The mass of the sodium salt of A- that we need to add to the buffer is [tex]M \times (0.050 x 10^{(7.35-pKa))[/tex] x V. The number of moles of the sodium salt of A- that we need is simply [tex](0.050 \times 10^{(7.35-pKa))[/tex] x V.
What is conjugate acid?
A conjugate acid is the species that is formed when a base gains a proton (H⁺). For example, in the reaction [tex]NH_3 + H_2O \rightleftharpoons NH^{4+} + OH^-[/tex], ammonia (NH₃) is a base that accepts a proton from water (H₂O) to form its conjugate acid, ammonium (NH⁴⁺).
To create a buffer with pH = 7.35, we need an acid whose pKa is close to this pH. From Example 18.5, we know that the pKa values for the three acids are:
Acetic acid ([tex]CH_3COOH[/tex]): pKa = 4.76
Hydrofluoric acid (HF): pKa = 3.15
Phosphoric acid ([tex]H_3PO_4[/tex]): pKa1 = 2.15, pKa2 = 7.20, pKa3 = 12.35
Of these, phosphoric acid has a pKa closest to the desired pH of 7.35, so we will choose it to create the buffer.
pH = pKa + log([A-]/[HA])
[A-] = [tex][HA](10^{(pH - pKa))[/tex]
[A-] = [tex]0.10 M(10^{(7.35 - 7.20))[/tex] = 0.126 M
So we need a 0.10 M solution of phosphoric acid and a 0.126 M solution of [tex]NaH_2PO_4[/tex] to create the buffer.
To find the mass of [tex]NaH_2PO_4[/tex] needed to make the 0.126 M solution, we can use the formula:
moles = concentration × volume
The volume of the 0.126 M solution we need is:
volume = 500.0 mL = 0.5000 L
So the number of moles of [tex]NaH_2PO_4[/tex] we need is:
moles = 0.126 M × 0.5000 L = 0.0630 moles
The molar mass of [tex]NaH_2PO_4[/tex] is:
(1 × 22.99) + (1 × 1.01) + (2 × 30.97) + (4 × 16.00) = 119.98 g/mol
So the mass of [tex]NaH_2PO_4[/tex] we need is:
mass = moles × molar mass = 0.0630 moles × 119.98 g/mol = 7.56 g
Therefore, we need 7.56 g of [tex]NaH_2PO_4[/tex] to make the buffer.
To find the number of moles of [tex]NaH_2PO_4[/tex] needed, we can use the formula:
moles = concentration × volume
The volume of the 0.126 M solution we need is:
volume = 500.0 mL = 0.5000 L
So the number of moles of [tex]NaH_2PO_4[/tex] we need is:
moles = 0.126 M × 0.5000 L = 0.0630 moles
Therefore, we need 0.0630 moles of [tex]NaH_2PO_4[/tex] to make the buffer.
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In general, what causes a sea breeze?
O
A. The difference in density between land and water
B. The difference in cloud cover between land and water
Ο Ο Ο
C. The difference in specific heat capacity between land and water
D. The difference in elevation between land and water
Answer:
The usual cause of sea breeze is the difference in specific heat capacity between land and water Land heats and cools more quickly than water. What is the cause of a sea breeze? The air over the land is warmed and rises, to a greater temperature than that over the sea.
Explanation:
Your answer is C ! <3
The difference in specific heat capacity between land and water is the cause of sea breeze.
What is sea breeze?land and ocean heat up at different rates, sea breezes often occur during hot, summer days. The land surface warms up more quickly than the water surface during the day. As a result, the air above land is warmer than that over water.
Just to refresh your memory, warmer air is lighter than cooler air. Warm air rises as a result. As a result, the warmer air above the ground is rising. The cooler air above the water is moving across the surface of the land to replace the rising heated air as it rises over the land.
This is the sea breeze, which is seen at the top of the next picture. The land breeze that happens is seen at the bottom of the following picture.
Therefore, The difference in specific heat capacity between land and water is the cause of sea breeze.
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Determine if you can swim in 1×10^27 molecules of water
Mars have more gravity than earth?
True or false?
Answer:
false
Explanation:
earth is larger than mars so it has more gravity
Answer: false
Explanation:
Which is the correct number of moles of NO that is produced from 13.2 moles of oxygen
gas, O2?
4NH3 + 502 —> 4N0 + 6H2O
10.6 mol NO
General Formulas and Concepts:Math
Pre-Algebra
Order of Operations: BPEMDAS
Brackets Parenthesis Exponents Multiplication Division Addition Subtraction Left to RightChemistry
Stoichiometry
Using Dimensional AnalysisExplanation:Step 1: Define
[RxN - Balanced] 4NH₃ + 5O₂ → 4NO + 6H₂O
[Given] 13.2 mol O₂
Step 2: Identify Conversions
[RxN] 5 mol O₂ → 4 mol NO
Step 3: Stoich
[DA] Set up: [tex]\displaystyle 13.2 \ mol \ O_2(\frac{4 \ mol \ NO}{5 \ mol \ O_2})[/tex][DA] Multiply/Divide [Cancel out units]: [tex]\displaystyle 10.56 \ mol \ NO[/tex]Step 4: Check
Follow sig fig rules and round. We are given 3 sig figs.
10.56 mol NO ≈ 10.6 mol NO
1) Write the symbol and charge for each individual ion
2) Balance the charge so that they equal to zero
3)Write the formula based on how many of each ion you used in step 2
6) Nitrogen and Barium
7) strontium and fluorine
8) iodine and calcium
9) magnesium and sulfur
10) Sulfur and aluminum
N -3
Ba +2
Sr +2
F -1
I -1
Ca +2
Mg +2
S -2
S -2
Al +3
//
Ba3N2
SrF2
CaI2
MgS
Al2S3
//
I don't really understand 2.
You are given 0.39 mol of niobium (Nb). How many grams of niobium do you have?
Answer:
36gNb
Explanation:
0.39 mol Nb*92.91g Nb/1 mol Nb=36 g Nb
20 mL of NaOH solution was added to the conical flask. Indicator was added & titrated with 0.1 M HCl solution. The HCl used in the titration was read as 18.3 mL. What is the molar concentration of NaOH?
Answer:
[NaOH] = 0.1 Molar ... Note => the brackets around formula;i.e., "[ ]" is generally accepted in the chemistry community as concentration in Molar terms.
Explanation:
The metathesis rxn, or double replacement rxn, equation is:
(Molarity x Volume) of acid = (Molarity x Volume) of base, or
(M·V)acid = (M·V)base => M(base) = M·V(acid)/V(base)
= 0.1M × 18.3ml / 20ml = 0.0915M(base) = 0.1M (1 sig-fig) = [NaOH]
what is the correct answer ?
Answer:
Element with 6s subshell
Explanation:
Reactivity of an element depends on the electronic configuration and position of element in the periodic table as reactivity increases as we go down the periodic table.
This is so because number of shell increases as move down the periodic table and the last electron is further away from the nucleus.
Element with 6s subshell is the largest among 3s and 4s subshell and has more number of shells so it will react more than 3s and 4s subshell.
Hence, the correct answer is "Element with 6s subshell".
What is (1.20 x 104 m) x (3.070 x 102m)
HELP!!!!!!!!
One use of CaCl 2 to salt roads in the winter. The equation that describes the change in freezing point of a solvent due to a solute is T f =i x K f x molality. How much would the freezing point decrease if a 3.23 molal (m) solution were achieved? (K f =1.86^ C/(mol/kg) for water and i = 3 for CaCl 2 )
Answer:
On contact with ice, calcium chloride forms brine rapidly, which lowers the freezing point of water and melts snow and ice quickly. Calcium chloride forms brine faster than other ice melters because its hygroscopic properties actually cause it to attract moisture from its surroundings
Explanation:
HOPE IT WILL HELP YOU
What is true of experimental designs that are used in scientific research? The designs use the same steps in every kind of research. The designs follow a general method that is familiar to all scientists. The designs ensure that the experimental data supports the hypothesis. The designs are kept secret so that others must do their own experiments.. The answer is B.) "The designs follow a general method that is familiar to all scientists."
Answer:
The designs ensure that the experimental.
Explanation:
Scientific research refers to the-fact finding inquiry to answer the questions related to natural processes. A hypothesis is a situation or an assumption that needs to be proved by applying scientific produces. Experimental design refers to the methodology, which is applied to conduct research.
