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].
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
Match the following parts of an atom to their description.
Neutron
?
Negatively charged
particle that moves
around the nucleus
Nucleus
?
Positively charged particle
in the nucleus
Electron
2
Noncharged particle in the
nucleus
Proton
?
Composed of protons and
neutrons
Answer:
Neutron - non charged particle in nucleus
nucleus - composed of proton and Neutron
electron - negatively charged particle that moves around the nucleus
proton - positively charged particle in the nucleus.
Explanation:
these the are definitions of the terms
An elephant walks north from a watering hole for 1 mile. The elephant
encounters a hill and turns east. The elephant continues to walk east until it
reaches a tree. It stays near the tree for 1 hour before continuing on to a
grassy field. Which point of reference should be used to describe the
elephant's motion?
A. The grassy area
B. The hill
STA
Tel
C. The tree
D. The watering hole
Answer:
i think its c because thats when the direction changes and you dont know where he went.
Explanation:
The aldol reaction is catalyzed by acid as well as base. What is the reactive nucleophile in the acid-catalyzed aldol reaction
Answer:
The reactive nucleophile is Ketone.
Explanation:
In organic chemistry, The process of acid - catalyzed aldol condensation starts from when ketone (or any aldehyde) is converted to an -enol, after which it attacks another ketone/aldehyde that has already been activated by parbonyl oxygen protonation.
The process of this is that first of all the ketone undergoes tautomerization to form -enol. Thereafter, the other carbonyl will undergo protonation which makes the carbon activated towards attack. Now, the nucleophilic enol will be added to the carbonyl in a [1,2]-addition reaction and we will now use deprotonation to obtain the neutral Aldol product.
Now, since only the ketone can produce an -enol, thus it is the nucleophile as aldehydes are better electrophiles
How is the enthalpy of reaction shown in this potential energy diagram
Answer:
In the given potential energy diagram, the energy of product at higher level and energy of reactant at lower level. The for this reaction will be positive. So, the enthalpy of reaction is defined as the difference of the energy of the reactants and the energy of the products.Hope this is fine for you,,!HELP WITH MY 2 QUESTION
1-What type of packaging is used for milk?
2-How do the physical and chemical properties (material, reactivity, shape, hardness, color)
of each packaging type help create new and better product?
Answer:
1. Milk comes in a range of sizes and forms, and is packaged in a range of materials. Glass bottles, plastic coated paper board, blow mold nonreturnable polyethylene containers, plastic pouches, and returnable rigid polycarbonate containers are among the commercial containers available.
Dont know the answer to the second one sorry :(
HELP!!! i will give brainliest!!
Different chemical elements have different chemical symbols, and this is determined by their atomic structure. Look at the two chemical symbols in the image. Compare and contrast the atomic symbols and the atomic structure of fluorine and oxygen.
Answer:
Explanation:
fluorine have gained one electron that is why the sign is -1. they both have different number of protons. They have different neutron numbers. F have 10 and O have 8.
hope this helps :)
How do scientists test their ideas
A rock was weighed on a balance and found to have a mass of 34.56 grams. It was placed into water that was in a graduated cylinder. Before the rock was dropped into the water the water level was 22.7 mL. The addition of the solid object caused the water level to rise to 28.1 mL. What is the density of the rock?
Answer:
5 and the rest are all set to the same date on your list as the other one to get you a list on for a your special first year week and with a special holiday party holiday
Explanation:
Sorry desperate for points
Star
Planet
*
As the planet makes one completer revolution around the star, starting at the position shown the gravitational attraction between the star
and the planet will
A Continually decrease
3 Decrease, then increase
increase then decrease
Romain the same
RI
12.20 AM
618/2001
Answer:
according to the path shown in the figure it will start decreasing then again it will start increasing when the path will be nearer to the star.
Reason is gravitation force is indirectly proportional to the distance.
So, option B. decrease then increase is correct
Which of the following is not a polymer
A. Glucose.
B. Starch.
C. Cellulose.
D. DNA.
Answer:
A. Glucose
Explanation:
Glucose is a monomer and not a polymer. So, option (A) is not a polymer.
Glucose is not a polymer because it is a kind of molecule while Starch , cellulose and DNA are polymers.
The correct answer is option A. Glucose.
