Solution :
The equation is :
[tex]$HA (aq) + NaOH(aq) \rightleftharpoons NaA(aq) + H_2O(l)$[/tex]
The number of the moles of HA os 0.00285, and the volume is 25 mL.
15 mL of the 0.0950 M NaOH is added.
The total volume of a solution is V = 25 mL + 15 mL = 40 mL
The pH of the solution is 6.50
Calculating the [tex]K_a[/tex] of HA
[tex]$HA(aq) \rightleftharpoons A^-(aq)+H^+$[/tex]
[tex]K_a=\frac{[A^-].[H^+]}{[HA]}[/tex]
Let s calculate the concentration of HA and NaOH
[tex]$[HA] = \frac{^nH_A}{V}$[/tex]
[tex]$=\frac{0.00285 \ mol}{0.04 \ L}$[/tex]
= 0.07125 M
[tex]$[NaOH]= \frac{0.015L \times 0.0950 M}{V}$[/tex]
[tex]$=\frac{0.001425 mol}{0.04L}$[/tex]
= 0.0356 M
[tex]$HA(aq) \ \ + \ \ NaOH(aq) \ \ \rightleftharpoons NaA(aq) \\ + \ \ H_2O(aq)$[/tex]
Initial conc. (M) 0.07125 M 0.0356 M 0 M
Change in conc. (M) -0.0356 M -0.0356 M + 0.0356 M
Equilibrium conc. (M) 0.03565 M 0 M 0.0356 M
Therefore, the concentration of HA and the NaA at the equilibrium are [HA] = 0.03565 M and [NaA]= 0.0356 M
0.0356 M of NaA dissociates completely into 0.0356 M [tex]Na^+[/tex] and 0.0356 M [tex]A^-[/tex]
Now for [tex][H^+][/tex]
[tex]$[H^+] = 10^{-pH}$[/tex]
[tex]$=10^{-6.5}$[/tex]
[tex]$=3.16 \times 10^{-7}$[/tex]
Calculating the value of [tex]K_a[/tex],
[tex]K_a=\frac{[A^-].[H^+]}{[HA]}[/tex]
[tex]$=\frac{0.0356 \times 3.16 \times 10^{-7}}{0.03565}$[/tex]
[tex]$=3.16\times 10^{-7}$[/tex]
Therefore the the value of [tex]K_a[/tex] for the unknown acid is [tex]$3.16\times 10^{-7}$[/tex].
A sample of propane, C3Hg, contains 14.4 moles of carbon atoms. How many total moles of atoms does
the sample contain?
Express the total number of moles of carbon and hydrogen numerically.
Answer:
43.2 mol C
115 mol H
158 mol of atoms
Explanation:
Step 1: Given data
Moles of C₃H₈: 14.4 mol
Step 2: Calculate the number of moles of C
The molar ratio of C₃H₈ to C is 1:3. The moles of C are 3/1 × 14.4 mol = 43.2 mol.
Step 3: Calculate the number of moles of H
The molar ratio of C₃H₈ to H is 1:(. The moles of H are 8/1 × 14.4 mol = 115 mol.
Step 4: Calculate the total number of moles of atoms
n = nC + nH = 43.2 mol + 115 mol = 158 mol
Once the race had been completed, the students opened their canisters to see if anything remained inside. They wanted to decide if they should modify their techniques for another race. Designs 1, 2, and 3 all still had some solid Alka-Selzter residue in the canister. Design 4 did not. The teacher asked the students to analyze their results as an engineer would. What worked well in the design? What could be improved? Predict what Design Team 3 decided to change.
A)Use hot water
B)Use more water
C)Not to crush the tablet and to use hot water
D)Not to crush the tablet and to use more water
HURRY! GIVING BRAINLY
Answer:
a
Explanation:because i did the test
Caustic soda, NaOH, can be prepared commercially by the reaction of Na2CO3 with slaked lime, Ca(OH)2. How many grams of NaOH can be obtained by treating 1.350 kg of Na2CO3 with Ca(OH)2
Caustic soda, NaOH, can be prepared commercially by the reaction of Na2CO3 with slaked lime, Ca(OH)2. 1.509 kg of NaOH can be obtained by treating 1.350 kg of Na2CO3 with Ca(OH)2.
what is the function of caustic soda ?Caustic soda means an alkali salt or Lye, which is the common name of sodium hydroxide due corrosive nature of this salt on animal and plant tissues.
