15) What is the hydronium ion concentration [H3O + ] of a 0.125 M hydrocyanic acid solution with Ka = 4.9 × 10-10? The equation for the dissociation of hydrocyanic acid is: HCN(aq) + H2O(l) ⇌ H3O+(aq) + CN- (aq)
The hydronium ion concentration [H₃O⁺]=7.826 x 10⁻⁶
Further explanationIn general, the weak acid ionization reaction
HA (aq) ---> H⁺ (aq) + A⁻ (aq)
Ka's value
[tex]\large {\boxed {\bold {Ka \: = \: \frac {[H ^ +] [A ^ -]} {[HA]}}}}[/tex]
Reaction
HCN(aq) + H₂O(l) ⇌ H₃O⁺(aq) + CN⁻ (aq)
0.125
x x x
0.125-x x x
[tex]\tt Ka=\dfrac{[H_3O^+][CN^-]}{[HCN^-]}[/tex]
[tex]\tt 4.9\times 10^{-10}=\dfrac{x^2}{0.125-x}\approx \dfrac{x^2}{0.125}\\\\x^2=6.125\times 10^{-11}\\\\x=7.826\times 10^{-6}[/tex]
What is the weight of 12.0 moles of water?
Answer:
216g H2O
Explanation:
H = 1
O = 16
H= 2 × 1 = 2
O= 1 × 16 = 16
16 + 2= 18g/mol
18g H2O = 1 mol
X g H2O = 12 mol
X × 1 = 18 × 12
X = 216 g/mol
The weight of 12.0 moles of water is determined as 216 g.
What is the weight of the water?The weight of water is determined from the molecular weight of water. The molecular weight of water is given 18 g/mol.
The weight of 12 moles of water is calculated as follows;.
W = nM
W = 12mole x 18 g/mol
W = 216 g
Thus, the weight of 12.0 moles of water is determined as 216 g.
Learn more about weight here: https://brainly.com/question/2337612
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Ai +O2 =Ai2O3 how many atoms of oxygen exist in this product
In which direction does heat energy move? (2 points)
a
From cold objects to colder objects
b
From colder objects to warmer ones
c
From warmer objects to colder ones
d
From warm objects to warmer objects
Answer: C.
Explanation:
This is called entropy I believe. (it wouldn't let me answer before)
Convert 840 mL to liters ( be sure to keep the appropriate number of significant figures - also, only enter a number DO NOT INCLUDE UNITS)
Calculate the molarity of a solution prepared by dissolving 0.20 mol of KNO3 into enough water to make 250 mL of solution. ______ M
Answer:
0.8M
Explanation:
Given parameters:
Number of moles of KNO₃ = 0.2mol
Volume of KNO₃ = 250mL
Unknown:
Molarity of the solution = ?
Solution:
The molarity of a solution is the number of moles in a given volume of a solution;
Molarity = [tex]\frac{number of moles }{volume}[/tex]
We need to convert the given volume to L;
1000mL = 1L
250mL will give 250 x 10⁻³L = 0.25L
So;
Molarity = [tex]\frac{0.2}{0.25}[/tex] = 0.8M
Answer:
0.8 M
Explanation:
The formula is mol divided by liters. Converting 250 ml to .25 liters is important. Dividing .2 by .25 gets the answer. (I swear it’s right but it’s graded wrong so take this with a grain of salt)
the difference between a molecule and a compound is that a compound is made up of atom from
Answer:
answer explained below.
Explanation:
hey! a molecule is made up of two or more atoms, and a compound is made up of two or more elements. not all molecules are compounds, but all compounds are molecules, because compounds are made up of different atoms.
example: O2 is a molecule but not a compound because it is made up of the same element, but has more than one atom.
At STP, a 50-gram sample of H20(I) and a 100-gram sample of H20(I) have
Answer:
(1) the same chemical properties .
Explanation:
Hello!
In this case, among the options:
(1) the same chemical properties
(2) the same volume
(3) different temperatures
(4) different empirical formulas
We can see that they have the same chemical properties as they at the same conditions, same type of bond (polar), molecular geometry, bond angle (104.5 °) and so on. Nevertheless, at STP (1 atm and 273.15 K) they do not have the same volume since the larger the mass, the larger the volume, they have the same temperature and the both of them are H₂O.
It means that the answer is (1) the same chemical properties .
Best regards.
Determine a piece of copper with a volume of 100 cm power 3 has a mass of 890 g. Explain how you could use this information to find out how much mass would be in 13 cm power 3 of copper
Calculate the number of moles in 11.0 grams of NaOH . Please show your work to receive credit.
Answer: 0.275 moles
Explanation: Na- 22.99g (on periodic table)
O- 16g and H- 1.01
22.99 + 16 + 1.01 = 40g/mol of NaOH
11g of NaOH / 40g / mol of NaOH = 0.275mol NaOH
The table shows the average number of pounds of trash generated per person per day in the United States from 1970 to 2010. Use the statistics calculator to calculate the mean and median. Round the answers to the nearest hundredth.
Median =
Mean =
Answer: median :4.44 mean :4.11
Explanation:
i did test on Edge
Which feature is used to classify a rock based on its composition?
the origin of the rock
the texture of the rock
the types of minerals in the rock
the shapes of the crystals in the rock
Answer:
the types of minerals in the rock
Answer:
C
Explanation: I took the test and got it right (first person is right)
Someone help me plz I’ll give u BRAINLIEST!! I’ll really appreciate for ur help I suck at writing essay’s PLZ PLZ!!!!
Answer:
i cant see what it says
Explanation:
OUTLINE
Paragraph 1: Introduction
Paragraph 2: Body Paragraph
Paragraph 3: Body Paragraph
Paragraph 4: Body Paragraph
Paragraph 5: Conclusion
Think of the introduction and conclusion as “bookends” that serve to hold the essay tightly together. The
introduction will “push” into or initiate the examination of your topic and the angle you decide to focus on, while
the conclusion will “pull” tight all the ideas that you have gathered together for a unified essay.
Remember, the five-paragraph model can be expanded to include more body paragraphs that probe more deeply
into your subject. Check with your instructor to ensure whether or not you can exceed this length for an
assignment.
The introductory paragraph should include the following elements:
Background information: Enough information necessary for your reader to understand your topic
Thesis statement: Indicates your paper’s topic, makes your paper’s purpose clear, and provides an
overview of the three main supporting points that will unify the essay. The thesis statement is typically
the last sentence.
If you are writing in response to a text, the introduction should include the title, author, and genre of that
piece.
Begins with a topic sentence that identifies one main idea that will be discussed as support or proof for the
thesis statement
Supporting sentences use specific details, demonstrated through closely related examples or evidence, to
expand and explain the main idea. Generally, a well-developed paragraph has at least five to eight
sentences.
Paragraph unity means that all ideas in a paragraph are closely related to its topic sentence and further
develop that topic sentence. That is, all sentences in a single paragraph must be unified around a central
point or idea.
This paragraph, and any subsequent body paragraph, should begin with a topic sentence that signals the
reader that a new idea or point is being introduced.
As you organize your essay, keep in mind its coherence. Coherence refers to connections among
paragraphs and ideas—the logical sequence of your thoughts.
o Use transition words or phrases at the outset of your body paragraphs and to move from one idea
to another within your paragraphs.
o Have you transitioned logically from the main idea in the previous paragraph to this one? Are you
making clear connections among the paragraphs and ideas? Be sure to think about coherence during
the revision stage of the writing process.
This paragraph begins with the final topic sentence that relates back to the remaining point mentioned in the
thesis statement. Each paragraph should contain a new main idea.
Again, flesh out this main idea with specific examples, details, and relevant support.
Be sure to maintain paragraph unity. That is, each sentence must relate to your topic sentence.
The conclusion revisits your overall purpose for writing and often invites your reader to consider the
implications of why your ideas are significant.
The conclusion may restate the thesis, summarize the paper’s major points, or leave the reader with a final
thought to ponder. Several other methods for writing conclusions are included on a separate Tutoring Center
handout. If you choose to restate the thesis or summarize the essay’s main ideas, do not repeat the same
wording from the introduction or body paragraphs. Remember not to introduce new, unrelated ideas in the
conclusion
5. What could you do to convert from meters to centimeters? *
A. There is no standard way to convert these units.
B. Leave the decimal in the same position.
C. Move the decimal to the right.
D. Move the decimal to the left.
C.
centi- is essentially 10^2 of one meter.
If you had 100m, multiplying 100 by 10^2 (or 100) would give you 10000 cm.
which physical change is endothermic
Answer:The physical changes that are endothermic are melting, vaporization and sublimation.
Explanation:
Translate each number into standard notation
4.52 x 10 power3
Answer:
4.52×1000=4520
Explanation:
4.52*1000=4520
A sample of gas is placed into an enclosed cylinder and fitted with a movable piston. Calculate the work (in joules) done on the gas if it is compressed from 13.43 L to 6.87 L with a pressure of 1.91 atm.
Answer:
Work done = 664.69 J
Explanation:
Given data:
Work done = ?
Initial volume = 13.43 L
Final volume = 6.87 L
Pressure = 1.91 atm
Solution:
work done = W = -PΔV
ΔV = V₂- V₁
work done = w = -P(V₂- V₁)
Now we will put the values in formula.
W = - 1 atm (6.87 L - 13.43 L)
W = - 1 atm (-6.56 L)
W = 6.56 atm.L
atm.L to joule:
6.56 atm.L × 101.325 J / 1L.atm
664.69 J
What causes the emission of light?
Answer:
When the electrons in the atom are excited, for example by being heated, the additional energy pushes the electrons to higher energy orbitals. When the electrons fall back down and leave the excited state, energy is re-emitted in the form of a photon. The wavelength (or equivalently, frequency) of the photon is determined by the difference in energy between the two states. These emitted photons form the element's spectrum.
The fact that only certain colors appear in an element's atomic emission spectrum means that only certain frequencies of light are emitted. Each of these frequencies are related to energy by the formula:
{\displaystyle E_{\text{photon}}=h\nu }E_{\text{photon}}=h\nu ,
where {\displaystyle E_{\text{photon}}}E_{\text{photon}} is the energy of the photon, {\displaystyle \nu }\nu is its frequency, and {\displaystyle h}h is Planck's constant. This concludes that only photons with specific energies are emitted by the atom. The principle of the atomic emission spectrum explains the varied colors in neon signs, as well as chemical flame test results (described below).
The frequencies of light that an atom can emit are dependent on states the electrons can be in. When excited, an electron moves to a higher energy level or orbital. When the electron falls back to its ground level the light is emitted.
Explanation:
What’s the difference between Fe and Fe2+?
Fe is the pure element (Iron) while Fe2+ is an isotope of Fe.
Stomach acid is predominately hydrochloric acid. Write the balanced chemical equation for the neutralization reaction between HCI and the active ingredient.
Express your answer as a chemical equation. Identify all of the phases in your answer
Answer:
HCl + Mg(OH2) ---> MgCl2 + H2O
Explanation:
hydrochloric acid + magnesium hydroxides ==> magnesium Chloride (a salt) + Water
HCl + Mg(OH2) ---> MgCl2 + H2O
the sun has the same diameter as jupiter?
A Geiger counter used in several applications over the course of a typical day produces on the average 100 counts per second. The tube is in the form of a cylinder 5 cm in diameter by 20 cm long and is filled with a mixture of 90% argon and 10% ethanol to a pressure of 0.1 atmosphere. In the Geiger-Muller region, each output count results from the formation of about 1010 ion-electron pairs. How long will it take for one-third of the quenching gas to be used up, thus necessitating replacement of the tube
Answer:
As it is given that
[tex]activity=\lambda= 100\\[/tex]
[tex]Number~of ~counts=100/second\\[/tex]
Using formula
[tex]ln(\frac{N}{N_o})=-\lambda\cdot t\\\\[/tex]
or
[tex]-\frac{ln(\frac{N}{N_o})}{\lambda}= t\\\\[/tex]
where [tex]N=\frac{N_o}{3}[/tex]
[tex]-\frac{ln(\frac{1}{3})}{100}= t\\\\\-\frac{-1.0986}{100}=t\\\\[/tex]
[tex]\frac{1.0986}{100}=t\\1.0986\cdot 10^{-2}seconds=t\\[/tex]
Anions have a _______ charge and cations have a _______ charge
Explanation:
Anions have a negative charge resulting from the gain of one or more electrons to become stable.
Cations have a positive charge due to the loss of two or more electrons in order to become stable or have a noble gas configuration.
Hope this helps you
Wich of the following does not directly affect the weather
Answer:
Tings that effect weather is basically the following:
Distance from seaAltitudeDistance to the equator or poles.MountainsJet streams,etcHow many gases are there that are not noble gases
Answer:
Noble gas, any of the seven chemical elements that make up Group 18 (VIIIa) of the periodic table. The elements are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).
Explanation:
I pretty much covered it in my answer!
Pls Brainliest! It would mean a lot! ;)
Which option(s) correctly shows an anion? Select all that apply.
Answer:
x
Explanation:
becaue neutron equal to mass num -atomic num
Convert 4.30×10^25 molecules of NH3 to moles please do step by step so I can Understand
Explanation:
Number of molecules: 4.30×10²⁵
We need to find out the total number of moles.
Now, as per Avogadro's law, 6.02×10²³ of anything (Avogadro's number) constitutes a unit called one mole. Just like 12 is a dozen, 6.02×10²³ is a mole.
If you were given 24 bananas and you had to find out the number of dozens, you would divide the total number of bananas (24) by the number of bananas in one dozen (12).
We do exactly the same here: divide the total number of molecules (4.30×10²⁵) by the number of molecules in one mole (6.02×10²³) to get the number of moles.
4.30×10²⁵ / 6.02×10²³ = number of moles
Solving, we get number of NH3 moles = 71.4 which is your final answer!
Hope this helps :D
which metal is most likely to form more than one kind of positively charged ion
Answer:
metal atoms lose electrons to form positivity charged ions. non metal atoms gain electrons to form negatively charged ions
50 POINTS! PLEASE HELP!A gas in a balloon at constant pressure has a volume of 120.0mL at -12.30C. What is its volume at 197.00C?
Answer:
Final volume=V₂ = 216.3 mL
Explanation:
Given data:
Initial volume = 120.0 mL
Initial temperature = -12.3 °C (-12.3 +273 = 260.7 K)
Final volume = ?
Final temperature = 197.0 °C (197+273 = 470 K)
Solution:
We will apply Charles Law to solve the problem.
According to this law, The volume of given amount of a gas is directly proportional to its temperature at constant number of moles and pressure.
Mathematical expression:
V₁/T₁ = V₂/T₂
V₁ = Initial volume
T₁ = Initial temperature
V₂ = Final volume
T₂ = Final temperature
Now we will put the values in formula.
V₁/T₁ = V₂/T₂
V₂ = V₁T₂/T₁
V₂ = 120 mL × 470 K /260.7K
V₂ = 56400 mL.K /260.7K
V₂ = 216.3 mL
Other than lowering the cost of producing coins, what could be another added benefit of changing the metals used to make coins?(hint: think of the density...why would a metal that is less dense be beneficial?)
Answer:
See explanation
Explanation:
A coin is money made from metal stuff. Common coinage metals are copper, silver, nickel etc.
One consideration in coin production is the density of the coin. A coin of less density will have lesser mass and occupy a lesser volume. This makes it easier to carry the coin around.
Coins should therefore be made of low density metals so that they can easily be carried about.