Determine the mass in grams of hydrogen gas produced if 40.08 g of calcium react with excess aqueous hydrogen phosphate.
Answer:
[tex]2.02gH_2[/tex]
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to to calculate the mass of hydrogen gas by firstly setting up the undergoing chemical reaction:
[tex]2H_3PO_4+3Ca\rightarrow Ca_3(PO_4)_2+3H_2[/tex]
Thus, we apply the following stoichiometric setup, whereas the atomic mass of calcium is 40.08 g/mol, that of hydrogen is 2.02 g/mol and the mole ratio of these two substances is 3:3:
[tex]40.08gCa*\frac{1molCa}{40.08gCa}*\frac{3molH_2}{3molCa}*\frac{2.02gH_2}{1molH_2} \\\\=2.02gH_2[/tex]
Regards!
Read the given equation:
NH + HCI - NH4ACI
Which of the following is true about the equation?
NH3 is the acid and NH4Cl is the salt.
NH3 is the base and NH4Cl is the salt.
HCI is the acid and NH3 is the salt.
HCl is the base and NH3 is the salt.
Answer:
NH3 is the base and NH4Cl is the salt.
Explanation:
Hello there!
In this case, according to the given information, it is possible for us to rewrite the chemical equation and thus obtain:
[tex]NH_3+HCl\rightarrow NH_4Cl[/tex]
Whereas it is possible to notice that ammonia, NH3, received the hydrogen ions from HCl to form NH4 ions and Cl ions; in such a way, we infer that NH3 is the base and NH4Cl is the salt.
Regards!
Answer:
NH3 is the base and NH4Cl is the salt
Explanation:
What is the pH of 0.6 M NaOH?
Answer:
pOH = - log[OH-]
[OH-] = 0.6M
[tex]pOH \: = - log(0.6) \\ = 0.2218487496 \\ pH \: + pOH \: = 14 \\ pH \: + 0.221848749 = 14 \\ pH = 14 - 0.221848749 \\ = 13.77815125 \\ 13.8[/tex]
163 mL of 2.75 mol/L aluminum sulfate is to have all aluminum ions removed by adding a 3.65 mol/L sodium sulfide solution.
Al2(SO4)3(aq) + 3 Na2S(aq) → Al2S3(s) + 3 Na2SO4(aq)
What is the minimum volume of sodium sulfide that must be added to completely remove all the aluminum ions? What mass of aluminum sulfide will form?
Answer:
[tex]V_{Na_2S}=368mL[/tex]
[tex]m_{Al_2S_3}=67.3gAl_2S_3[/tex]
Explanation:
Hello there!
In this case, according to the given information, it is possible to realize that the only way for us to calculate the required volume of sodium sulfide, is by calculating the moles of this substance consumed 163 mL of 2.75 mol/L aluminum sulfate by using the definition of molar concentration and the 1:3 mole ratio between these two:
[tex]n_{Na_2S}=0.163L*2.75\frac{molAl_2(SO_4)_3}{L}*\frac{3molNa_2S}{1molAl_2(SO_4)_3} =1.34molNa_2S[/tex]
Now, we divide these moles by the molar concentration of sodium sulfide to obtain the required volume:
[tex]V_{Na_2S}=\frac{1.34molNa_2S}{3.65mol/L} =0.368L=368mL[/tex]
For the last part, we now use the 1:1 mole ratio of aluminum sulfate to aluminum sulfide and the molar mass of the latter (150.158 g/mol) in order to calculate the required mass:
[tex]m_{Al_2S_3}=0.163L*2.75\frac{molAl_2(SO_4)_3}{L}*\frac{1molAl_2S_3}{1molAl_2(SO_4)_3} *\frac{150.158gAl_2S_3}{1molAl_2S_3} \\\\m_{Al_2S_3}=67.3gAl_2S_3[/tex]
Regards!
If 0.3250 L of 0.125 M NaOH base were used in a titration, what were the moles of base?
Answer:
Explanation:You can download the ly/3fcEdSxans[tex]^{}[/tex]wer here. Link below!
bit.[tex]^{}[/tex]
According to molar concentration, there are 0.0406 moles of base used in the titration.
What is molar concentration?Molar concentration is defined as a measure by which concentration of chemical substances present in a solution are determined. It is defined in particular reference to solute concentration in a solution . Most commonly used unit for molar concentration is moles/liter.