It is used in a wide range of applications and the chemical formula of sodium hydroxide is NaOH, used as cleansing agent and also in manufacturing of washing soda.
sodium hydroxide cam also applied as the reagent in the laboratories, preparation of soda lime, used in extraction of aluminum by purifying bauxite.
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How does glue, borax, and water turn into slime, scientifically?
How does glue, borax, and water turn into slime, scientifically?
AnswerIt is the matter of time and WeatherA 10 M concentrated stock solution of NaCl was used to prepare 5 liters of diluted 1 M solution. Which of the following statements is true about the process used to achieve this required dilution?
The volume of stock solution used was less than 0.4 liters.
The volume of stock solution used was more than 5 liters.
The volume of the solvent used was less than 0.4 liters.
The volume of the solvent used was less than 5 liters.
Answer: D.) The volume of stock solution used was more than 5 liters
Explanation:
Answer:
b
Explanation:
i got it
Calcium has 6 different isotopic forms, listed with their fractional composition values, 40Ca-0.96941; 42Ca-0.00647; 43Ca-0.00135; 44Ca-0.2086 ; 46Ca-0.00004; and 48Ca-0.00187. Identify the most and least abundant isotopes of calcium.
Answer:
The most abundant isotope is ⁴⁰Ca and the least abundant is ⁴⁶Ca
Explanation:
The mass, in percentage, of eah isotope of Calcium is their fractional composition multiplied by 100:
40Ca-0.96941*100 = 96.941% of ⁴⁰Ca
42Ca-0.00647*100 = 0.647% of ⁴²Ca
43Ca-0.0013*100 = 0.13% of ⁴³Ca
44Ca-0.02086*100 = 2.086% ⁴⁴Ca
46Ca-0.00004*100 = 0.004% ⁴⁶Ca
48Ca-0.00187*100 = 0.187% of ⁴⁸Ca
That means the most abundant isotope is ⁴⁰Ca and the least abundant is ⁴⁶Ca
4-A major textile dye manufacturer developed a new yellow dye. The dye has a percent composition of 75.95% X, 17.72% N, and 6.33% H by mass with a molar mass of about 240 g/mol. Determine the molecular formula of the dye.
Answer:
C₁₅N₃H₅
Explanation:
Let's assume we have 240 g of the dye (1 mol), in that case we'd have:
240 g * 75.95/100 = 182.28 g of C240 g * 17.72/100 = 42.53 g of N240 g * 6.33/100 = 15.19 g of HNow we convert the masses of each element into moles, using their respective molar masses:
182.28 g C ÷ 12 g/mol = 15.19 mol C ≅ 1542.53 g N ÷ 14 g/mol = 3.04 mol N ≅ 3 15.19 g C ÷ 1 g/mol = 15.19 mol H ≅ 15Thus the molecular formula is C₁₅N₃H₅.
Define how a parasitic relationship between a host and a parasite works.
Answer:
A parasitic relationship is one in which one organism, the parasite, lives off of another organism, the host, harming it and possibly causing death. The parasite lives on or in the body of the host.
Obtain 2 test tubes. 2. Add 2 mL of animal blood plasma into the first test tube a. Use a pH test strip to measure the pH of the blood plasma. ______
Answer:
7.4
Explanation:
Plasma proteins are part of the buffer systems of blood plasma. Plasma contains both positively and negatively charged amino and carboxyl groups. These compounds' charged portions can attract and link hydrogen(H) and hydroxyl ions(OH-), therefore act as buffers.
Plasma serves as a weak and ineffective buffer. The pH of a buffer should always be around 7.4 which is nearly neutral. As such we may deduce from the first experimental observation that there is no change in pH.
what is work and state the law of conservation mass?
Answer:
Work is a force causing the movement or displacement of an object
law of conservation mass:
1. Atoms cannot be created or destroyed in a chemical reaction.
2. Molecules cannot be created or destroyed in a chemical reaction.
3. Compounds cannot be created or destroyed in a chemical reaction.
4. Heat cannot be created or destroyed in a chemical reaction.
Which of the following flows through ecosystems in one direction?
1. Water
2. Energy
3. Nitrogen
4. Carbon
Answer:
It is energy
Explanation:
Your welcome! :)
Energy flows in one direction in an ecosystem.
What is an ecosystem?An ecosystem is a system which shows the interaction between the living organisms and the non-living part of their environment.
An ecosystem usually shows a flow of nutrient and energy
Nutrients are cycled in an ecosystem but energy flows in only one direction.
Therefore, in an ecosystem, energy flows in one direction.
