{3.72 \times 10^{-3}\; \rm mol} \approx 114.82\; \rm g \cdot mol^{-1}\end{aligned}[/tex].
The average mass of one mole of atoms of an element ([tex]114.82\; \rm g \cdot mol^{-1}[/tex] in this example) is numerically equal to the average atomic mass of that element. Refer to a modern periodic table and look for the element with average atomic mass [tex]114.82[/tex]. Indium, [tex]\rm In[/tex], is the closest match.
The symbol of the element is In
StoichiometryFrom the question, we are to determine the identity of the element
First, we will determine the number of moles of sample present
Using the formula
[tex]Number \ of\ moles = \frac{Number\ of \ atoms }{Avogadro's\ constant}[/tex]
Number of moles of the sample = [tex]\frac{2.241\times 10^{21} }{6.022\times 10^{23} }[/tex]
Number of moles of the sample = 0.003721355 mole
Now, we will determine the Atomic mass of the sample
From the formula,
[tex]Atomic\ mass = \frac{Mass}{Number\ of\ moles}[/tex]
Therefore,
Atomic mass of the sample = [tex]\frac{0.4272}{0.003721355}[/tex]
Atomic mass of the sample = 114.8 amu
The element that has an atomic mass of 114.8 amu is Indium. The symbol of Indium is In.
Hence, the symbol of the element is In.
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If a 520 mg sample of technetium-99 is used for diagnostic procedure, how much of Tc-99 remains after 30.0h? Half life of Tc-99 is 6.0 hours.
A 2.584 g sample of a compound containing only carbon, hydrogen, and oxygen is burned in an excess of dioxygen, producing 5.874 g CO2 and 2.404 g H2O. What mass of oxygen is contained in the original sample?a. 0.7119 g.b. 0.8463 g.c. 0.29168 g.d. 0.1793 g.e. 0.6230 g.
Answer:
a. 0.7119 g
Explanation:
To solve this question we need to know that all carbon of the compound will react producing CO2 and all Hydrogen producing H2O.
Thus, we can find the mass of C and the mass of H and by difference regard to the 2.584g of the compound we can find the mass of oxygen as follows:
Moles CO2 = Moles C -Molar mass: 44.01g/mol-
5.874g CO2 * (1mol/44.01g) = 0.1335 moles CO2 = 0.1335 moles C
Mass C -Molar mass: 12.01g/mol-:
0.1335 moles C * (12.01g /mol) = 1.6030g C
Moles H2O -Molar mass: 18.01g/mol-
2.404gH2O * (1mol / 18.01g) = 0.1335 moles H2O * (2mol H / 1mol H2O) = 0.267 moles H
Mass H -Molar mass: 1g/mol-
0.267 moles H * (1g/mol) = 0.2670g H
Mass Oxygen =
Mass O = 2.584g compound - 1.6030g C - 0.2670g H
Mass O = 0.714g O ≈
a. 0.7119 g
0.28 M Ca(NO3)2
Express your answer using two significant figures.
Answer:
Mass=Moles × RFM
Mass= 0.28M× 164
Mass= 45.92 grammes
Please help
In which atom do the valence electrons experience the larger electron affinity, Rb or
Sr? Explain why
Answer:
Explanation:
The electron affinity (EA) of an element is the energy change that occurs ... Atoms with the largest radii, which have the lowest ionization energies (affinity for their own valence electrons), also have the ... Based on their positions in the periodic table, which of Rb, Sr, or Xe would you
what would happen if the number of protons and electrons in the Atom did change
The following list of properties is most descriptive of a(n) ______________. Low melting point, non-conductor of electric current. Group of answer choices
Answer:
This question is incomplete
Explanation:
This question is incomplete but the completed question is below;
"The following list of properties is most descriptive of a(n) ______
1. High melting point, conductor of electricity when dissolved in water
2. Low melting point, non-conductor of electric current
3. Malleable, ductile, insoluble in water.
The choices for all 3 are: a) metallic solid b) molecular solid c) ionic solid d) all of these e) none of these f) more than one of these"
1. Ionic solid: Ionic solids are solids that have ionic/electrovalent bonds holding it's constituent molecules together. These bonds are strong bonds that involve the transfer of electrons from one constituent atom (the metal) to another constituent atom (the nonmetal). This strong bond causes the solid to have a high melting and boiling point. Also, when dissolved in water, the constituent atoms (involved in the electron transfer) dissociate to form ions (become charged) and thus easily carry electric charges (i.e conduct electricity).
