Answer:
79.1g of weak base must be combined with 56.0g of conjugate acid
Explanation:
that is 1.00 M in the weak base?
The weak base is C5H5N with a pKa of 5.17 (Ka=6.7×10-6)and a desire pH of 5.63
The equilibrium of the weak base is with the bromide salt of the conjugate acid is:
C5H5N(aq) + H2O(l) + Br- ⇄ C5H5NHBr(aq) + OH-(aq)
Where Kb = Kw / Ka = 1x10⁻¹⁴ / 6.7x10⁻⁶
Kb = 1.49x10⁻⁹ is defined as:
Kb = 1.49x10⁻⁹ = [C5H5NHBr] [OH-] / [C5H5N]
Where [OH-] = 10^-(14- pH) = 10^-(14- 5.63) = 4.255x10⁻⁹M
[C5H5N] = 1.00M
Replacing:
1.49x10⁻⁹ = [C5H5NHBr] [OH-] / [C5H5N]
1.49x10⁻⁹ = [C5H5NHBr] [4.255x10⁻⁹M] / [1.00M]
[C5H5NHBr] = 0.35M
In 1L the moles of C5H5NHBr are 0.35 moles
Mass C5H5NHBr: 160.0118g/mol
0.35 moles * (160.0118g / mol) =
56.0g of C5H5NHBr are necessaries
The mass of C5H5N is -79.1g/mol-:
1.00moles * (79.1g/mol) =
79.1g of C5H5N are necessariesHELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Which of the following statements is true?
Some plants cannot reproduce.
Pollen contains male sperm cells.
Mitosis results in two non-identical cells.
Flowering plants reproduce using spores.
Answer:
errccvbnnbb
Explanation:
jjuxxxsyy
Answer:
i think it the third one
Explanation:
sorry if im wrong are u in biology?
please help me with Chem I ONLY HAVE 5 MINUTES if methane gas (CH4) flows at a rate of 0.25L/s, how many grams of methane gas will there be in a room after 1 hour of time has passed?
Answer:
643g of methane will there be in the room
Explanation:
To solve this question we must, as first, find the volume of methane after 1h = 3600s. With the volume we can find the moles of methane using PV = nRT -Assuming STP-. With the moles and the molar mass of methane (16g/mol) we can find the mass of methane gas after 1 hour as follows:
Volume Methane:
3600s * (0.25L / s) = 900L Methane
Moles methane:
PV = nRT; PV / RT = n
Where P = 1atm at STP, V is volume = 900L; R is gas constant = 0.082atmL/molK; T is absolute temperature = 273.15K at sTP
Replacing:
PV / RT = n
1atm*900L / 0.082atmL/molK*273.15 = n
n = 40.18mol methane
Mass methane:
40.18 moles * (16g/mol) =
643g of methane will there be in the roomHELP ME ASAP PLEASE
I need the answers I’m in a hurry
Answer: First box----Hail
Second Box-------Snow
Thrid Box-------Sleet
Forth Box-----Rain
Hope that helped! :)
What piece of apparatus could be used to measure the volume of gas produced in a reaction
1)beaker
2)gas syringe
3) top pan balance
Answer: 2)gas syringe
Explanation:
the volume of a gas is usually measured with a gas syringe (or sometimes with an upside-down measuring cylinder)
Answer:
top pan balance
Explanation:
When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(II) sulfate PbSO4 is reduced to lead at the cathode and oxidized to solid lead(II) oxide PbO at the anode.Suppose a current of 62.0 is fed into a car battery for 23.0 seconds. Calculate the mass of lead deposited on the cathode of the battery. Round your answer to 3 significant digits. Also, be sure your answer contains a unit symbol.
Answer: The mass of lead deposited on the cathode of the battery is 1.523 g.
Explanation:
Given: Current = 62.0 A
Time = 23.0 sec
Formula used to calculate charge is as follows.
[tex]Q = I \times t[/tex]
where,
Q = charge
I = current
t = time
Substitute the values into above formula as follows.
[tex]Q = I \times t\\= 62.0 A \times 23.0 sec\\= 1426 C[/tex]
It is known that 1 mole of a substance tends to deposit a charge of 96500 C. Therefore, number of moles obtained by 1426 C of charge is as follows.
[tex]Moles = \frac{1426 C}{96500 C/mol}\\= 0.0147 mol[/tex]
The oxidation state of Pb in [tex]PbSO_{4}[/tex] is 2. So, moles deposited by Pb is as follows.