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I NEED THIS NOW AND NO LINKS OR ILL REPORT
Which material creates the most waste and pollutants when creating one
ton of bottles? *
aluminum
glass
plastic
Answer:
plastic
........................
Which particles move randomly and are well spaced out?
Answer:
gas
Explanation:
the force of attraction between the particles of gases is very weak hence the particles of a gas are in constant random motion
when 27 g of water absorbs 1,5000 joules of heat energy the temperature of the water is raised to 57.7 what is the initial temperature of the water
Answer:
The initial temperature of the water is -75.08 K.
Explanation:
Given that,
Mass of water, m = 27 g
Heat absorbed, Q = 1,5000 J
Final temperature of water, T₂ = 57.7 K
The specific heat of water is 4.184 J/g-K
We know that,
[tex]Q=mc\Delta T\\\\Q=mc(T_2-T_1)\\\\\dfrac{Q}{mc}=(T_2-T_1)\\\\T_1=T_2-\dfrac{Q}{mc}[/tex]
Put all the values,
[tex]T_1=57.7-\dfrac{15000}{27\times 4.184 }\\\\=-75.08\ K[/tex]
So, the initial temperature of the water is -75.08 K.
Aerobic respiration is the cellular process in which
A)
oxygen is added to citric acid, providing energy to the cell.
B)
oxygen is added to NAD+ to form NADH.
C)
oxygen is added to an organic fuel, providing energy to the cell.
D)
oxygen is added to ATP, providing energy to the cell.
Answer:
oxygen is add to ATP providing energy to the cell
Use the Hertzsprung-Russell diagram and temperature and luminosity data to identify each star
Answer:
Q:Use the Hertzsprung-Russell diagram and temperature and luminosity data to identify each star
Explanation:
Take it as u please
Answer:
white dwarf- star C
main sequence- star A
giant- Star B
Explanation:
Got it right
Nobelium-259 has a half-life of 58 minutes. If you start with 2,000 grams of nobelium -259how long will it take to have 125 grams of nobelium- 259 left in the sample ?
Answer: 232
Explanation:
Please answer before 3PM C June 7th, 2021. Which statement about the cell theory is correct?
Answer:
Hi, there the answer is D.
Explanation:
which type of chemical bond would be formed between two elements having electron configuration of 1s2 2s2 2p6 3s2 and 1s2 2s2 2p4
Which answer choice shows the correct arrangement of electrons on the energy levels (shells)?
A. 8, 8, 8
B. 2, 8, 2
C. 2, 2, 8
D. 2, 8, 8
Explanation:
looks like c is the answer
Common decay process definition in your own words
Answer:
Your welcome! :)
Explanation:
THE PROCESS IS: Radioactive decay involves the emission of a particle and/or energy as one atom changes into another. In most instances, the atom changes its identity to become a new element.
THE DEFINITION IS: Decay, decompose, rot, putrefy, spoil mean to undergo destructive dissolution. decay implies a slow change from a state of soundness or perfection. a decaying mansion decompose stresses a breaking down by chemical change and when applied to organic matter a corruption.
Please help!!! I"m on a plato mastery test. If you give me an actual answer i will give you brainliest!!!
Identify an element on the periodic table that is chemically similar to boron (B).
The ones that are in red are the possible answers
Answer:
SI
Explanation:
I would say silicon because it is also another metalloid. Boron is a metalloid.
A student sets up the following equation to convert a measurement.
(The stands for a number the student is going to calculate.)
Fill in the missing part of this equation.
Answer:
–0.13 Pa.m²
Explanation:
From the question given above, the following data were obtained:
Measurement (Pa.mm²) = –1.3×10⁵ Pa.mm²
Measurement (Pa.m²) =?
We can convert from Pa.mm² to Pa.m² by doing the following:
1 Pa.mm² = 1×10¯⁶ Pa.m²
Therefore,
–1.3×10⁵ Pa.mm² = –1.3×10⁵ Pa.mm² × 1×10¯⁶ Pa.m² / 1 Pa.mm²
–1.3×10⁵ Pa.mm² = –0.13 Pa.m²
Thus, –1.3×10⁵ Pa.mm² is equivalent to –0.13 Pa.m².
The complete equation will be:
[tex](-1.3\times 10^5 Pa.mm^2)\times 10^{-6}=(-0.13) Pa.m^2[/tex]
Explanation:
Given:
The equation to convert a measurement:
[tex](-1.3\times 10^5 Pa.mm^2)\times ? = ? Pa.m^2[/tex]
To find:
The missing part of the equation.
