Answer:
2 ×10^-3
Explanation:
pH + pOH = 14
pOH = 14-11.3 = 2.7
[OH-] = 10^-pOH = 10^-2.7 = 2×10^-3 M
0.53g of acetanilide was subjected to kjeldahl determination and the ammonia produced was collected in 50cm3 of 0.50M of h2so4.on dilution 250cm3, the acid was titrated against 25cm3 portion of 0.05M sodium carbonate solution. 13.60 of acid was required for each titration. What is percentage of nitrogen in acetanilide
Answer:
10.57% of N in acetanilide
Explanation:
All nitrogen in the sample is converted in NH₃ in the Kjeldahl determination. The NH₃ reacts with H₂SO₄ as follows:
2NH₃ + H₂SO₄ → 2NH₄⁺ + SO₄²⁻
The acid in excess in titrated with Na₂CO₃ as follows:
Na₂CO₃ + H₂SO₄ → Na₂SO₄ + H₂O + CO₂
To solve this question we must find the moles of sodium carbonate = Moles of H₂SO₄ in excess. The added moles - Moles in excess = Moles of sulfuric acid that reacts:
Moles Na₂CO₃ anf Moles H₂SO₄ in excess:
0.025L * (0.05mol / L) = 1.25x10⁻³ moles Na₂CO₃ / 0.01360L =
0.09191M * 0.250L = 0.0230 moles H₂SO₄ in excess.
Moles H₂SO₄ added:
0.050L * (0.50mol / L) = 0.0250 moles H₂SO₄ added
Moles that react:
0.0250 moles - 0.0230 moles = 0.0020 moles H₂SO₄
Moles of NH₃ = Moles N:
0.0020 moles H₂SO₄ * (2mol NH₃ / 1mol H₂SO₄) = 0.0040 moles NH₃ = Moles N
mass N and mass percent:
0.0040 moles N * (14g / mol) = 0.056gN / 0.53g * 100 =
10.57% of N in acetanilidePLEASE HELP WITH CHEM !! Calculate the [OH-] of each of the following solutions given the [H+]. AND Classify each of the solutions in the question above as either acid, base, or neutral. AND FIND THE PH
pH, pOH, [H+], and [OH-] are all interrelated. For simplicity, we assume that we're working with aqueous solutions at 25 °C.
The following mathematical relations are relevant here:
pH = -log[H⁺]pOH = -log[OH⁻][H⁺] = 10^-pH[OH⁻] = 10^-pOHpH + pOH = 14[H⁺] × [OH⁻] = 10^-14A pH of 7 is neutral; a pH less than 7 is acidic; and a pH greater than 7 is basic.
---
We are given four solutions of varying [H⁺], and we want to find the pH and the [OH⁻]. The pH will tell us whether the solution is neutral, an acid, or a base.
Finding the [OH⁻]Using the relationship [H⁺] × [OH⁻] = 10^-14, we can calculate the [OH⁻] of each solution by dividing 10^-14 by the given [H⁺]:
[OH⁻] = 10^-14/(3.3 × 10^-5) = 3.0 × 10^-10
[OH⁻] = 10^-14/(4.0 × 10^-8) = 2.5 × 10^-7
[OH⁻] = 10^-14/(7.2 × 10^-11) = 1.4 × 10^-4
[OH⁻] = 10^-14/(8.2 × 10^-4) = 1.2 × 10^-11
Note: While not indicated here, the units for [H⁺] and [OH⁻] are moles/liter (M).
Finding the pHTo find the pH of each solution, we take the negative logarithm of the [H⁺] with base 10, i.e., pH = -log₁₀[H⁺]:
pH = -log(3.3 × 10^-5) = 4.48
pH = -log(4.0 × 10^-8) = 7.40
pH = -log(7.2 × 10^-11) = 10.14
pH = -log(8.2 × 10^-4) = 3.09
Note that, for significant figures involving logarithms, the number of decimal places should equal the number of significant figures in the argument of our logarithm (the argument is what we're taking the -log of). Since we're taking the -log of quantities given to two significant figures, our corresponding pH values are given to two decimal places.
Acid, Base, or Neutral?As mentioned above, a pH = 7 is neutral, a pH < 7 is acidic, and a pH > 7 is basic.
4.48 < 7, so the first solution is an acid.
7.40 > 7, so the second solution is a base.
10.14 > 7, so the third solution is a base.
3.09 < 7, so the fourth solution is an acid.
3 points
5. Which of the following is true regarding the atoms involved in a
chemical reaction? *
a) During a chemical reaction, atoms will always be combined into much larger
molecules.
b) Some of the atoms will always be changed into a different type of atom by a
chemical reaction.
c) Some of the atoms present before the reaction will always be lost during a
chemical reaction.
d) The same number of each type of atom will always be present before and after a
chemical reaction takes place.