[tex]Moles of Pb = \frac{0.0147}{2}\\= 0.00735 mol[/tex]
It is known that molar mass of lead (Pb) is 207.2 g/mol. Now, mass of lead is calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\ 0.00735 = \frac{mass}{207.2 g/mol}\\mass = 1.523 g[/tex]
Thus, we can conclude that the mass of lead deposited on the cathode of the battery is 1.523 g.
What is the the heat of reaction, delta, in kJ/mol?
a) -26kJ/mol
b) -25kJ/mol
c) -10kJ/mol
d)-35kJ/mol
Answer:
b) -25 kJ/mol.
Explanation:
Hello there!
In this case, since the general definition of the enthalpy of reaction involves the subtraction of the energy of the products and the energy of the reactants:
[tex]\Delta H=H_{prod}-H_{react}[/tex]
Thus, since the graph shows that the energy of the products is 20 kJ/mol and that of reactants 45 kJ/mol, we will obtain:
[tex]\Delta H=20kJ/mol-45kJ/mol\\\\\Delta H=-25kJ/mol[/tex]
Which means it is exothermic.
Regards!
Name the following alkene:
CH3CH = CHCH2CH3
A. 3-pentane
B. 2-pentene
C. 2-pentane
D. 3-pentene
Answer:
2-pentene
Explanation:
The name of the alkene is 2 pentene. The correct option is B, 2-pentene.
What is 2-pentene?Alkenes with the chemical formula [tex]C_5H_10[/tex] are known as pentene. Within its molecular structure, each has one double bond.
The given alkene [tex]CH_3CH = CHCH_2CH_3[/tex] is 2-pentene because the double bond is present in the second carbon and it's pentene because there are five carbons present.
Thus, the correct option is B. 2-pentene.
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12 points
Methyl methacrylate has a molar mass of 100 g/mole When a sample of methyl methacrylate weighing 3.14 g was completely combusted, the only products formed
were 6.91 g of CO2 and 2.26 g of water. What is methyl methacrylate's molecular formula?
O A C5H8O2
OBC6H120
OCC7H16
OD. None of the above
O E C4H403
Answer:
C₅H₈O₂
Explanation:
methyl methacrylate = 100 amu
6.91g CO₂ = 0.157 moles
2.26g H₂O = 0.125 moles
0.157 ÷ 0.125 = 1.256
{(CO₂)₁.₂₅₆ + (H₂O)₁} × 4 = (CO₂)₅ + (H₂O)₄
C₅H₈O?
C₅ = 60.05 amu H₈ = 8.064 amu
60.05 + 8.064 = 68.114 amu
100 amu - 68.114 amu = 31.886 amu
O = 16 amu
O = 2
The molecular formula of methyl methacrylate is C₅H₈O₂. The correct option is A, C₅H₈O₂.
What is methyl methacrylate?
Methyl methacrylate (MMA) is a colorless liquid monomer with a distinctive fruity odor. It is an organic compound that belongs to the family of acrylic esters.
We have to determine the empirical formula of methyl methacrylate first and then multiply it by the integer n to determine the molecular formula. Empirical formula:
CO₂ and H₂O are the combustion products of methyl methacrylate.
C₅H₈O₂ + (9n / 2)
O₂ → 5CO₂ + (n)H₂O
There are 5 C atoms and (8 + 2n), H atoms in the left and 5 C atoms, and n H atoms in the right.
5C = 5C, and 8 + 2n = nH.
n = 6
Molecular formula calculation is dividing the molecular weight by the empirical formula weight to determine the multiplication factor.
C₅HₙO₂ (empirical formula) has a weight of:
(5 x 12.011) + (8 x 1.008) + (2 x 15.999) = 100.12 g/mol
The actual molecular weight of methyl methacrylate is 100 g/mol.
Therefore, the molecular formula is (C₅H₈O₂) x 1, which is C₅H₈O₂, option A.
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Carbon dioxide had how many nonbonding electron pairs in its electron arrangement?
A. 2
B. 4
C. 8
D. 6
E. 3
Answer: A.) 2 is the answer.
Explanation:
If 15L of neon is at 25C is allowed to expand to 45L. What is the new temperature to maintain constant pressure?
Answer:
[tex]T_2=894.45K=621.30\°C[/tex]
Explanation:
Hell there!
In this case, according to the given information, it turns out possible for us to calculate the new temperature by applying the Charles' law as a directly proportional relationship between temperature and volume:
[tex]\frac{V_2}{T_2} =\frac{V_1}{T_1}[/tex]
Thus, we solve for the final temperature, T2, as shown below (make sure T1 is in Kelvins):
[tex]T_2=\frac{V_2T_1}{V_1} \\\\T_2=\frac{(25+273.15)K*45L}{15L}\\\\T_2=894.45K=621.30\°C[/tex]
Regards!
A substance in a specific state of matter with volume of 6 liters was transferred to a 12 liter container. The substance took up the
A. It is highly compressible.
B. It also has a definite shape.
C.Its particles slide past one another
D. Its intermolecular forces are of high strength.
[tex]\huge\color{yellow}\boxed{Answer:}[/tex]
My answer is C.Its particles slide past one another
[tex]\huge\color{yellow}\boxed{toshiro hitsugaya}[/tex]
When the 6 liters volume of the substance takes up 12 liter container, we conclude that the substace is highly compressible.
What is compressibility?
Compressibility is the measure of the relative volume change of a solid or a fluid with respect to pressure change.
Gases are the most compressible susbtance because most of the volume of a gas is composed of the large amounts of empty space between the gas particles.
Therefore, when the 6 liters volume of the substance takes up the entire volume of 12 liter container, we can conclude that the substace is highly compressible.
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Which best explains the relationship between evaporation and temperature?
• A liquid evaporates slower at lower temperatures because the molecules are more spread apart and are not pushed
as easily from the liquid's surface.
O A liquid evaporates faster at lower temperatures becaus the attractions are decreased and more particles can
escape the surface of the liquid.
© A liquid evaporates slower at higher temperatures because the vapor pressure of the liquid is higher, SO fewer
molecules can escape the surface.
• A liquid evaporates faster at higher temperatures because more particles have a higher speed and can overcome
attractions in the liquid.
Answer: D
Explanation:
liquid evaporates faster at higher temperatures because more particles have a higher speed and can overcome attractions in the liquid.
Answer:
D. A liquid evaporates faster at higher temperatures because more particles have a higher speed and can overcome attractions in the liquid.
Explanation:
Correct on Edge 2022!!!
Good luck everyone, you got this! Have a great day!
If it takes 720. mL of 0.00125 M Mg(OH)2 to neutralize 425 mL of an HCI
solution, what is the concentration of the HCI? Mg(OH)2 + HCl →MgCl2
+ H20
Answer:
0.004235 M
Explanation:
The neutralization reaction of this question is given as follows:
Mg(OH)2 + 2HCl → MgCl2 + 2H2O
Using the formula below:
CaVa/CbVb = na/nb
Where;
Ca = concentration of acid (M)
Cb = concentration of base (M)
Va = volume of acid (mL)
Vb = volume of base (mL)
na = number of moles of acid = 2
nb = number of moles of base = 1
From the information provided in this question;
Ca = ?
Cb = 0.00125 M
Va = 425 mL
Vb = 720 mL
na (HCl) = 2
nb = (Mg(OH)2) = 1
Using the formula; CaVa/CbVb = na/nb
Ca × 425/0.00125 × 720 = 2/1
425Ca/0.9 = 2
472.2Ca = 2
Ca = 2/472.2
Ca = 0.004235 M
How many ions are in 1
mole of potassium sulfate?
Answer:
We will need two potassium ions to balance the charge on the sulfate ion, so the proper chemical formula is K 2SO 4.
Explanation:
hope this helps
When a balloon containing 635 mL of air is taken from sea level (at standard pressure) to a higher altitude, the balloon expands to 829 mL. What is the air pressure at this new altitude (in atm)?
Answer:
0.766atm
Explanation:
Boyles law
P1V1=P2V2
1×635=P2×829
P2=635/829
P2=0.766atm
is a glow stick Endothermic or exothermic ?
Answer:
exothermic
Explanation:
Pbo.....
= 2Pb +......
Answer:
It's
Explanation:
Pbo + c
= pb + co2
While balancing it becomes
2pbo + c = 2pb + co2
(I was also doing same qn)
sodium is an inactive metal why
Answer:
Inactive metals are inert metals that doesn’t react with most of the chemicals.They are highly resistant to oxidation and corrosion when exposed to moisture.
Explanation:
What is the thermal efficiency of an engine that takes n moles of diatomic ideal gas through the cycle
Answer:
The thermal efficiency of an engine is [tex]0.15[/tex] that is 15%
Explanation:
Specific heat of a gas at constant volume is
[tex]C_{v}=\frac{fR}{2}[/tex]
here, [tex]f=[/tex]degree of freedom
[tex]R=[/tex]universal gas constant
Thermal efficiency of a cycle is
[tex]\frac{total workdone}{gross heat absorbed}[/tex]
Gross heat absorbed is amount of heat that absorbed.
ω[tex]=P_{o} V_{o}[/tex]
[tex]Q_{AB}=[/tex]Δ[tex]V_{AB}+[/tex]ω[tex]_{AB}[/tex][tex]=nC_{v}(T_{f}-T_{i} )[/tex]
[tex]=n\frac{f}{2}(RT_{f}-RT_{i} )[/tex][tex]=\frac{f}{2}(P_{o}V_{o} )[/tex]
[tex]Q_{BC}=n(\frac{f}{2}+1 )R(T_{f}-T_{i} )[/tex]
[tex]=(\frac{f}{2} +1)(4P_{o}V_{o}-2P_{o}V_{o} )[/tex]=[tex]=(\frac{f}{2}+1)2P_{o}V_{o}[/tex]
[tex]Q_{CD}=-ve and Q_{DA}=-ve[/tex] these 2 are not the part of gross heat
η[tex]=\frac{P_{o}V_{o} }{(\frac{3f}{2}+2 )(P_{o}V_{o})}[/tex]
[tex]=\frac{1}{(\frac{3f}{2}+2 )}[/tex]
For monoatomic gas [tex]f=3[/tex]
η[tex]=\frac{2}{13}[/tex]
[tex]=0.15[/tex]
How many molecules of sodium fluoride (NaF) are found in 7.2 moles of sodium fluoride?
Answer:
well please answer me it's question too after you get it
Explanation:
i am also stucked in that question
No. of molecules of any substance is one mole
= Avogadro's Number = (6.022 x 10^23)
So, no. of molecules in 7.2 moles of sodium fluoride
= 7.2 × (6.022 x 10^23)
= 4.33584^24
Astronauts must be protected from extreme heat while
reentering the Earth's atmosphere. Scientists can use the
engineering design process to help make reentry safer.
You have defined the problem as a need for heat shields to be stronger. What
should be your next step in using the engineering design process to solve the
problem?
O A. Communicate your solution to your team members.
O B. Update your initial design for the heat shield.
O C. Identify the criteria and constraints of the project.
O D. Build a prototype of a possible new type of heat shield.
The next engineering step to be taken is to update your initial design for the heat shield.
What is a heat sheild?The term heat sheild refers to a device that can be used to shield an from astronaut extreme heat especially as they re-enter the earth's atmosphere.
After you have identified the problem, the next engineering step to be taken is to update your initial design for the heat shield.
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Qualitatively explain the effect of changing concentration of Cu2+ on voltage using your experimental observations and the Keq values below. (No calculations are required).
(a) Cu^2+(aq) + 4NH3(aq) ⇄ [Cu(NH^3)4]^2+(aq) Keq = 1.2 x 10^12
(b) CuS(s) ⇄ Cu^2+(aq) + S^2-(aq) , Keq = 8.5 x 10^-45
Cu/Zn = 0.525 V
after 1 drop NH3: 0.505 V
after 2 drops NH3: 0.435 V
Cu/Zn = 0.510 V
after 1 drop Na2S: 0.452 V
after 2 drops Na2S: 0.393 V
You dissolve 14 g of [tex]Mg(NO_{3} )_{2}[/tex] in water and dilute to 750 mL. What is the molarity of this solution?
Show your work
The compound AlP (aluminum phosphide) is a compound semiconductor having mixed ionic and covalent bonding. Calculate the fraction of bonding that is ionic.
Answer:
0.086
Explanation:
The formula for calculating the fraction of a covalent bond can be expressed as:
= exp (-0.25ΔE²)
[tex]= exp[-0.25(E_{Al}-E_{p})^2]---(1)[/tex]
from the equation above;
[tex]E_{Al}[/tex] = the electronegativity of aluminum
[tex]E_P[/tex] = electronegativity of phosphorus
Using the data from periodic table figures;
[tex]E_{Al}[/tex] = 1.5
[tex]E_P[/tex] = 2.1
∴
fraction of the covalent = exp[-0.25(1.5 - 2.1)²]
fraction of the covalent = exp(-0.09)
fraction of the covalent = 0.914
Now, the fraction of ionic bond will be = 1 - the fraction of covalent bond
= 1 - 0.914
∴
the fraction of bond that is ionic = 0.086
A 2.5 M solution of a weak acid is prepared. Using a pH meter, the pH is measured to be 5.1. Calculate the acid ionization constant, [tex]K_{a}[/tex] , of this weak acid.
