Answer:
0.1795 M
Explanation:
From the given information:
The equation is:
[tex]\mathbf{HF_{(aq)}+ KOH_{(aq)} \to KF _{(aq)} + H_2O}[/tex]
From the above equation, the reaction will go to completion due to the strong base:
At the equivalence point, moles of acid (HF) will be equal to moles of base (KOH)
[tex]\text{Number of moles = Volume} \times Molarity[/tex]
Thus. since moles of HF = moles of KOH
Then; 0.020 × 0.393 M = 0.02379 × (x) M
(x) M = [tex]\dfrac{0.02 \times 0.393 \ M}{0.02379}[/tex]
(x) = 0.3304 M
Thus, the molarity of KOH = 0.3304 M
Using the balanced neutralization reaction;
moles of HF = moles of KOH = moles of conjugate base = 0.00786 mol
∴
Volume = 0.020 L + 0.02379 L
Volume = 0.04379 L
Volume of the solution = 0.04379 L
Therefore; Molarity = [tex]\dfrac{moles}{volume}[/tex]
Molarity = [tex]\dfrac{0.00786 \ mol}{0.04379 \ L}[/tex]
Molarity = 0.17949 mol/L
= 0.1795 M
After the initial neutralization, the molarity at the equivalence point will be:
"0.17949 mol/L"
Concentration of solutionAccording to the question,
→ HF (aq) + KOH (aq) [tex]\rightarrow[/tex] KF (aq) + H₂O
Since, moles of HF = moles of KOH
We know that,
Number of moles = Volume × Molarity
→ 0.020 × 0.393 = 0.02379 × M
By applying cross-multiplication,
The molarity of KOH be:
M = [tex]\frac{0.02\times 0.393}{0.02379}[/tex]
= [tex]\frac{0.00786}{0.02379}[/tex]
= 0.3304 M
By using balanced neutralization reaction,
Volume = 0.020 + 0.02379
= 0.04379 L
hence,
The molarity will be:
= [tex]\frac{Moles}{Volume}[/tex]
By substituting the values,
= [tex]\frac{0.00786}{0.04379}[/tex]
= 0.17949 mol/L
Thus the response above is correct.
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This equation shows the combustion of methanol.
2CH2OH(1) +302(g) → 2C02(g) + 4H2O(g)
How many liters of carbon dioxide gas at STP are produced by the combustion of 64.0 g of methanol
(CH3OH)
A. 44.8L
B. 89.6 L
C. 11.2L. D. 22.4L
Answer: 44.8 L
Explination:
44.8 liters of carbon dioxide gas at STP are produced by the combustion of 64.0 g of methanol. Therefore, option A is correct.
What is combustion ?Combustion is a chemical reaction between two or more substances, usually involving oxygen, that produces heat and light in the form of a flame.
Combustion is a high-temperature exothermic redox chemical reaction that occurs between a fuel and an oxidant, frequently atmospheric oxygen, to produce oxidized, often gaseous products in a mixture known as smoke.
The flash point of methanol is extremely low. This means that even trace amounts of ignition material can start a fire. 44.8 liters of carbon dioxide gas at STP are produced by the combustion of 64.0 g of methanol.
Thus, option A is correct.
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ANSWERIT AND YOU WILL BE MARKED THE BRAINLIEST
Answer:
The answer is definitely D
Explanation:
g An oxidized silicon (111) wafer has an initial field oxide thickness of d0. Wet oxidation at 950 °C is then used to grow a thin film gate of 500 nm in 50 minutes. What is the original field oxide thickness d0 (in nm)?