The designs ensure that the experimental data support the hypothesis is the true statement regarding experimental designs that are used in scientific research because an experimental design should be concerned with the fact that it is relevant or appropriate to prove a hypothesis.
Answer:
its c. the designs follow a general method that is familiar to all scientists
Explanation:
The specific heat of gold is 0.126 J/gºC. How much energy is released
when a 350 g sample of gold is cooled from 88.5°C to 24.6°C?
Explanation:
Specific heat capacity of gold (S)
= 0.126 J /kg°C
mass (m) = 350 g = 0.35 kg
difference in temperature (dt)
= 88.5°C - 24.6°C
= 63.9° C
Now
Energy released (Q)
= m*s*dt
= 0.35 * 0.126 * 63.9
= 2.81799 Joule
Hope it will help :)
The Law of Superposition states
The number of......... in an atom is the difference between the mass number and the atomic number
A-Electrons
B-Neutrons
C-Protons
Answer: While the mass number is the sum of the protons and neutrons in an atom, the atomic number is only the number of protons. The atomic number is the value found associated with an element on the periodic table because it is the key to the element's identity.
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An Advil® cold and sinus capsule has a volume of 210. Mm3. How many microliters (µL) of the drug are needed to fill the capsule? ( 1 L = 106 µL)
Answer:
210 microliters of drug are needed to fill the capsule
Explanation:
As given in the question
1 liter is equal to [tex]10^6[/tex] micro liters
Volume of Capsule [tex]= 210[/tex] cubic millimeter
1 cubic millimeter [tex]= 10^{-3}[/tex] cubic meter
1 cubic meter [tex]= 10^3[/tex] liters
1 micro liter [tex]= 10^{-6}[/tex] micro liters
Converting [tex]210[/tex] cubic millimeter to micro liter
[tex]= 210 * (10^{-3})^3 * 10^3 \\= 210 * 10^{-6}\\= 210[/tex]micro liters
please help me!! (brainliest)
Answer:
ok
Explanation:
How many grams of H,O are needed to produce 13 g of NaOH? 2 Na,O2 + 2 H20-4 NaOH + O2
Answer:
This is a typical stoichiometry question.To answer this question you want to get a relationship between
N
a
2
O and NaOH.
So you can get a relationship between the moles of
N
a
2
O
and moles of NaOH by the concept of stoichiometry.
N
a
2
O +
H
2
O ----------------> 2 NaOH.
According to above balanced equation we can have the stoichiometry relationship between
N
a
2
O and NaOH. as 1:2
It means 1 moles of
N
a
2
O is required to react with one mol of
H
2
O to produce 2 moles of NaOH.
in terms of mass 1 mole of
N
a
2
O has mass 62 g on reaction with water produces 2 moles of NaOH or 80 g of NaOH.
62 g of
N
a
2
O produces 80 g of NaOH.
1g of NaOH is produced from 62/80 g of
N
a
2
O
1.6 x
10
2
g of NaOH will require 62 x 1.6 x
10
2
g / 80 of
N
a
2
O
124g of
N
a
2
O.
Explanation:
Neon is a noble gas because it is stable non reactive and has ____ valence electrons
Answer:
8 .....................
what is the formula for the compound potassium chloride?
Answer:
KCl
Explanation:
hope this is correct and helps i did this last year in chem :)
[tex]\mathrm{KCl}[/tex]
Anyone know how to do this?
Answer:I can’t see the question
Explanation:
Which of the following questions will allow you to determine if a population of organisms are MOST LIKELY a result of natural or artificial selection? A. How similar are the organisms to their parents? B. How many different traits are there in the population of organisms? C. Do the organisms have traits that are valuable to humans but are poorly suited to the wild? D. Were the organisms produced by sexual or asexual reproduction?
Answer:c
Explanation:
Help me please an thank you
Molecular formula
hope that helps^^
What is the formula for copper(I) phosphate(v)
Answer:
Cu3PO4
Explanation:
There are two types of chemical compound one is covalent compound and other is ionic compound, covalent compound formed by sharing of electron and ionic compound formed by complete transfer of electron. Therefore, Cu[tex]_3[/tex]PO[tex]_4[/tex] is the formula for copper(I) phosphate(v).
What is chemical Compound?Chemical Compound is a combination of molecule, Molecule forms by combination of element and element forms by combination of atoms in fixed proportion.
An ionic compound is a metal and nonmetal combined compound. Ionic compound are very hard. They have high melting and boiling point because of strong ion bond. Cu[tex]_3[/tex]PO[tex]_4[/tex] is the formula for copper(I) phosphate(v). Cu[tex]_3[/tex]PO[tex]_4[/tex] is an ionic compound with cation Cu⁺¹ and anion as PO₄³⁻.
Therefore, Cu[tex]_3[/tex]PO[tex]_4[/tex] is the formula for copper(I) phosphate(v).
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HELPP PLEASEEEEEEEEEEEEE
Answer:
Potential energy I believe
Explanation:
How is a gamete different from other types of cells in a person's body?
There are three main parts to any dissolution which result in an energy change, either endothermic or exothermic. Consider the dissolution of sodium chloride and explain what each of these three major energy changes are.
Answer:
The dissolution of sodium chloride involves three steps. During the process energy changes occur in:
1. breaking apart the hydrogen bonds between water molecules,
2. breaking apart the electrostatic bonds between sodium and chloride ions, and
3. when bonds are formed between water molecules and aqueous ions in solution.
Since the energy used to break apart the hydrogen bonds between water molecules and the energy used to break apart the electrostatic bonds between sodium and chloride ions, is greater than the energy released when bonds are formed between water molecules and aqueous ions in solution, the dissolution of sodium chloride is endothermic.
Explanation:
The heat of solution or enthalpy of solution/dissolution, is the enthalpy change that occurs with the dissolution of a solute in a solvent at constant pressure, resulting in infinite dilution. Its unit is kJ/mol for reactions taking place under standard conditions (298.15 K and 1 atm).
The process of dissolution occurs in three energy-dependent steps:
1. The breaking of bonds within the solute. For example, electrostatic forces of attraction between two oppositely-charged ions. This process is endothermic.
2. The endothermic process of breaking of intermolecular forces within the solvent, e.g. hydrogen bonds in water.
3. The exothermic process of the formation of new solute-solvent bonds in solution.
The sum of the energies involved in these three steps gives the enthalpy of dissolution of a solute. The overall process of dissolution can either endothermic or exothermic depending on the amount of energy used or released in breaking and making bonds. If more energy is released in making than is used in breaking bonds, it is exothermic. However, if more energy is used in breaking bonds than is released in making bonds, dissolution is then endothermic.
For example, considering the dissolution of sodium chloride. During the process the energy used to break apart the hydrogen bonds between water molecules and the energy used to break apart the electrostatic bonds between sodium and chloride ions, is greater than the energy released when bonds are formed between water molecules and aqueous ions in solution. Therefore, the dissolution of sodium chloride is endothermic.
The solubility of AgNO3 at 10° and 20°C are 170g and 222g per 100g H2O. What is the sign of change of heat of solution for AgNO3?
Answer:
The sign of change of heat of solution is positive
Explanation:
The dissolution of AgNO3 in water is represented by the equation;
AgNO3(s) --------> Ag^+(aq) + NO3^-(aq)
We can see from the question that as the temperature was increased from 10° to 20°C the solubility of the solute increased from 170g to 222g per 100g of H2O.
This implies that the solubility of the solute increases with increase in temperature.
If a reaction moves in the forward direction when the temperature is increased, then the reaction is endothermic. If the reaction is endothermic, the sign of change of heat of solution is positive.
what's the formula for hypoarsenous acid?
Answer:
As(OH)3 or AsH3O3
Explanation:
Explain why dissolving is classified as a physical change.
Answer:
dissolving is classified as a physical change because it can be reversed back to its original form
explanation:
Dissolving is an example of a reversible change. For example, when salt is mixed with water it disappears because it dissolves in the water to make salty water. But we can get the salt can back again by boiling off the water. That leaves the salt behind.
A lens is an instrument that can combine and focus light to a single point. The diagram below shows many different colors of light entering a lens and focusing on Point X. Which of the following BEST describes the effect the lens has on Point X?
Answer:
it should be the second one :)
Explanation: