Answer:
[H⁺] = 0.000048936M
pH = 4.31
Explanation:
Acetic acid, CH₃COOH, dissociates in water as follows:
CH₃COOH(aq) ⇄ H⁺(aq) + CH₃COO⁻(aq)
And Ka is defined as:
Ka = 1.76x10⁻⁵ = [H⁺] [CH₃COO⁻] / [CH₃COOH]
Where [] are equilibrium concentrations of the species.
The 0.000185M of acetic acid will decreases X, and X of [H⁺] and [CH₃COO⁻] will be produced. That means Ka is:
1.76x10⁻⁵ = [X] [X] / [0.000185 - X]
3.256x10⁻⁹ - 1.76x10⁻⁵X = X²
3.256x10⁻⁹ - 1.76x10⁻⁵X - X² = 0
Solving for X:
X = -0.000066M → False solution. There is no negative concentrations.
X = 0.000048936
As [H⁺] = X,
[H⁺] = 0.000048936M
And pH = -log [H⁺]
pH = 4.31You need to prepare an acetate buffer of pH 5.36 from a 0.900 M acetic acid solution and a 2.62 M KOH solution. If you have 680 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a bufer of pH 5.93? The pKa of acetic acid is 4.76.
Answer:
Explanation:
pH = pKa + log [ CH₃COO⁻ ] / [CH₃COOH ]
5.36 = 4.86 + log [ CH₃COO⁻ ] / [CH₃COOH ]
log [ CH₃COO⁻ ] / [CH₃COOH ] = .5
[ CH₃COO⁻ ] / [CH₃COOH ] = 3.16
moles of CH₃COOH = .680 x .9 = .612 M
Let x mole of KOH is required
x /( .612 - x ) = 3.16
x = 1.933 - 3.16 x
x = .46488
.46488 moles of KOH will be required
volume required be V
v x 2.62 = .46488
v = .1774 L
= 177.4 mL
177.4 mL of 2.62 M KOH will be required .
The number of milliliters of the KOH solution is 177.4 mL
Calculation of the number of milliliters of the KOH solution:Since we know that
H = pKa + log [ CH₃COO⁻ ] / [CH₃COOH ]
5.36 = 4.86 + log [ CH₃COO⁻ ] / [CH₃COOH ]
Now
log [ CH₃COO⁻ ] / [CH₃COOH ] = .5
[ CH₃COO⁻ ] / [CH₃COOH ] = 3.16
Therefore,
moles of CH₃COOH = .680 x .9 = .612 M
here we assume x mole of KOH
So,
x /( .612 - x ) = 3.16
x = 1.933 - 3.16 x
x = .46488
Now the volume required is
v x 2.62 = .46488
v = .1774 L
= 177.4 mL
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What is an atomic change?
DO NOT COPY AND PASTE FROM GOOGLE, THAT DOESN'T HELP.
Explanation:
Atomic change is indivisible change and can NEVER partly succeed it can only fully succeed or Not succeed at all.
Calculate the number of carbon atoms in a 130.0 g sample of camphor (C10H16O). Be sure your answer has a unit symbol if necessary, and round it to 4 significant digits.
Given :
Mass of sample of camphor [tex](C_{10}H_{16}O)[/tex] , m = 130 g .
To Find :
the number of carbon atoms in given sample .
Solution :
Molecular mass of camphor is :
[tex]M=152\ g/mol[/tex] .
Moles of camphor ,
[tex]n=\dfrac{m}{M }\\\\n=\dfrac{130}{152}\\\\n=0.86[/tex]
1 mole of camphor contains 10 moles of carbon .
So , 0.86 moles of camphor contains 8.6 moles of carbon .
1 mole of any substance contains [tex]6.022 \times10^{23}[/tex] numbers of atoms/molecules .
So , number of atoms in 8.6 moles of carbon is :
[tex]N=6.022\times 10^{23}\times 8.6\\\\N=5.179\times 10^{24}[/tex]
Hence , this is the required solution .
6. Match the si base units below with their functions.
second distance-
meter temperature-
kilogram time -
kelvin mass-
liter volume-
To solve this we must be knowing each and every concept related to International System of Units. Therefore, in the below given ways matching can be done.
What is SI unit?A metric system that is utilized as a recognized international measuring standard is known as the International System of Units (SI). The English translation of the French word Systeme International is SI unit.
It is essential for the advancement of technological and scientific research in order to prevent misunderstanding within units. It has 22 derived units defined by 7 basic units.
distance- metre (m)
temperature- Kelvin (K)
time - second(s)
mass- kilogram (Kg)
volume- liter (l)
Therefore, in the above given ways matching can be done.
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Give the electron configurations for the following ions: Al3+, Ba2+, Br- and O2-
Explanation:
Al3+ has 10 electrons. The electronic configuration is;
1s² 2s² 2p⁶
Ba2+ has 54 electrons. The electronic configuration is;
1s² 2s² 2p6 3s² 3p⁶ 3d10 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶
Br- has 37 electrons. The electronic configuration is;
1s² 2s² 2p6 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶
O2- has 10 electrons. The electronic configuration is;
1s² 2s² 2p⁶
A potassium ion (K+) would most likely bond with _____.
Mg+
O
Cl-
Na+
Answer:
Chlorine
Explanation:
Answer:
That would be the negative ion: Cl-.
Temperature is the measure of average potential energy particles of a substance.
TRUE or FALSE
Answer:True
Explanation:
Answer: False
Explanation: Temperature is not the potential energy particles, it is the moving, or kenetic energy cells
The density of pure silver is 10.5 g/cm3 at 20°C. If 5.25 g of pure silver pellets is added to a graduated cylinder containing 16.1 mL of water, to what volume level will the water in the cylinder rise?
Answer:
The correct answer is 16.6 mL
Explanation:
The density of a substance is defined as its mass per unit of volume. Thus:
density = mass/volume
So, to calculate volume: volume = mass/density
Given:
density= 10.5 g/cm³
mass= 5.25 g
We calculate the volume occupied by silver as follows:
volume= mass/density= (5.25 g)/(10.5 g/cm³)= 0.5 cm³
Moreover, we know that 1 cm³= 1 ml. So, a mass of 5.25 g of pure silver occupies a volume of 0.5 ml. If we add the mass of silver to a graduated cylinder with 16.1 mL of water, the final volume will be given by the initial volume of water plus the volume occupied by silver:
volume level = 16.1 mL + 0.5 mL = 16.6 mL
The density of the pure silver substance is defined as the mass per volume. The water level of the cylinder will rise to 16.6 mL after silver pellets are added to the cylinder.
What is density?The density of the silver metal can be explained by the division of the mass of the silver pellets by the volume of the water in the cylinder. The density has been seen in inverse relation to the volume and has been decreasing with an increase in volume.
Similarly, if the volume of the solution is decreased then the density of the substance will increase. As D ∝ 1 /V.
The density of the substance is given as:
Density (D) = mass ÷ volume
Given,
Density (D) = 10.5 g/cm³
Temperature = 20°C
Mass of silver pellets = 5.25 grams
The volume of water in the graduated cylinder = 16.1 mL
The volume of the silver is calculated as:
Volume = mass ÷ density
V = 5.25 g ÷ 10.5 g/cm³
= 0.5 cm³
= 0.5 mL (1 cm³ = 1 mL)
The volume level is calculated by adding the volume of silver and water as: 16.1 mL + 0.5 mL = 16.6 mL
Therefore, 16.6 mL is the volume.
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What is the name of the element that has 20 protons in the its nucleus ? *
Answer:
Calcium.
Explanation:
Calcium has an atomic number in the periodic table equivalent to 20.
Good luck, hope this helped!
A student is given a sample of matter to classify. The sample is uniform in color and texture. Based on this information, the student can determine which of the following?
Based on these data, what can Benito safely conclude about the sample?
Group of answer choices
A.The sample is not a heterogeneous mixture.
B.The sample is not a homogeneous mixture.
C.The sample is not a compound.
D.The sample is not an element.
Answer:
A.The sample is not a heterogeneous mixture.
Explanation:
A homogenous mixture is a mixture that is not chemically bonded, but it is uniform in its composition.
An element is made up of one type of atom. An element is uniform in its composition (i.e. color, texture).
A compound is made up of more than one type of element or atom chemically bonded together. A compound is uniform in its composition (i.e. color, texture).
A heterogeneous mixture is a mixture that is not uniform in composition. i.e. it does not have the same color or texture.
The conclusion that the student can arrive at is that "the sample is not a heterogeneous mixture."
A heterogeneous mixture is composed of more than one substance. Hence, a heterogeneous mixture is likely not to have more than one color and not have a uniform texture.
Contrarily, we are told that the sample is uniform in color and texture. This means that it is clearly not a heterogeneous mixture. We do not have enough information tell if the sample is a compound or an element.
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Which best explains why an electric toaster is considered a resistor?
It increases the flow of electrons.
It acts as a conductor.
It converts electric energy to another form of energy.
It produces an increase in voltage within the current.
Hi There!!
Your best answer choice is:
C. It converts electric energy to another form of energy.
Because, A electric toaster is considered a resistor because it coverts some of it energy into another form which is heat. a resistor is something that limits the flow of an electric current through a circuit.
[tex]GoodLuck!![/tex]
[tex]_{Loserbrazts}[/tex]
An electric toaster is considered a resistor because it converts electric energy to another form of energy. Therefore, the correct option is option C.
What is resistor?A "resistor" is a passive components electric device that is utilized to limit and regulate the electric current that flows in electrical circuits. It also allows us to provide a variable amount of resistance to something like an electrical circuit. Resistors are the most significant and widely utilized components in an electrical circuit.
The primary function of a resistor would be to decrease current flow but also voltage inside a specific area of the circuit. It is constructed of copper wires wound around with a ceramic rod and covered with insulating paint. Toaster converts electric energy to another form of energy.
Therefore, the correct option is option C.
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What type of reaction involving stolen methylamine does Walter White use in the hit TV show Breaking Bad, in order to synthesize the dangerous drug methamphetaminr?A. Grignard reaction.B. Electrophilic Aromatic Substitution.C. Reductive amination.D. Diels-Alder.
Answer:
C. Reductive amination.
Explanation:
Walter white used reductive animation reaction to synthesize methanphetaminr. In this type of reaction, we would have ammonia reacting with ketoglutaric acid and the result would be a formation of glutamic acid. This reaction process is an important way of making amines. Many amines made in pharmaceuticals are done by this method.
How many atoms are there in 3.559*10^-6 mol of krypton?
Answer:
The answer is
[tex] 2.143 \times {10}^{18} \: \: atoms[/tex]Explanation:
To find the number of atoms given the number of moles we use the formula
N = n × L
where
N is the number of entities
n is the number of moles
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
[tex]n = 3.559 \times {10}^{ - 6} \: mol[/tex]
Substitute the values into the above formula and solve
That's
[tex]N = 3.559 \times {10}^{ - 6} \times 6.02 \times {10}^{23} \\ = 2.1425 \times {10}^{18} [/tex]We have the final answer as
[tex]N = 2.143 \times {10}^{18} \: \: atoms[/tex]Hope this helps you
A block of aluminum occupies a volume of 17.8 mL and weighs 51.3 g. What is its density?
Answer:
2.88 g/mL
Explanation:
density = mass/volume
= 51.3/ 17.8
=2.88 g/mL
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10 POINTS : What are 4 things created from Big Bang?
Answer:
:0
Explanation:
One second after the Big Bang, the universe was filled with neutrons, protons, electrons, anti-electrons, photons and neutrinos.Jun 17, 2017
Give one example of a Phase Change
3/5 of 1 1/9 + 3 1/2
Answer: 4 1/6
Explanation: 3/5x1 1/9=2/3. 2/3+3 1/2=4 1/6.
A student performs a chemical reaction with vinegar and an antacid tablet. Experimental results are displayed in the table
below.
Before Chemical Reaction
Mass of Vinegar (9)
Mass of Antacid Tablet (g)
75.83
1264
After Chemical Reaction
Mass of Chemical Reaction (kg)
ODBB7
1 Explain how this chemical reaction represents the law of conservation of matter.
The mass
Answer:
Explanation:
Please tell me if im wrong
Question 6. 6. In a reaction between vinegar and antacid tablets, the antacid is the limiting reagent. At constant pressure and temperature, three tablets produce 600 cm3 of gas. What volume will two tablets produce?
(Points : 3)
400 cm3
600 cm3
800 cm3
1,200 cm3****
Question 7. 7. You breathe in 3.0 L of pure oxygen at 298 K and 1,000 kPa. How many moles of oxygen did you take in? (Use the ideal gas law: PV = nRT where R = 8.31 L-kPa/mol-K.)
(Points : 3)
0.05 moles
1.21 moles*****
2.42 moles
20.0 moles
Question 8. 8. Consider a gas at STP in a container of 22.4 L. If you apply the ideal gas law, what is the approximate value of n?
(Points : 3)
0.5
8.31
224****
1
Question 9. 9. Water boils at 100°C. What is that temperature on the Kelvin scale?
(Points : 3)
213 K
325 K****
333 K
373 K
Question 10. 10. The average speeds of gas molecules in cylinders A, B, C, and D are 0.001 m/s, 0.05 m/s, 0.1 m/s, and 0.5 m/s, respectively. Which cylinder contains gas that is closest to absolute zero?
(Points : 3)
A
B
C******
D
I suck at chemistry
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If there is a chemical change it will remain the same properties because a new substance was formed
Which of these tasks falls under the responsibility of a forensic scientist?