Answer:
Explanation:
From the information given:
oxidation of oxidized solution takes place at 950° C
For wet oxidation:
The linear and parabolic coefficient can be computed as:
[tex]\dfrac{B}{B/A} = D_o \ exp \Big [\dfrac{-\varepsilon a}{k_BT} \Big][/tex]
Using [tex]D_o[/tex] and [tex]E_a[/tex] values obtained from the graph:
Thus;
[tex]\dfrac{B}{A} = 1.63 \times 10^8 exp \Big [ \dfrac{-2.05}{8.617 \times 10^{_-5}\times 1173}\Big] \\ \\ = 0.2535 \ \ \mu m/hr[/tex]
[tex]B= 386 \ exp \Big [-\dfrac{0.78}{8.617 \times 10^{-3} \times 1173} \Big] \\ \\ = 0.1719 \ \mu m^2/hr[/tex]
So, the initial time required to grow oxidation is expressed as:
[tex]t_{ox} = \dfrac{x}{B/A}+ \dfrac{x^2}{B} - t_o (initial)[/tex]
[tex]where; \\ \\ t_{ox} = 2 \ hrs;\\ \\ x = 0.5 \\ \\ B/A = 0.2535 \\ \\ B = 0.1719[/tex]
∴
[tex]2= \dfrac{0.5}{0.2535}+ \dfrac{0.5^2}{0.1719} - t_o (initial)[/tex]
[tex]2 = 3.4267 - t_o (initial) \\ \\ t_o(initial) = 3.4267 - 2 \\ \\ t_o(initial) = 1.4267 \ hr[/tex]
NOW;
[tex]1.4267 = \dfrac{d_o}{0.2535} + \dfrac{d_o^2}{0.1719} \\ \\ 1.4267 = 3.9448 \ d_o + 5.8173 \ d_o^2 \\ \\ d_o^2 + 0.6781 \ d_o = 0.2453[/tex]
[tex]d_o = \dfrac{-b \pm \sqrt{b^2-4ac}}{2a}[/tex]
[tex]d_o = \dfrac{-(0.6781) \pm \sqrt{(0.6781)^2-4(1)(-0.245)}}{2(10)}[/tex]
[tex]d_o = \dfrac{-(0.6781) \pm \sqrt{0.45981961+0.98}}{20}[/tex]
[tex]d_o = \dfrac{-(0.6781) \pm \sqrt{1.43981961}}{20}[/tex]
[tex]d_o = \dfrac{-(0.6781) + \sqrt{1.43981961}}{20} \ OR \ \dfrac{-(0.6781) - \sqrt{1.43981961}}{20}[/tex]
[tex]d_o =0.02609 \ OR \ -0.0939[/tex]
Thus; since we will consider the positive sign, the initial thickness [tex]d_o[/tex] is ;
≅ 0.261 μm
Show your reasoning in describing what would be the effect on the calculated equilibrium constant for each of the following mistakes.
1. Your buret was not rinsed with NaNCS solution before use and still contained traces of distilled water.
2. The spectrophotometer was set well-past infinite absorbance upon calibration with the sample holder empty.
Answer:
The readings of equilibrium constant is incorrect.
Explanation:
There is a mistake in the value of equilibrium constant if the burette contains traces of distilled water because the water will be present in the solution from which equilibrium constant is calculated. The spectrophotometer did not give the correct reading because its calibration is incorrect. If we want to gain correct readings from the spectrophotometer, we must have to calibrate the instrument correctly.
Incorrect value of equilibrium constant is obtained.
What is equilibrium constant?Equilibrium constant of any reaction tells about the relative ration of the concentration of products to the reactants.
Value of equilibrium constant can be calculated in the aqueous medium where concentration of water also present. If we don't rinse the burette with the reaction solution then the already present traces of water affect the concentration of water during the calculation of equilibrium constant.
As the absorbance of any solution is also directly proportional to the concentration, so if the spectrometer is not calibrated accurately then incorrect value of absorbance also affects the value of equilibrium constant.
Hence, we get incorrect value of equilibrium constant for each of the given mistakes.
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if a compound formula mass was experimentally determined to be 58, the chemical formula could be?
Answer:
NaCl
Explanation:
If you follow traditional rounding, Na atomic mass is 23 and Cl atomic mass 35, 23 +35 = 58.
I was taught that Cl is one of the elements you round to 35.5, but this works if you’re not in an advanced chem class.
2)Explain: How can the shapes of a boat and an airplane help them move faster?
Answer:
Their sleek shape makes them more aerodynamic which reduces the contact force.