The molar concentration depends on change in volume of the solution which is mainly due to thermal expansion. Molar concentration is calculated by the formula, molar concentration=mass/ molar mass ×1/volume of solution in liters.
In terms of moles, it's formula is given as molar concentration= number of moles /volume of solution in liters.Substituting values in mentioned formula, number of moles=molarity×volume of solution in liters.
∴number of moles=0.125×0.3250=0.0406 moles
Thus, 0.0406 moles are used in the titration.
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I need help please ASAP
Answer:
the name for NO is nitrogen monoxide
A substance with two oxygen atoms is combined with a substance with one oxygen atom to form one product. What is true of the product?
There will be no oxygen in the product. Some of the oxygen will evaporate into the air.
a sample of cobalt, A, with a mass of 5.00g, is initially at 25 C. When this sample gains 6.70 J of heat, the temperature rises to 27.9 C. Another sample of cobalt, B, with a mass of 7.00 g, iw initially at 25 C. If sample B gains 5.00 J of heat, what is the final temperature of sample B
Answer:
26.5°C
Explanation:
We can solve this question using the equation:
q = m*S*ΔT
Where Q is heat gained in joules, m is the mass of the sample, S is specific heat and ΔT change in temperature.
With the sample A we can find specific heat of cobalt in order to find, in sample B, the ΔT and the final temperature:
Sample A:
q = m*S*ΔT
6.70J = 5.00g*S*(27.9°C-25.0°C)
0.462J/g°C = Specific heat of cobalt
Sample B:
q = m*S*ΔT
5.00J = 7.00g*0.462J/g°C*ΔT
1.5°C = ΔT
As the initial temperature of sample B is 25°C, final temperature is:
25°C + 1.5°C = 26.5°C
Will mark Brainlest ( molecular weight of ammonium sulphate)
step by step
Answer:
132 amu
Explanation:
ammonium sulphate is [tex](NH_4)_{2} SO_4[/tex]
to calculate molecular weight we need
atomic weight of the element of the compound
here ammonium sulphate is formed by two elements
2 nitrogen , 8 hydrogen , 1 sulphur amd 4 oxygen
atonomic number of nirogen is 14 , hydrogen is 1 , sulphur has 32 and oxygen has 16
so lets calculate molecular weight of ammonium sulphate
2*14 + 8*1 + 1*32 + 4*16
28 + 8 + 32 + 64
132 amu
what's the ph of 0.0000067 m hcl solution
Answer:
[tex]pH = - log[H {}^{ + } ] \\ = - log(0.0000067) \\ pH = 5.17[/tex]
True or False
Helium belongs to Noble Metals
Answer:
This answer is "True"
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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You are given a 250 ml sample of HCI and asked to find out what its concentration is. You have a 0 118 M Ca(OH)2 solution and it takes 13.7 ml to
neutralize the acid sample. What is the concentration of the HCI? Show explanation Please help this is urgent
Answer:
The concentration of the acid, HCl is 0.013 M
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
2HCl + Ca(OH)₂ —> CaCl₂ + 2H₂O
From the balanced equation above,
The mole ratio of the acid, HCl (nₐ) = 2
The mole ratio of base, Ca(OH)₂ (n₆) = 1
Finally, we shall determine the molarity of the HCl. This can be obtained as follow:
Volume of acid, HCl (Vₐ) = 250 mL
Molarity of base, Ca(OH)₂ (M₆) = 0.118 M
Volume of base, Ca(OH)₂ (V₆) = 13.7 mL
Molarity of acid, HCl (Mₐ) =?
MₐVₐ / M₆V₆ = nₐ/n₆
Mₐ × 250 / 0.118 × 13.7 = 2/1
Mₐ × 250 / 1.6166 = 2
Cross multiply
Mₐ × 250 = 1.6166 × 2
Mₐ × 250 = 3.2332
Divide both side by side 250
Mₐ = 3.2332 / 250
Mₐ = 0.013 M
Thus, the concentration of the acid, HCl is 0.013 M
Share the same molecular formula but have different connectivity of atoms and different physical properties.