Cleaning the crime scene after evidence has been collected
Determining whether or not a suspect is guilty of the crime
Examining and signing petitions for search warrants
Training officers in how to properly collect evidence
Answer:
Training officers in how to properly collect evidence
Explanation:
Forensic science is an interesting branch of science that involves the use of scientific procedures to solve a crime case. It encompasses collection of physical evidence from the crime scene and analyzing it in a laboratory using scientific means.
A forensic scientist is the individual in charge of performing these scientific procedures. His/her major role is to run the scientific analysis of the physical evidence brought in by the officers, however, he/she can also perform the task of training officers in how to properly collect evidence, in order not to damage the evidence or render it invalid for use.
a compound contains 70.0 or iron and 30.1 oxygen what is its empirical formula
Answer:
The empirical formula would be Fe2o3
Explanation:
you first take the grams or the percent of each element, then transform them from grams to moles.
After getting the number of mols you want to divide each mol by the lowest number of mol.
EX) for this problem the number of moles of Fe(iron) would be 1.253 mol and the moles for the oxygen would be 1.881 mol... so you take the lowest, 1.253, and divide both to get what's called a mol fraction.
1.253/ 1.253 =1Fe
1.881/ 1.253= 1.5
now we want a whole number since we're finding the formula of a compound... and since there is a 1.5 you would multiple that by 2 giving you 3 for oxygen and giving you 2 for iron.
then these whole numbers will give you the subscripts that's needed for your empirical formula :)
- Hope this helps!!!
5. Work this problem involving scientific notation:
The mass of a proton (M)is 0.000 000 000 000 000 000 000 000 001 673 kg. The mass of a neutron (M)is 0.000 000 000 000 000 000 000 000 001 675 kg. Convert each mass to
scientific notation, then calculate the difference in mass between the two particles.
2.000 x 10-20 kg
2.000 x 105 kg
2.000 x 10-kg
2.000 x 10-kg
2.000 10-kg
Answer:
The answer would be 2.000 x 10^-30
Explanation:
I had taken the test and got it correct.
What are the best practices while sharing a lab balance with other students? Select one or more: Leave a note when you have tared a balance for your glassware. Brush off any chemical dust around the balance after each use. Alert your TA or instructor about any issues with the balance. Place samples directly onto the balance.
Answer:
Brush off any chemical dust around the balance after each useAlert your TA or instructor about any issues with the balanceExplanation:
The best practices while sharing a lab balance with other students includes alerting your TA or instructor about issues with the balance and Brushing off any chemical dust around the balance after each use. the practices will help to avert/reduce the work hazards associated with working with a balance.
Brushing off any chemical dust after each use will reduce the chemical hazards in the lab while Alerting your instructor about any issues with the balance helps to eliminate mechanical hazards that a faulty balance can pose
The average volume of a cotton ball is about 5.50 mL. If the mass of the cotton ball is 8.53 g, what is the density of cotton?
Answer:
Explanation:
5.5 I believe.
Sulfur tetrafluoride, SF4, has a mass ratio of sulfur to fluorine of 1.00 : 2.37. A second, unknown compound containing sulfur and fluorine has a sulfur to fluorine mass ratio of 1.00 : 3.55. Use the law of multiple proportions to determine the chemical formula of the unknown compound.
Answer:
The formula of the unknown compound = SF₆
Explanation:
The law of multiple proportion states that if two elements A and B combine to form more than one compound, then the various masses of A which combine with a fixed mass of B are in simple multiple ratio.
In the compound SF₄, the mass ratio of sulfur to fluorine is 1.00 : 2.37
In the unknown compound, the mass ratio of sulfur to fluorine is 1.00 : 3.55
Since the number of sulfur atoms in the two samples are fixed;
The ratio of fluorine in the unknown sample and SF₄ = 3.55/2.37 = 3/2
Therefore, the number of fluorine atoms in the unknown sample = 4 * 3/2 = 6 atoms
The formula of the unknown compound = SF₆
The formula of the unknown compound = SF₆
The calculation is as follows:In the compound SF₄, the mass ratio of sulfur to fluorine is 1.00 : 2.37
In the unknown compound, the mass ratio of sulfur to fluorine is 1.00 : 3.55
Since the number of sulfur atoms in the two samples are fixed;
Now
The ratio of fluorine in the unknown sample and SF₄ = [tex]3.55\div 2.37 = 3\div 2[/tex]
So, the number of fluorine atoms in the unknown sample should be
= [tex]4 \times 3\div 2 [/tex]
= 6 atoms
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PLZ HELP CHEMISTRY! WILL REWARD! Please correct me if I'm wrong.
I marked my answers as x.
1. During a titration, 50.0 ml of 0.2M NaOH were required to neutralize 50.0ml of H3PO4. What's the concentration of the H3PO4 solution?
A. 1.8M
B. 0.6M
C. 0.07M
x D. 0.2M
2. Attached photo - Using the two cell reduction potentials shown for their corresponding reaction, calculate the cell potential for a voltaic cell made from these two systems.
A. –1.68 V
B. –0.78 V
C. 0.78 V
D. 1.68 V
3. If atoms from two different elements react to form a compound, the element with a higher _______ will have a negative oxidation number.
A. atomic number
B. atomic radius
C. energy
x D. electronegativity
4. During the electrolysis of an aqueous solution of sodium nitrate, a gas forms at the anode, what gas is it?
x A. Oxygen
B. Hydrogen
C. Sodium
D. Water
5. The lithium-ion in a lithium-ion battery moves from one side to the other by
A. moving through the cathode.
B. moving through the anode.
x C. passing through the separator.
D. passing through the device.
6. The use of water in a heat exchanger is taking advantage of water's
x A. high specific heat.
B. significant expansion during boiling.
C. solid state when frozen.
D. polar molecular nature.
Which of the following goes through the largest volumetric change?
A. Water when it boils into steam
x B. Water when it freezes into ice
C. Water when it's heated from 1oC to 99oC
D. Ice when it melts into water
Explanation:
1. During a titration, 50.0 ml of 0.2M NaOH were required to neutralize 50.0ml of H3PO4. What's the concentration of the H3PO4 solution?
Answer:
Using CaVa / CbVb = Na / Nb. The correct option is D.
3. If atoms from two different elements react to form a compound, the element with a higher _______ will have a negative oxidation number.
Answer:
The correct option is electronegativity. For example, in H2O. Oxygen would have a negative oxidation number of -2 because it is highly electronegative compared to hydrogen. Also, a negative oxidation number means it gains electrons.
4. During the electrolysis of an aqueous solution of sodium nitrate, a gas forms at the anode, what gas is it?
Answer:
At the anode, OH- ions are preferentially discharged. They lose electrons there and form oxygen gas. The correct option is A. Oxygen
5. The lithium-ion in a lithium-ion battery moves from one side to the other by
Answer:
The correct option is passing through the separator. The lithium ions, moves from the anode to the cathode when in use.
6. The use of water in a heat exchanger is taking advantage of water's
Answer:
The correct option is it's High specific heat capacity. Since heat exchangers requires transfer of heat, there is need for a medium that is able to carry this heat. The hydrogen bonds in water provides it with an abnormal high specific heat capacity.
7. Which of the following goes through the largest volumetric change?
Answer:
Whenever ice melts it occupies the same energy as when it was frozen. When water is heated from 1oC to 99oC there is no change in volume. Volume of water increases abruptly at it boils at 100oC and changes its state from liquid water to steam. When water freezes it's volume increases by approximately 9%. The correct option is A.
Kindly Note:
Next time, You don't have to ask everything in a single question. Nobody would want to go through the stress of answering them all. I omitted number 2 intentionally.
What happens to nonpolar molecules in water?
Answer:
B) They aggregate together.
Explanation:
A nonpolar molecule refers to a molecule in which there is no charge separation that means no positive or negative poles are created
Also it cannot create the bonds of hydrogen with the water molecules that results in the disturbance of normal structure of water that makes the water to create a fixed cage of molecules that are hydrogen bonded around it
Therefore in the given case, the option B is correct
Why is Jupiter so much larger than earth ? Check all that apply .
Answer: Its so much larger because it has a core.
Explanation:
Jupiter is proven to have a core, the planet still could have formed that core through disk instability. Enough dust could have collected and cemented together in the dense gas to form a core many times larger than the size of the Earth
Answer:
Inner planets were created at higher velocities. Outer planets attracted helium, hydrogen, and other gasses and Gases escaped from inner planets and not from outer ones.
Explanation:
A box has dimensions 0.2 mx 0.4 m x 0.6 m. What is the
volume of the box in cubic meters? Round to the nearest
hundredths.
Answer:
[tex]V=0.048m^3[/tex]
Explanation:
Hello,
In this case, since the volume is computed by multiplying the given dimensions as follows:
[tex]V=0.2m*0.4m*0.6m[/tex]
The result is shown in cubic meters since each meter is also added:
[tex]V=0.048m^3[/tex]
Best regards.
Why is air considered a homogeneous mixture
Explanation:
Because each layer of the Earth's atmosphere has a different density, each layer of air is its own homogeneous mixture.