Answer: The are formed in a way so they create less friction against the air and water. Helping the jet stream create less traction so it moves faster. Like how a bullet is designed. The pointed front and narrow body helps it move faster through the air. Less things sticking of these object so friction is avoided, and they can easily move speedily. The same thing goes for cars, the more narrow they are as well as pointed makes it easier to push through the air making the wind resistance extremely low.
Hope this helps :)
l need introduction about vitamin please
Answer:
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C
What is the concentration of a 500 mL solution with 25 mol of HF? Write your answer with TWO decimal places and round accordingly.
Answer:
oop I'm thinking hmmmmm
Uranium, an important component of both nuclear weapons and nuclearreactors, has two major isotopes, U-238, which has a half-life of approximately billion years, and U-235, which has a half-life of approximately million years. Both were present in equal amounts at the time of thecreation of the Earth, billion years ago. How many years after the creationof the Earth had the amount of radiation from uranium decayed to half theamount present at the time of the creation of the Earth
Answer:
Hello your question is poorly written below is the well written question
Uranium, an important component of both nuclear weapons and nuclear reactors, has two major isotopes, U-238, which has a half-life of approximately 4.5 billion years, and U-235, which has a half-life of approximately 700 million years. Both were present in equal amounts at the time of the creation of the Earth, 4.5 billion years ago. How many years after the creation of the Earth had the amount of radiation from uranium decayed to half the amount present at the time of the creation of the Earth
Answer : 140 billion years
Explanation:
Given that :
U-238 h1/2 = 4.5 billion years
U-235 h1/2 = 700 million years
At the beginning both Isotopes where present in equal amount
Determine the T years before the amount of Uranium decays to Half
T = ? N'2 = N1 / 2
we know that N = No ( 1/2 )^h where h = time / half-life time
attached below is the detailed solution of the given problem
What is the mass of 4.50mol Ca
The ratio of the measured molar volume of a real gas to the measured molar volume if the gas
were to behave ideally is known as
Answer: compressibility
Explanation:
The ratio of the measured molar volume of a real gas to the measured molar volume of an ideal gas is known as compressibility.
Compressibility is defined by the symbol Z and is calculated by the formula :
[tex]Z=\frac{PV}{nRT}[/tex]
For a gas with ideal behavior, molar volume of an ideal gas is equal to the molar volume of a real gas so Z= 1.
Calculate the Rf value of compounds X and Y based on information (X travels 0.5.0 cm, Y travels 1.0 cm from the origin line; the solvent front is 3.0 cm). Comment on the polarity and separation of X and Y on the TLC plate.
Answer:
Retention factor or [tex]R_f[/tex] value is defined as the ratio of distance traveled by the unknown to the distance traveled by the solvent front.
[tex]R_f=\frac{\text{ distance by unknown}}{\text {distance by solvent}}[/tex]
Putting in the values we get:
[tex]R_f_{X}=\frac{0.50cm}{3.0cm}=0.16[/tex]
[tex]R_f_{Y}=\frac{1.0cm}{3.0cm}=0.33[/tex]
As the [tex]R_f[/tex] value of Y is more than X , it follows that Y compound will be retained less strongly than the compound X. Thus Y is more polar than X.