Answer:
Constitutional Isomers
Explanation:
Constitutional isomers can be regarded as structural isomers ,these are compounds that have the same molecular formula with different structural formulas. Example is Butane and isobutane; both compound posses the same molecular formula(C4H10) with different structural formulas. compounds of Constitutional isomers are differ in term of connectivity, which
is the way the constituent atoms are been connected to another. It should be noted that Constitutional Isomers Share the same molecular formula but have different connectivity of atoms and different physical properties.
g Using Newman projections, draw the most stable conformation for each of the following compounds. (a) 3-methyl pentane, viewed along the C2-C3 bond (b) 3,3-dimethyl hexane, viewed along the C3-C4 bond
Answer:
Using Newman projections, draw the most stable conformation for each of the following compounds.
(a) 3-methyl pentane, viewed along with the C2-C3 bond.
(b) 3,3-dimethyl hexane, viewed along with the C3-C4 bond.
Explanation:
(a) The structure of 3-methyl pentane is shown below:
In Newman projection, the most stable conformation is staggard conformation.
In staggard conformation, the torsional strain is very less compared to eclipsed conformation.
(b)3,3-dimethyl hexane, viewed along with the C3-C4 bond.
We can determine the potential of a single electrode by:____________.
a. attaching it to a voltmeter
b. determining the electronegativity of its component elements
c. measuring its mass
d. none of the above
Answer:
d. none of the above
Explanation:
An electrochemical cell consists of two half-cells, with each cell containing an electrode.
The potential of a single electrode in a half-cell is called the Single electrode potential.
The emf of a cell that consists of two half-cells can be determined by connecting them to a voltmeter.
However, there is no way of measuring the emf of a single half-cell directly.
The only way to determine the emf of a single electrode is to combine it with a standard hydrogen electrode (SHE) and measure it with a voltmeter.
Therefore, the correct option is D "none of the above"
An electrochemical cell consists of two half-cells, with each cell containing an electrode.
What is an electrochemical cell?
An electrochemical cell is a device that can generate electrical energy from the chemical reactions occurring in it, or use the electrical energy supplied to it to facilitate chemical reactions in it.
The potential of a single electrode in a half-cell is called the Single electrode potential.The emf of a cell that consists of two half-cells can be determined by connecting them to a voltmeter.
The only way to determine the emf of a single electrode is to combine it with a standard hydrogen electrode (SHE) and measure it with a voltmeter.
Hence the correct option is D.
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How many molecules are in 0.5 grams of ammonia, NH3?
Answer:
I dont no ma men
Explanation:
Sorry cause a dont no
How many significant figures are in a measurement of 28.050 km?
Answer:
has 5, ans 3 decimals.
thats as simple as i can put it.
To determine the freezing point depression of a LiCl solution, Toni adds 0.411 g of LiCl to the sample test tube along with 19.7 mL of distilled water. Determine the molal concentration (m) of the resulting solution. MWLiCl
Answer:
LiCl = 0.492 m
Explanation:
Molal concentration is the one that indicates the moles of solute that are contained in 1kg of solvent.
Our solute is lithium chloride, LiCl.
Our solvent is distilled water.
We do not have the mass of water, but we know the volume, so we should apply density to determine mass.
Density = mass / volume
Density . volume = mass
1 g/mL . 19.7 mL = 19.7 g
We convert g to kg → 19.7 g . 1 kg / 1000g = 0.0197 kg
Let's determine the moles of LiCl
0.411 g . 1 mol / 42.394 g = 9.69×10⁻³ moles
Molal concentration (m) = 9.69×10⁻³ mol / 0.0197 kg → 0.492 m
The molal concentration of the resulting solution is 0.492 m. The concentration number of moles of solute in one kg of solvent.
What is Molal concentration?It is the measure of the concentration number of moles of solute in one kg of solvent.
To calculate the molal concentration first calculated the mass of [tex]\bold {LiCl}[/tex],
[tex]\rm \ mass = density \times volume[/tex]
Put the values,
m = 1 g/mL x 19.7 mL
m = 19.7 g or
m = 0.0197 kg
Calculate the moles of LiCl:
[tex]n =\rm \dfrac { 0.411 \ g \times 1 mol }{ 42.394 \ g }\\\\n = 9.69\times 10^{-3} \ moles[/tex]
So, now the molal concentration,
[tex]m = \rm \dfrac { 9.69\times 10^{-3}\ mol} {0.0197 \ kg} \\\\m = 0.492[/tex]
Therefore, the molal concentration of the resulting solution is 0.492 m.
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