1. When _____
are added or removed from an atom, _____
is formed
Answer:
1.) protons or electrons 2.) ion
Explanation:
give an example of how an organism can use surface tension?
Answer:Insects, such as water striders, and spiders, such as fisher spiders, can glide or scamper across the surface of water. These critters are small enough that their weight can be supported almost entirely by surface tension, the relatively weak forces that hold water molecules together.
Explanation:
Answer:
Examples of surface tension Water striders are able to walk on top of water due to a combination of several factors. Water striders use the high surface tension of water and long, hydrophobic legs to help them stay above water. Water striders use this surface tension to their advantage through their highly adapted legs and distributed weight.
Explanation:
pls mark brainliest
During the chemical reaction given below 21.71 grams of each reagent were allowed to react. Determine how many grams of the excess reagent are left over after the reaction is complete. 2SO2()+O2()⟶2SO3()
Answer: 16.32 g of [tex]O_2[/tex] as excess reagent are left.
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} SO_2=\frac{21.71g}{64g/mol}=0.34mol[/tex]
[tex]\text{Moles of} O_2=\frac{21.71g}{32g/mol}=0.68mol[/tex]
[tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]
According to stoichiometry :
2 moles of [tex]SO_2[/tex] require = 1 mole of [tex]O_2[/tex]
Thus 0.34 moles of [tex]SO_2[/tex] will require=[tex]\frac{1}{2}\times 0.34=0.17moles[/tex] of [tex]O_2[/tex]
Thus [tex]SO_2[/tex] is the limiting reagent as it limits the formation of product and [tex]O_2[/tex] is the excess reagent.
Moles of [tex]O_2[/tex] left = (0.68-0.17) mol = 0.51 mol
Mass of [tex]O_2=moles\times {\text {Molar mass}}=0.51moles\times 32g/mol=16.32g[/tex]
Thus 16.32 g of [tex]O_2[/tex] as excess reagent are left.
Ammonia (NH3) is widely used as a fertilizer and in many household cleaners. How much ammonia is produced when 5.81 mol of hydrogen gas react with an excess of nitrogen gas?
Answer:
65.841 g
Explanation:
The balanced equation for this reaction is;
N2 + 3H2 → 2NH3
From the question, we are interested in ammonia and the hydrogen gas.
From the equation
3 mol of H2 produces 2 mol of NH3
5.81 mol would produce x
Solving of x;
x = 5.81 * 2 / 3
x = 3.873 mol
Converting to mass;
Mass = Number of moles * molar mass
Mass = 3.873 * 17 = 65.841 g
Which is an example of a chemical change?
A. heating a block of ice to form liquid water
B. heating a tungsten wire until it glows brightly
C. adding sugar crystals to water to form a clear, colorless liquid
D. passing an electric current through water to form hydrogen and oxygen
Answer:
D. passing an electric current through water to form hydrogen and oxygen
Explanation:
only one that's not just a physical change.
Determine from the balanced chemical reaction if
the derived mole ratio is correct or incorrect.
2FeBr3 + 3Na2S → Fe2S3 + 6NaBr
2 moles FeBra
3 moles Na2S
Answer:
Correct
Explanation:
According to the balanced chemical reaction, 2 mol FeBr3 are consumed for every 3 mol Na2S consumed.
A balanced equation obey the law of conservation of mass. The coefficients are the numbers which are added to balance the chemical equation. Here the given mole ratio is correct.
What is a balanced equation?An equation in which the number of atoms of reactants and products on both sides of the equation are balanced is defined as the balanced chemical equation. The coefficients which are added in front of the formula of each component represents the number of the species.
A molar ratio denotes the ratio between the amounts in moles of any two compounds involved in a balanced chemical reaction. By comparing the coefficient of each component, the mole ratio can be determined.
Here for the given reaction, for every 3 moles of Na₂S consumption 2 moles of FeBr₃ is also consumed. So the molar ratio of Na₂S to FeBr₃ is 2/3. Molar ratios are used as the conversion factors between products and reactants in many chemistry problems.
To know more about mole ratio, visit;
https://brainly.com/question/29095152
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object with a mass of 30 kg is observed to accelerate at the rate of 4 m/s2. Calculate the force required
NH₄⁺(aq)+NO₃⁻(aq) → NH₄NO₃(s)
How much energy is released when 3 moles of NH₄+ react?
1) -25.69 kJ
2) -51.38 kJ
3) -77.07 kJ
4) -102.76 kJ
(science)Which type of harmful alleles may disappear from a population more slowly when the individual may still reproduce?
a.a dominant allele
b.a recensive allele
c.a double allele
d.a single allele
Can someone please help me with the right answer? I only have one more attempt :(
what is the mass number for an atom that has 36 protons 36 electrons and 40 neutrons
Answer:
76
Explanation:
Mass number = number of protons plus the number of neutrons
So, 36 + 40 = 76
What is defined as the plants and animals and the physical surroundings, including the sun, air, soil, and water?