Ethanol in the body is oxidized to acetaldehyde by liver alcohol dehydrogenase (LADH). Other alcohols are also oxidized by LADH. For example, methanol, which is mildly intoxicating, is oxidized by LADH to the quite toxic product of formaldehyde. The toxic effects of ingesting methanol (a component of many commercial solvents) can be reduced by administering ethanol. The ethanol acts as a competitive inhibitor of methanol by displacing it from LADH. This provides sufficient time for the methanol to be harmlessly excreted by the kidneys. If an individual has ingested 30 mL of methanol (a lethal dose), how much 100 proof whiskey (50% ethanol by volume) must be imbibed to reduce the activity of her LADH towards methanol to 5% of its original value? The adult human body contains ~40L of aqueous fluids throughout which ingested alcohols are rapidly and uniformly mixed. The densities of ethanol and methanol are both 0.79 g/cm3. Assume the KM values of LADH for ethanol and methanol to be 10-3 M and 10-2 M, respectively, and that Ki = KM for ethanol
Answer: The changes are the mL of methanol ingestion (30mL) and the proof of the whiskey (40% ethanol; 80 proof), and the percentage of reduction (1%). I applied the formulas from the last post in reference to this question but am completely lost. The formulas used last time were: 2. Formulas Applied alpha=1 + ([etOH]/KetOH) (V[meOH]/V[etOH])= (Vmax*[meOH]/KmeOH+[meOH])/(Vmax*[meOH]/alpha*KmeOH+[meOH]) which reduces to (V[meOH]/V[etOH])=(alpha*KmeOH+[meOH])/(KmeOH+[meOH]) 3. My attempt Molarity of methanol: 30mL; which equates to 23.7g of methanol; in 40L that is equal to 0.5925 g/L Dividing the molecular weight by 32.04g/mol I get 0.0184925 which is approximately 0.02M; Km is 0.01M Since the molar mass of methanol and ethanol are two fold, I can multiply the g/l by 4. However, unlike the previous problem, I cannot multiply by 2 because I do not have 50% EtOH, so because 40 is less than 50 I assume to multiply by 2.5 yielding: (30mL)(4)(2.5)=300mL 300mL of EtOH to effectively reduce the Methanol to 1%.
HELP FAST 100 PTSCalculate the amount of heat needed to convert 100.0 g of liquid water at 25 °C to water at 100 °C.
Answer:
31,380 Joules
Explanation:
Given Data:
Mass = m = 100 g
Temperature 1 = = 25 °C
Temperature 2 = = 100 °C
Specific Heat Constant = c = 4.184
Change in Temp. = ΔT = 100 - 25 = 75 °C
Required:
Heat = Q = ?
Formula:
Q = mcΔT
Solution:
Q = (100)(4.184)(75)
Q = 31, 380 Joules
Hope this helped!
~AH1807
Answer:
[tex]\Large \boxed{\sf 31400\ J}[/tex]
Explanation:
Use formula
[tex]\displaystyle \sf Heat \ (J)=mass \ (g) \times specific \ heat \ capacity \ (Jg^{-1}\°C^{-1}) \times change \ in \ temperature \ (\°C)[/tex]
Specific heat capacity of water is 4.18 J/(g °C)
Substitute the values in formula and evaluate
[tex]\displaystyle \sf Heat \ (J)=100.0 \ g \times 4.18 \ Jg^{-1}\°C^{-1} \times (100\°C-25\°C)[/tex]
[tex]\displaystyle Q=100.0 \times 4.18 \times (100-25 )=31350[/tex]
A solution has a [OH-] of 1.43x10-9. What is the pH of this solution?
a. 5.2
b. 8.8
C. 9.1
d. 4.9
Answer:
a. 5.2
Explanation:
pOH = -log(1.43 x 10^-9) = 8.845
pH = 14 - pOH = 14 - 8.845 = 5.155 ≈ 5.2
how proved that carbon is present in sugar?
In all living organisms, in substances like carbohydrate, starch, urea etc. To prove sugar contains carbon, take a little amount of sugar in spoon and heat it gently till it melts and turned into yellowish color. On further heating it changes into brown colored mass and then black, which is charcoal.
Answer: sugar treated with strong sulphur acid turns to black
Explanation: sulphur acid removes water from sugars and carbon is left in residue.
This should not to try at home. Water boils when high temperature is achieved.
Also smell of burned sugar occurs
How can you determine if elements have the same properties?
Answer:
You will know if elements have the same properties if they are in the same column (up and down) on the periodic table.
Explanation:
Ex: Lithium and a hydrogren has the same properites bcause they are both on the same line/column. Columns are up and down the table and rows are left and right. Hope this helps
How many moles of carbon dioxide are produced using 5.8 grams of C2H2?
Answer:
50.0 moles CO2
Explanation:
Simone is helping her mom cook. She takes a glass casserole dish directly from the refrigerator and put it in the oven. Which best explains the result of putting the cold dish in the hot oven?
Group of answer choices
The dish stays cool and will not warm.