Examples are Sodium Chloride and Potassium Iodide
2. Molecular solids: These are solids whose constituent molecules are held together by a weak bond/force known as Van der Waal forces. This forces are easily broken down when subjected to heat and thus the molecular solids have a low melting point. Also, these solids do not have carriers of heat or electric charges in them and are thus non-conductors of electric current.
Examples are Ice (frozen water) and sucrose
3. Metallic solids: These of solids made from constituent metal atoms only. The nuclei of these constituent metal atoms have the ability to move past one another without disrupting there metallic bonding; it is for this reason they are malleable and ductile. There constituent atoms however do not dissociate in water and are thus insoluble in water.
Examples are aluminium and copper crystal.
The absolute temperature of a gas is increased four times while maintaining a constant volume. What happens to the
pressure of the gas?
Olt decreases by a factor of four.
O It increases by a factor of four.
It decreases by a factor of eight
It increases by a factor of eight.
Answer:
The pressure increases by a factor of four.
Explanation:
Let's consider a gas at a given temperature and pressure (T₁, P₁). The absolute temperature of a gas is increased four times (T₂ = 4 T₁) while maintaining a constant volume. We can assess the effect on the pressure (P₂) by using Gay Lussac's law.
P₁/T₁ = P₂/T₂
P₂ = P₁ × T₂/T₁
P₂ = P₁ × 4 T₁/T₁
P₂ = 4 P₁
The pressure increases by a factor of four.
To what volume should you dilute 55 mL of 12 M stock HNO3 solution to obtain a 0.145 HNO3 solution?
Answer:
4552 mL
Explanation:
From the question given above, the following data were obtained:
Volume of stock solution (V₁) = 55 mL
Molarity of stock solution (M₁) = 12 M
Molarity of diluted solution (M₂) = 0.145 M
Volume of diluted solution (V₂) =?
The volume of the diluted solution can be obtained by using the dilution formula as illustrated below:
M₁V₁ = M₂V₂
12 × 55 = 0.145 × V₂
660 = 0.145 × V₂
Divide both side by 0.145
V₂ = 660 / 0.145
V₂ ≈ 4552 mL
Thus, the volume of the diluted solution is 4552 mL
Which technique is best suited to each application?
a. In the second week of a four week biochemistry experiement, you have 50 fractions collected from a gel filtration column to determine which fractions contain lactate dehydrogenase. You are given only 400 uL of 0.100 mg/mL lactate dehydrogenase to prepare your calibration curve. 96-well microplate
b. Your environmental lab has 2000 samples to be analyzed for trace ammonia by next week. discrete analyzer.
c. Twenty water samples must be analyzed for Cl-, NH3, PO3-, and So during each work shift. flow injection analysis colorimeter.
d. Your professor heard you will be hiking the Appalachian Trail next summer. She asks you to collect 100-mL water samples from the ten streams with the highest concentration of phosphate.
Answer:
a. discrete analyzer
b. 96 well microplate
c. flow injection analysis
d. colorimeter
Explanation:
96 well microplates are instruments designed for sample collection and throughput screening. If an environment lab has collected 2000 samples then 96 well microplate is best suited application. Discrete analyzer is automated chemical analyzer which performs test on samples kept in discrete cells. Flow injection analysis is approach used for chemical analysis. It injects a plug of sample into a flowing carrier stream. Colorimeter is a device which measures absorbance of wavelength of light by a specific solution.
from kinatic point of view explain the change from solid to liquied based on the effect of change of tempreture.
Answer:
Temperature affects the kinetic energy in a gas the most, followed by a comparable liquid, and then a comparable solid. The higher the temperature, the higher the average kinetic energy, but the magnitude of this difference depends on the amount of motion intrinsically present within these phases.
Explanation:
Liquids have more kinetic energy than solids. When a substance increases in temperature, heat is being added, and its particles are gaining kinetic energy. Because of their close proximity to one another, liquid and solid particles experience intermolecular forces. These forces keep particles close together.
What kind of element is Phosphorus is
Answer:
NON-METAL
Explanation:
Phosphorus is a non-metal that sits just below nitrogen in group 15 of the periodic table. This element exists in several forms, of which white and red are the best known.
The elemental mass percent composition of succinic acid is 40.68% C, 5.12% H, and 54.19% O. Determine the empirical formula of succinic acid. Express your answer as a chemical formula.
Answer:
C₂H₃O₂
Explanation:
To determine the empirical formula of succinic acid, we need to follow a series of steps.
Step 1: Divide each mass percent by the atomic mass of the element
C: 40.68/12.01 = 3.39
H: 5.12/1.01 = 5.07
O: 54.19/16.00 = 3.39
Step 2: Divide all the numbers by the smallest one, i.e. 3.39
C: 3.39/3.39 = 1
H: 5.07/3.39 ≈ 1.5
O: 3.39/3.39 = 1
Step 3: Multiply all the numbers by a factor that makes them all integers, i.e. 2
C: 1 × 2 = 2
H: 1.5 × 2 = 3
O: 1 × 2 = 2
The empirical formula of succinic acid is C₂H₃O₂.
What is the molarity of a solution prepared by dissolving 12.0 g of potassium permanganate, KMnO4, in water to make 250.0 mL of solution
Answer:
Explanation:
Molecular weight of potassium permanganate is 158 g .
12 g = 12 g / 158 g moles
= .076 moles .
250 mL = .25 L .
Molarity of solution = moles dissolved / volume of solution
= .076 / .25 L
= .304 M .
Molarity of solution is .304 M.
The molarity of a solution prepared by dissolving 12.0 g of potassium permanganate, KMnO4, in water to make 250.0 mL of solution will be 0.304 M. It can be calculated by using mole formula.
What is molarity ?The amount of material in a given volume of the given solution has been measured in molarity (M). The moles of a particular solute per liter of a solution can be known as molarity. The molar solution of known concentration is indeed known as molarity.
What is mole?A mole is just the quantity of a material that includes exactly 6.022 × [tex]10^{23}[/tex] of the particular chemical elementary entities.
Molecular weight potassium potassium permanganate = 12 g
Volume of the solution = 250mL = 25 L.
Calculation of mole:
Mole can be calculated by using the formula.
Mole = mass / molar mass
Mole = 12 g / 158 g
Mole = 0.076 mole.
Calculation of molarity:
Molarity can be calculated by using the molarity formula:
Molarity = moles of dissolved / volume of solution
Molarity = 0.076 / 0.25
Molarity = 0.304 M
Therefore, the molarity of the solution will be 0.304 M.
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2) If a brick has a length of 13.77 cm, a width of 8.50 cm, and a height of 5.12 cm:
a) What is the volume of the brick?
b) If the brick has a mass of 895.3 g, what is its density?
Answer:
a. 599 cm³
b. 1.49 g/cm³
Explanation:
A. VolumeVolume is the amount of space an object occupies. Since this is a brick, the object is a rectangular prism. The formula for the volume of a rectangular prism is the product of length, width, and height.
[tex]V= l *w*h[/tex]
The brick's length (l) is 13.77 centimeters, the width (w) is 8.50 centimeters, and the height (h) is 5.12 centimeters. Substitute these values into the formula.
[tex]V= 13.77 \ cm * 8.50 \ cm * 5.12 \ cm[/tex]
Multiply the numbers together.
[tex]V= 117.045 \ cm^ 2* 5.12 \ cm[/tex]
[tex]V= 599.2704 \ cm^3[/tex]
The original measurements have at least 3 significant figures, so our answer must have 3. For the number we calculated, that is the ones place. The 2 in the tenths place tells us to leave the 9 in the ones place.
[tex]V \approx 599 \ cm^3[/tex]
[tex]\bold {The \ volume \ of \ the \ brick \ is \ approximately \ 599 \ cubic \ centimeters}}[/tex]
2. DensityDensity is the amount of matter in a specified space. The formula for density is mass over volume.
[tex]d= \frac{m}{v}[/tex]
The mass of the brick is 895.3 grams and we just found the volume to be 599.2704 cubic centimeters. Substitute the values into the formula.
[tex]d= \frac{895.3 \ g}{599 \ cm^3}[/tex]
Divide.
[tex]d= 1.494657763 \ g/cm^3[/tex]
Round to three significant figures. For the number we calculated, that is the hundredth place. The 4 in the thousandth place tells us to leave the 9 in the hundredth place.