Answer:
Ecosystem
Explanation:
The answer is ecosystem because the ecosystem includes the community such as living things and the enviornment of nonliving things such as the sun!
Answer:
ecosystem I'm pretty sure
What is a mole of something? Why do scientists use the concept of a mole?
Answer: A mole is a chemical unit to measure mass of substance.
Explanation:
A mole can be defined as 6.02214076 × 1023 of atoms, ions, molecules and others. A mole is the total amount of discrete entity within a substance present in the form of atoms, ions, and molecules. As atoms, ions, molecules are small entities within any substance so it is necessary to measure each of them and recognize them so the scientists development the concept of mole. It is the convenient unit of measurement because of the presence of greater number of molecules, atoms, and ions present in any substance.
Answer:
The mole is an SI unit used to measure the amount of any substance. One mole is exactly 6.02214076×10 23 particles.
Explanation:
The concept of the mole is important for scientists because it means that one mole of any element has exactly the same number of atoms as one mole of any other element. This information allows chemists to count atomic particles for even very complex chemistry formulas and reactions.
Eight ounces (1 fl. Oz = 29.57 ml) of orange juice contains 160% of the recommended daily allowance of vitamin c (rda = 75-90 mg for adults). How many milliliters of the orange juice will provide 100% of the recommended daily allowance?
What element is found in water?
1. Carbohydrate
2. Carbon
3. oxygen
Explanation:
3. the element is oxygen
Which body system includes the lungs?m
Answer: The respiratory system
Explanation: It includes the nose, mouth, throat, voice box, windpipe, and lungs. Air enters the respiratory system through the nose or the mouth.
the process plants use to make sugar for food
A respiration
B eqidermis tissue
C photosynothedis
D chlorophyll
in pressure dunt
uwing
frost shattering
Answer:
i dont get it???????
Explanation:
science:my chosen place is bonifacio global city
i choose this place because?
Answer:
Rewrite the following sentence in reported speech
The chair person said,"A hearty welcome to all present!"
a weather balloon expands from 3.00 L to 3.25 L. The atmospheric pressure is 0.96 atm. How much work was done on the surroundings?
I really, really, really need help with this. I've been struggling so much to understand thermochemistry!
Answer:
0.96
Explanation:
is copper an elementary substance or a compound?
Which diagram represents matter with a definite volume but no
definite shape?
i think it is Substance C
At higher altitudes would there be more or less
oxygen available to breathe?
a. Less oxygen is available at higher altitudes.
b. More oxygen is available at higher altitudes.
Answer: less oxygen available at higher altitudes
Explanation:
The higher in elevation you get, the lower the air pressure, allowing oxygen atoms to spread out farther, therefore making available oxygen less.
Sulfuric acid reacts with aluminum hydroxide by double replacement producing aluminum sulfate and water Write chemical reaction. If 30 g of sulfuric acid reacts with 25 g of aluminum hydroxide, identify the limiting reactant?
Answer: [tex]H_2SO_4[/tex] is the limiting reagent.
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
The balanced chemical equation is:
[tex]3H_2SO_4(aq)+2Al(OH)_3(aq)\rightarrow Al_2(SO_4)_3(aq)+6H_2O(l)[/tex]
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} H_2SO_4 =\frac{30g}{98g/mol}=0.31moles[/tex]
[tex]\text{Moles of} Al(OH)_3=\frac{25g}{78g/mol}=0.32moles[/tex]
According to stoichiometry :
3 moles of [tex]H_2SO_4[/tex] require = 2 moles of [tex]Al(OH)_3[/tex]
Thus 0.31 moles of [tex]H_2SO_4[/tex] will require=[tex]\frac{2}{3}\times 0.31=0.21moles[/tex] of [tex]Al(OH)_3[/tex]
Thus [tex]H_2SO_4[/tex] is the limiting reagent as it limits the formation of product and [tex]Al(OH)_3[/tex] is the excess reagent.
how many moles of solute are present in a 2 L of a 25M potassium nitrate solution
a. 0.5 moles
b. 2 moles
c. 50 moles
d. 25 moles
I NEED THIS ANSWER ASAP, im taking the quiz right now and i need HELPPP
Answer:
50 moles
Explanation:
took the quiz
Use the drop-down menus to complete the sentences.
The gain of electrons is called _________
The loss of electrons is called _________
Answer:
1.Reduction
2.oxidation
Explanation:
Answer:
Reduction
Oxidation
Explanation:
An ideal gas fills a balloon at a temperature of 227ºC and standard pressure. By what factor will the volume of the balloon change if the gas in the balloon is heated to 327ºC at standard pressure? Identify which gas law applies and show your work to receive full credit. Highlight the correct answer below. (2 points)
a. 227/327
b. 5/6
c. 6/5
d. 2/1
e. 327/227
Answer:
e. 327/227
Explanation:
This is the correct standard pressure.