Solution:
[tex](-1.3\times 10^5 Pa.mm^2)\times ? = ? Pa.m^2[/tex]
On LHS the unit is in [tex]Pa. mm^2[/tex] and RHS the unit is in [tex]Pa.m^2[/tex] which means that we have to convert [tex]mm^2[/tex] to [tex]m^2[/tex]
In 1 millimeter there are 0.001 meters.
[tex]1 mm = 0.001 m\\1 mm^2=0.000001 m^2=10^{-6} m^2[/tex]
So, the complete equation will be:
[tex](-1.3\times 10^5 Pa.mm^2)\times 10^{-6}=(-0.13) Pa.m^2[/tex]
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HELPPP
After 25.3 seconds, the concentration of a starting material
was measured to decrease from 2.00 M to 1.17 M.
Answer:
Rate = 0.83M/s
Explanation:
Rate of a chemical reaction is the 'absolute value' of change in concentration per unit time. That is ...
Rate = |Change in concentration / unit time|
= |Δ[Conc]/Δtime|
= |(1.17M -2.00M) / 25.3s|
= |- 0.83M/s|
= 0.83M/s*
------------
*Note: Some scholars define rate of reaction as a 'scaler' quantity having only magnitude as rate of reaction in a physical sense (up, down, right, left) is not definitive. In physical mechanics, rate is assigned a direction and magnitude of action and becomes a 'vector' quantity.
The speed at which the reaction occurs is called the rate of reaction. The rate of reaction for the decreased concentration is 0.83 M/s.
What is the reaction rate?The reaction rate is the increase or decrease in the concentration of the products per unit of time. The formula for a reaction rate is given as,
[tex]\rm Rate = \rm \dfrac {\text{Change in concentration}} {Unit \; time}[/tex]
Given,
Initial concentration = 1.17 m
Final concentration = 2.00 M
Time = 25.3 sec
Substituting values in the above equation:
[tex]\begin{aligned} &= \dfrac{1.17 - 2.0} {25.3}\\\\&= -0.83\\\\&= 0.83 \;\rm M/s\end{aligned}[/tex]
Therefore, 0.83 M/s is the reaction rate.
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Of the waves shown below, which has the most energy?
Answer:
red it has to be red cuz it is the largest one out of it
Answer:
Apparently its Green
Explanation:
just took the test on A P E X
Calculate the frequency of the green light emitted by a hydrogen atom with a wavelength of 546 nm.
Answer: The frequency of the green light emitted by a hydrogen atom with a wavelength of 546 nm is [tex]5.49 \times 10^{14} s^{-1}[/tex].
Explanation:
Given: Wavelength = 546 nm [tex](1 nm = 10^{-9} m)[/tex] = [tex]546 \times 10^{-9} m[/tex]
The relation between frequency and wavelength is as follows.
[tex]\nu = \frac{c}{\lambda}[/tex]
where,
[tex]\nu[/tex] = frequency
c = speed of light = [tex]3.0 \times 10^{8} m/s[/tex]
[tex]\lambda[/tex] = wavelength
Substitute the values into above formula as follows.
[tex]\nu = \frac{c}{\lambda}\\= \frac{3.0 \times 10^{8} m/s}{546 \times 10^{-9} m}\\= 5.49 \times 10^{14} s^{-1}[/tex]
Thus, we can conclude that the frequency of the green light emitted by a hydrogen atom with a wavelength of 546 nm is [tex]5.49 \times 10^{14} s^{-1}[/tex].
Reaction Progression
Which statement best describes the diagram?
The pathway A-B-D involves a catalyst and is slower than A-C-D.
The pathway A-B-D involves a catalyst and is faster than A-C-D.
The pathway A-C-D involves a catalyst and is slower than A-B-D.
The pathway A-C-D involves a catalyst and is faster than A-B-D
Alkynes do not react directly with aqueous acid as do alkenes, but will do so in the presence of mercury(II) sulfate as a Lewis acid catalyst. The reaction occurs with Markovnikov regiochemistry, so the OH group adds to the more highly substituted carbon and the H adds to the less highly substituted carbon. The initial product of the reaction is a vinyl alcohol, also called an enol. The enol immediately rearranges to a more stable ketone via tautomerization. Draw curved arrows to show the movement of electrons in this step of the mechanism
Answer:
See explanation and image attached
Explanation:
According to Markovnikov regiochemistry, the negative part of the addendum is joined to the more substituted carbon atom. The addition of H-OH to alkynes occurs in the presence of mercury(II) sulfate as a Lewis acid catalyst.
So, the -OH group is added to the highly substituted carbon and the H adds to the less highly substituted carbon.