[tex]d \approx 1.49 \ g/cm^3[/tex]
[tex]\bold {The \ density\ of \ the \ brick \ is \ approximately \ 1.49 \ grams /cubic \ centimeters}}[/tex]
net ionic equation for 2AgF(aq) + k2S = Ag2S (s) + 2KF(aq)
Answer:
The net ionic equation shows the actual reaction more clearly and closer to reality because it writes soluble ionic compounds as the ions and then cancel the spectator ions not involved in the chemical reaction . The net ionic equation results shows the actual chemical reaction taking place.
The net ionic equation for for 2AgF(aq) + k₂S = Ag₂S (s) + 2KF(aq) will be; 2 Ag⁺(aq) + S²⁻(aq) → Ag₂S(s).
To write the net ionic equation for the reaction, we first need to write the balanced molecular equation and then convert it into the ionic equation before finally identifying the net ionic equation.
Write the balanced molecular equation:
2 AgF(aq) + K₂S(aq) → Ag₂S(s) + 2 KF(aq)
In this reaction, silver fluoride (AgF) reacts with potassium sulfide (K₂S) to produce silver sulfide (Ag₂S) and potassium fluoride (KF).
Write the complete ionic equation:
In the complete ionic equation, we separate all the aqueous species (dissociated ions) into their individual ions. Only the solid (s) and gas (g) compounds remain unchanged.
2 Ag⁺(aq) + 2 F⁻(aq) + 2 K⁺(aq) + S²⁻(aq) → Ag₂S(s) + 2 K⁺(aq) + 2 F⁻(aq)
Identify the spectator ions and then write the net ionic equation:
The spectator ions are the ions that do not participate in the actual chemical reaction and remain the same on both sides of the equation. In this reaction, the potassium ions (K⁺) and fluoride ions (F⁻) are spectator ions because they appear on both sides of the equation unchanged.
Net ionic equation:
2 Ag⁺(aq) + S²⁻(aq) → Ag₂S(s)
The net ionic equation shows only the species that actively participate in the chemical reaction. In this case, the silver ions (Ag⁺) and sulfide ions (S²⁻) are the ones involved in forming the silver sulfide (Ag₂S) precipitate.
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--The given question is incomplete, the complete question is
"Write the net ionic equation for this reaction. 2AgF(aq) + k₂S = Ag₂S (s) + 2KF(aq)."--
What is the molecular geometry of CIO3F as predicted by the VSEPR model?
Multiple Choice
trigonal pyramidal
square planar
square pyramidal
tetrahedral
octahedral
Explanation:
since there are no lone pairs on the central atom, the shape will be tetrahedral
Carbon monoxide, a product of combustion, is a toxic gas that has an extremely high affinity for hemoglobin (much higher than that of oxygen for hemoglobin); consequently, as soon as it dissolves in the liquid part of blood at low partial pressure, it diffuses quickly into red blood cells and binds to hemoglobin. In carbon monoxide (CO) poisoning, even with very low partial pressure of inspired CO, CO rapidly binds to hemoglobin (Hgb), leaving a lower fraction of oxygen binding sites on Hgb available to be occupied by oxygen. What would you expect to find if you measure the arterial PO2 of a person with CO poisoning
Answer:
Decreases.
Explanation:
The arterial PO2 of a person is decreasing because of carbonmonoxide poisoning due to higher affinity to hemoglobin than oxygen. The PO2 in the blood of arteries are used up by the cells and then there is higher concentration of carbonmonoxide in the blood as compared to oxygen. Due to this higher amount of carbonmonoxide in the blood, many complications occur such as headache, dizziness, weakness, upset stomach, vomiting, chest pain, and confusion.
Plastic is a polymer
-True
-False
TRUE
Explanation:
*not sure about this answer
which molecule has 9 carbon atoms
Answer:
c9h8o2
Explanation:
The molecule which has 9 carbon atom is [tex]C_{9} H_{8} O[/tex](cinnamaldehyde).
What is molecule?More than one atoms make up a molecule. If they have more than one atom, atoms could be the same for example, an oxygen molecule contains two oxygen atoms) as well as different (for example, a hydrogen molecule contains two hydrogen atoms.
What is cinnamaldehyde?Cinnamaldehyde is a kind of organic chemical with the formula C6H5CH=CHCHO and the formula C6H5CH=CHCHO. It's mostly the trans isomer that's found in nature.
It is known that the number of carbon atom is 9 hence molecule will be cinnamaldehyde
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What type of intermolecular force exist between H2O and Br2
Answer:
welcome to mobile legends
Explanation:
ml ka muna maya kana mag module
The tabulated data show the rate constant of a reaction measured at several different temperatures. Use an Arrhenius plot to determine the activation barrier and frequency factor for the reaction.
Temperature (K) Rate Constant (1/s)
300 0.0134
310 0.0407
320 0.114
330 0.303
340 0.757
Required:
Use an Arrhenius plot to determine the activation barrier for the reaction.
Answer:
e−(Ea/RT): the fraction of the molecules present in a gas which have energies equal to or in excess of activation energy at a particular temperature
Calculate the boiling point of a 3.5 % solution (by weight) of sodium chloride in water.
Kb of H2O = 0.512 oC/M
Answer: The boiling point of the solution is [tex]101.02^oC[/tex]
Explanation:
We are given:
3.5 % (by weight) NaCl
This means that 3.5 g of NaCl is present in 100 g of solution
Mass of solvent = Mass of solution - Mass of solute
Mass of solvent (water) = (100 - 3.5) g = 96.5 g
Elevation in the boiling point is defined as the difference between the boiling point of the solution and the boiling point of the pure solvent.
The expression for the calculation of elevation in boiling point is:
[tex]\text{Boiling point of solution}-\text{boiling point of pure solvent}=i\times K_b\times m[/tex]
OR
[tex]\text{Boiling point of solution}-\text{Boiling point of pure solvent}=i\times K_f\times \frac{m_{solute}\times 1000}{M_{solute}\times w_{solvent}\text{(in g)}}[/tex] ......(1)
where,
Boiling point of pure solvent (water) = [tex]100^oC[/tex]
Boiling point of solution = ?
i = Vant Hoff factor = 2 (for NaCl)
[tex]K_b[/tex] = Boiling point elevation constant = [tex]0.512^oC/m[/tex]
[tex]m_{solute}[/tex] = Given mass of solute (NaCl) = 3.5 g
[tex]M_{solute}[/tex] = Molar mass of solute (NaCl) = 36.5 g/mol
[tex]w_{solvent}[/tex] = Mass of solvent (water) = 96.5 g
Putting values in equation 1, we get:
[tex]\text{Boiling point of solution}-(100)=2\times 0.512\times \frac{3.5\times 1000}{36.5\times 96.5}\\\\\text{Boiling point of solution}=(1.02+100)^oC\\\\\text{Boiling point of solution}=101.02^oC[/tex]
Hence, the boiling point of the solution is [tex]101.02^oC[/tex]
Match each type of muscle tissues to the action it performs in the body
Answer:
where are the muscle tissues
Carbonic anhydrase is strongly inhibited by the drug acetazolamide, which is used as a diuretic (i.e., to increase the production of urine) and to lower excessively high pressure in the eye (due to accumulation of intraocular fluid) in glaucoma.
a. True
b. False
Answer:
a. True
Explanation:
There is strong inhibition of Carbon Anhydrase by Aceta-zolamide Carbonic Anhydrase. The drug acetazolamide is used as diuretic which increase the urine production in human body. It lowers pressure in eye in glaucoma.
Write a balanced half-reaction for the reduction of liquid water to gaseous hydrogen in basic aqueous solution. Be sure to add physical state symbols where appropriate.
Answer:
2 H₂O(l) + 2 e⁻ ⇒ H₂(g) + 2 OH⁻(aq)
Explanation:
Let's consider the unbalanced half-reaction for the reduction of liquid water to gaseous hydrogen in basic aqueous solution.
H₂O(l) ⇒ H₂(g)
First, we will perform the mass balance. We will balance oxygen atoms by multiplying H₂O by 2 and adding 2 OH⁻ to the right side.
2 H₂O(l) ⇒ H₂(g) + 2 OH⁻(aq)
Then, we perform the charge balance by adding 2 electrons to the left side.
2 H₂O(l) + 2 e⁻ ⇒ H₂(g) + 2 OH⁻(aq)
How many atoms are in protons
Answer:
the number of protons in a atom is unique to each element
Explanation:
protons are about 99.86% as massive neutrons. The number of protons in a atom is unique to each element .For example carbon atoms have six protons in an atom is referred to as the atomic number of that element
A gas occupies a volume of 202 ml at a pressure of 505 torr. To what pressure must the gas be subject in order to change the volume to 65.0 ml
Answer:
1569 torr
Explanation:
Assuming ideal behaviour and constant temperature, we can solve this problem by using Boyle's law, which states:
V₁P₁ = V₂P₂Where in this case:
V₁ = 202 mLP₁ = 505 torrV₂ = 65.0 mLP₂ = ?We input the data given by the problem:
202 mL * 505 torr = 65.0 mL * P₂And solve for P₂:
P₂ = 1569 torrEthylene glycol (C2H6O2) is mixed with water to make auto engine coolants. How many grams of C2H6O2 are in 5.00 L of a 6.00 M aqueous solution
Answer:
1860g.
Explanation:
It is known that the molar mass of C2H6O2 is 62.08 g/mol.,
Now to solve for the number of moles of solute, one must multiply both
sides by the volume:
moles of solute = (6.00 M)(5.00 L) = 30.0 mol
Notice since the definition of molarity is mol/L, the
product M × L gives mol, a unit of amount.
Use the molar mass of C3H8O3, one can convert mol to g:
Mass m =30 mol × 62.08 g/mol
m = 1860g.
Hence, there are 1,860 g of C2H6O2 in the specified amount of
engine coolant.
3. At 35 C, a sample of gas has a volume of 256 ml and a pressure of 720.torr. What would the volume
be if the temperature were changed to 22 C and the pressure to 1.25 atmospheres
Answer:
The volume will be 185.83 mL.
Explanation:
Gay-Lussac's law indicates that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. Gay-Lussac's law can be expressed mathematically as follows:
[tex]\frac{P}{T} =k[/tex]
Where P = pressure, T = temperature, k = Constant
Boyle's law says that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. Boyle's law is expressed mathematically as:
P*V=k
Where P = pressure, V = volume, k = Constant
Finally, Charles's Law consists of the relationship that exists between the volume and the temperature of a certain quantity of ideal gas, which is kept at a constant pressure. For a given sum of gas at a constant pressure, as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases because the temperature is directly related to the energy of the movement of the gas molecules. .
In summary, Charles's law is a law that says that when the amount of gas and pressure are kept constant, the quotient that exists between the volume and the temperature will always have the same value:
[tex]\frac{V}{T} =k[/tex]
Combined law equation is the combination of three gas laws called Boyle's, Charlie's and Gay-Lusac's law:
[tex]\frac{P*V}{T} =k[/tex]
Studying two different states, an initial state 1 and a final state 2, it is satisfied:
[tex]\frac{P1*V1}{T1} =\frac{P2*V2}{T2}[/tex]
In this case:
P1= 720 torr V1= 256 mLT1= 35 C= 308 K (being 0 C= 273 K)P2= 1.25 atm= 950 torr (being 1 atm= 760 torr)V2= ?T2= 22 C= 295 KReplacing:
[tex]\frac{720 torr*256 mL}{308 K} =\frac{950 torr*V2}{295 K}[/tex]
Solving:
[tex]V2= \frac{295K}{950 torr} *\frac{720 torr*256 mL}{308 K}[/tex]
V2= 185.83 mL
The volume will be 185.83 mL.
Which acid or base (along with its corresponding salt) should be used to generate a buffer solution with pH around 3.5
Answer:
Formic acid
Sodium formiate
Explanation:
To determine acid or base that can generate a buffer solution with pH around 3.5, we have to think in the acid whose pKa = pH.
Although we have to also think in buffer capacity, a measure which can cause a change of 1 pH unit in 1 L of solution.
Buffer capacity does not only depend on the concentration of its components but also of the relationship between that concentrations.
When pH = pKa, buffer capacity is maximum which means that the concentration of conjugated species is the same and the ability to oppose pH changes is maximum.
One example with pH = pKa or nearly if:
COOH⁻ + Na⁺ → NaCOOH
HCOOH + H₂O → COOH⁻ + H₃O⁺ Ka: 1.8×10⁻⁴
pKa = 3.74