Show your work
Molarity of acid=2.5M
pH=5.1.
ka=?
Now
We need to write an eqn to show the dissociation of the acid
HA + H2O === H3O+ + A-
Writing The Equilibrium(Or Acid dissociation constant) of this reaction
Ka =[H3O+] {A-]/ {HA].
The concept behind this is
concentration of Products divided by those of reactants. Water is not written because its a pure liquid and does not affect the Equilibrium constant.
Now If you have any Idea on ICE tables..
You'd know that the concentration of acid will decrease by 2.5-x
Whilst the products...will increase by x each
Note: This is when the ratio of their Moles are in 1:1
ka= x.x/2.5-x
Since the Moles of A- and H3O+ are in 1:1... Their concentrations at equilibrium will be the same
so
Ka= x²/2.5-x
Now what is x??
x is the Hydrozonium ion concentration.
we can get it from the pH formula
pH= -log (H3O+)
Making H3O+ subject by applying Logarithm Rules
H3O+ = 10^-ph
x=10^-5.1
=7.94x10^-6.
Now back to Ka
Ka= x²/2.5-x
Ka= (7.94x10^-6)²/2.5-(7.94x10^-6)
Ka= (7.94x10^-6)²/2.4999
Ka= 2.52x10^-11.
Was a Fun One
The ionization constant of this weak acid is [tex]2.52*10^{-11}[/tex]. The values can be substituted in dissociation formula.
What information do we have?
Molarity of acid=2.5M
pH=5.1
To find:
ka=?
Calculation of ionization constant:[tex]HA + H_2O < === > H_3O^+ + A^-[/tex]
The value of dissociation constant will be:
[tex]Ka =[H_3O^+] [A^-]/ {HA][/tex]
The Moles of A- and H3O+ are in 1:1.Their concentrations at equilibrium will be the same.
[tex]Ka= x.x/2.5-x\\\\Ka= x^2/2.5-x\\\\pH= -log (H_3O^+)\\\\H_3O^+ = 10^{-pH}\\\\x=10^{-5.1}\\\\x=7.94*10^{-6}[/tex]
[tex]Ka= x^2/2.5-x\\\\Ka= (7.94*10^{-6})^2/2.5-(7.94*10^{-6})\\\\Ka= (7.94*10^{-6})^2/2.4999\\\\Ka= 2.52*10^{-11}\\\\[/tex]
Thus, ionization constant of this weak acid is [tex]2.52*10^{-11}[/tex].
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NEED HELP ASAP
Question 7 (5 points)
(05.05 MC)
A synthesis reaction takes place when carbon monoxide (CO) and hydrogen gas (H2) react to form methanol (CH3OH). How many grams of
methanol are produced when 7.0 grams of carbon monoxide reacts with excess hydrogen gas? (5 points)
20 grams
7.0 grams
8.0 grams
6.1 grams
Explanation:
Write the balance equation for the reaction taking place:
CO(g) + 2H2(g) ==> CH3OH ... balanced equation
Find the limiting reactant:
moles CO present = 14 g x 1 mol CO / 28 g = 0.5 moles COmoles H2 present = 1.5 g x 2 mol H2 / 2 g = 0.75 moles H2OBecause according to the balanced equation it takes 2 moles H2 for every 1 mole CO, there isn't enough H2, so it is limiting and will dictate how much CH3OH can be made.
Mass of CH3OH produced = 0.75 moles H2 x 1 mol CH3OH / 2 mol H2 x 32 g CH3OH / mol = 12 g CH3OH
how many cats are in the word
Answer: more than 70,00 and most of that population is living on the streets
What happens when an electron moves to a higher energy level?
A. It releases energy of a specific frequency
B. It gains energy in a quantized amount.
C. It loses energy in the form of light.
D. It absorbs photons of many energies
ANSWER: B. It gains energy in a quantized amount.
Answer:
B. It gains energy in a quantized amount.
which best describes the type of titration for the graph below? O strong acid titrated with a strong base
O strong base titrated with a strong acid
O weak acid titrated with a strong base
O weak base titrated with a strong acid
Answer:
B. strong base titration with a strong acid
How many neutrons are in an atom of argon–40?
Answer:
22 neutrons
Explanation:
If so please sorry