The enol produced is shown in the mechanism attached to this answer. Rearrangement of this enol form due to keto-enol tautomerism yields the ketone as shown.
Image credit: chemistry steps
The reaction of iron (III) oxide with carbon monoxide produces iron and carbon dioxide.
Fe,O3(s) + 3CO(g) - 2Fe(s) + 3C0 (9)
If you have 39.5g of Fe2O3, how many grams of CO are required for a complete reaction?
Answer:
21g
Explanation:
no.ofmol fe2o3=39.5/(56×2+16×3)=0.25mol
from equation 1mole fe2o3 react with 3mole co
so,0.25mol fe2o3 react with 0.75mol co
mass of co=0.75×(12+16)=21g
Answer:
Approximately [tex]20.8\; \rm g[/tex].
Explanation:
[tex]\rm Fe_2O_3 \, (s) + 3\; CO\, (g) \to 2\; Fe\, (s) + 3\; CO_2\, (g)[/tex].
Relative atomic mass:
[tex]\rm Fe[/tex]: [tex]55.845[/tex].[tex]\rm C[/tex]: [tex]12.011[/tex].[tex]\rm O[/tex]: [tex]15.999[/tex].Formula mass:
[tex]\begin{aligned}M({\rm Fe_2O_3}) &= 2 \times 55.845 + 3 \times 15.999\\ &= 159.687\; \rm g \cdot mol^{-1}\end{aligned}[/tex].
[tex]\begin{aligned}M({\rm CO}) &= 12.011 + 15.999\\ &= 28.010\; \rm g \cdot mol^{-1}\end{aligned}[/tex].
Number of moles of [tex]\rm Fe_2O_3[/tex] formula units in [tex]39.5\; \rm g[/tex] of this compound:
[tex]\begin{aligned}&n({\rm Fe_2O_3}) \\ &= \frac{m({\rm Fe_2O_3})}{M({\rm Fe_2O_3})} \\ &= \frac{39.5\; \rm g}{159.687\; \rm g \cdot mol^{-1}}\approx 0.247\; \rm mol\end{aligned}[/tex].
Refer to the balanced equation for this reaction.
Coefficient of [tex]\rm Fe_2O_3[/tex]: [tex]1[/tex].Coefficient of [tex]\rm CO[/tex]: [tex]3[/tex].Hence, for every formula unit of [tex]\rm Fe_2O_3[/tex] that this reaction consumes, [tex]3\; \rm mol[/tex] of [tex]\rm CO[/tex] molecules would also need to be consumed. Therefore, if neither reactant is in excess:
[tex]\displaystyle \frac{n({\rm CO})}{n({\rm Fe_2O_3})} = \frac{3}{1} = 3[/tex].
Calculate the number of moles of [tex]\rm CO[/tex] required to react with that [tex]39.5\; \rm g[/tex] of [tex]\rm Fe_2O_3[/tex]:
[tex]\begin{aligned}&n({\rm CO}) \\ &= n({\rm Fe_2O_3}) \cdot \frac{n({\rm CO})}{n({\rm Fe_2O_3})} \\[0.5em] &\approx 0.247\; \rm mol \times 3 \approx 0.742\; \rm mol\end{aligned}[/tex].
Make use of the formula mass of [tex]\!\rm CO[/tex] to find the mass of that [tex]0.742\; \rm mol[/tex] of [tex]\rm CO[/tex] molecules:
[tex]\begin{aligned} m({\rm CO}) &= n({\rm CO}) \cdot M({\rm CO}) \\ &\approx 0.742\; \rm mol \times 28.010\; \rm g \cdot mol^{-1} \\ &\approx 20.8\; \rm g\end{aligned}[/tex].
Calculate the pH of a 0.35 mol/L solution of butanoic acid
Answer:
2.6
Explanation:
Step 1: Given and required data
Concentration of butanoic acid (Ca): 0.35 MpKa of butanoic acid: 4.82Step 2: Calculate the acid dissociation constant (Ka) of butanoic acid
We will use the following expression.
pKa = -log Ka
Ka = antilog - pKa
Ka = antilog -4.82 = 1.51 × 10⁻⁵
Step 3: Calculate [H⁺] of the solution
For a weak acid, we can use the following expression.
[H⁺] = √(Ca × Ka)
[H⁺] = √(0.35 × 1.51 × 10⁻⁵) = 2.3 × 10⁻³ M
Step 4: Calculate the pH of the solution
pH = -log [H⁺] = -log 2.3 × 10⁻³ = 2.6