The dish quickly changes color.
The dish cracks or breaks.
The dish contracts and shrinks.
Answer:
I think the dish contracts and shrinks
Answer:
The dish cracks or breaks.
Explanation:
When glass changes temperature rapidly, it may undergo thermal shock. This is stress that is produced by a sudden change in temperature.
A mixture of nitrogen and xenon gases contains nitrogen at a partial pressure of 251 mm Hg and xenon at a partial pressure of 472 mm Hg. What is the mole fraction of each gas in the mixture?
I uploaded the answer to a file hosting. Here's link:
tinyurl.com/wpazsebu
I need help fast pls someone
Answer:
I would say A. I'm no expert, but it can't be C obviously, and I think wind would hit all of it, wearing off the top as well like the great pyramids. B would be my next choice, but A i think would be best.
The formula for ammonia is NH3. How many moles are in 0.75 g of ammonia?
The number of moles that are present in 0.75 g of ammonia is 0.04 moles.
What is the relation between mass & moles?Relation between the mass and moles of any substance will be represented as:
n = W/M, where
W = given mass = 0.75gM = molar mass = 17g/molOn putting all these values, we can calculate the moles of ammonia as:
n = 0.75g / 17g/mol = 0.04 mole
Hence required moles of ammonia is 0.04 moles.
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If energy cannot be created or destroyed, what happens to the kinetic and potential energy?
Answer:
According to the law of conservation of energy, energy cannot be created or destroyed, although it can be changed from one form to another. KE + PE = constant. ... As the car coasts down the hill, it moves faster and so it's kinetic energy increases and it's potential energy decreases. hope this helps
Explanation:
Answer:
They cannot be destroyed or created however,
Explanation:
it can only be transformed or transferred from one form to another.
Describe two functions of blood.
Answer:
Transports Dissolved gases and Controls pH The pH of blood must remain in the range 6.8 to 7.4, otherwise it begins to damage cells.
Explanation:
main functions tho Transportation. Nutrients from the foods you eat are absorbed in the digestive tract. ...
Defense. Many types of WBCs protect the body from external threats, such as disease-causing bacteria that have entered the bloodstream in a wound.
Maintenance of Homeostasis. Recall that body temperature is regulated via a negative-feedback loop.
This timeline woulchre useful to someone who was writing a report titled
TRUST PLZ HELP MATCH THE BOXES
Answer:
Transform = the third one
convergent = the first one
divergent = the second one
Explanation:
What substance is oxidized in the following reaction? 4HCl + MnO2 → Cl2 + 2H2O + MnCl2
Answer:
Cl⁻ was oxidized.
Explanation:
4HCl + MnO₂ → Cl₂ + 2H₂O + MnCl₂Oxidation can be defined as the process in which the oxidation number of a substance increases.
On the left side of the equation, Cl has a charge of -1 (in HCl); while on the right side of the equation Cl has a charge of 0 in Cl₂.
Thus, Cl⁻ was oxidized.
Four students are gathering information on elements to determine their identity.
Student 1 counts both neutrons and electrons.
Student 2 counts the number of neutrons.
Student 3 counts the number of valence electrons.
Student 4 counts the number of protons.
Which of the following students will correctly identify the element based on their
data?
Answer:
Student 4
Explanation:
In the structure of the atom of an element, there are protons, electrons and neutrons. The number of protons in the atom of such element determines the atomic number of the element. For example, if Calcium contains 20 protons, the atomic no of Calcium will be 20. Since this is so, it means that the identity of an element on the periodic table can be known using the number of protons/atomic no.
According to this question, four students are gathering information on elements to determine their identity. Based on the explanation above, it takes only the number of protons = atomic no. of the element to identify it. Hence, student 4, who counts the number of protons will correctly identify the element using his/her data.
An element's atomic number refers to - (TEKS 8.5A)
Answer:
An element's atomic number refers to the number of protons found in the nucleus of each atom of the element.
Answer:
ur mom
Explanation:
ur mom lol
what is molecular attraction? Am I right?
Answer:
tendency of molecules with unlike electrical charges to attract each other.
Explanation: