Answer: The molecular weight of tris buffer is 121 g/mol
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.
[tex]Molarity=\frac{n}{V_s}[/tex]
where,
n = moles of solute
[tex]V_s[/tex] = volume of solution in L
moles of tris buffer = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{12.1g}{Mg/mol}[/tex]
Now put all the given values in the formula of molality, we get
[tex]0.1=\frac{12.1g}{Mg/mol\times 1L}[/tex]
[tex]M=121g/mol[/tex]
Therefore, the molecular weight of tris buffer is 121 g/mol
the ph of a naoh solution is 12.05. what is the concentration of [oh-] of the naoh solution? express your answer in standard notation
Answer:
0.01 M
Explanation:
NaOH (sodium hydroxide) is a strong base, so it is completely dissociated into ions in aqueous solution:
NaOH ⇄ Na⁺ + OH⁻
So, we have OH⁻ ions in solution.
From the problem, we have the pH value. The pH is calculated as:
pH = -log [H⁺]
As NaOH is a base, we can also calculate the pOH:
pOH = -log [OH⁻]
Thus. we can use the relation between pH and pOH to calculate the pOH and then use it to calculate [OH⁻]:
pH + pOH = 14 ⇒ pOH = 14 - pH = 14 - 12.05 = 1.95
pOH = -log [OH⁻] ⇒ [OH⁻] = [tex]10^{-pOH}[/tex]= [tex]10^{1.95}[/tex]= 0.0112 M ≅ 0.01 M
Answer:
0.0112
Explanation:
They said that was the answer.
Which statement best describes a heart attack?
A. Certain blood vessels expand
B. Certain blood vessels shrinks
C. Blood vessels are normal
D. Certain blood vessels are blocked by fatty acids
Answer:
I think number D is correct
Answer:
D. Certain blood vessels are blocked by fatty acids
Explanation:
A heart attack occurs when the flow of blood to the heart is blocked. The blockage is most often a buildup of fat, cholesterol and other substances, which form a plaque in the arteries that feed the heart (coronary arteries). Sometimes, a plaque can rupture and form a clot that blocks blood flow.
In the carbon cycle, carbon is transferred from animals to plants by which of the following?
A. carbon dioxide
B. oxygen
C. sugars
D. water
Answer:
A carbon dioxide
its how carbon is transferred
Carbon cycle is the process of balancing the amount of carbon in the atmosphere and what is present in plants and animals. In carbon cycle, carbon is transferred in the form of carbon dioxide from animals to plants.
What is carbon cycle?Carbon cycle is a geochemical cyclic process by which the carbon gas is exchanged between the atmosphere and biosphere. Carbon is the main content of all biological materials as well as living.
These events in carbon cycle balance the amount of carbon in atmosphere and biosphere to sustain life. Thus the wasted carbon from animals are recycled back to the atmosphere in the form of carbon dioxide.
We intake oxygen and release carbon dioxide. The released carbon dioxide is uptaken by plants and used for photosynthesis. By the process of photosynthesis, plants are making glucose and energy.
Therefore, In the carbon cycle, carbon is transferred from animals to plants in the form of A. carbon dioxide.
To find more about carbon cycle, refer the link below;
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The breakdown of a certain pollutant X in sunlight is known to follow first-order kinetics. An atmospheric scientist studying the process fills a 20.0Lreaction flask with a sample of urban air and finds that the partial pressure of X in the flask decreases from 0.473atm to 0.376atm over 5.6hours.
Calculate the initial rate of decomposition of X, that is, the rate at which Xwas disappearing at the start of the experiment.
Round your answer to 2 significant digits.
Answer:
0.019 atm / hr
Explanation:
Initial Concentration (Pressure) [A]o = 0.473 atm
Final Concentration (Pressure) [A] = 0.376 atm
Time = 5.6 hours
The breakdown follows first order kinetics.
The integrated rate law for a first order reaction is given as;
ln[A] = ln[A]o - kt
ln(0.376) = ln(0.473) - k (5.6)
ln(0.376) - ln(0.473) = - 5.6 k
5.6 k = 0.23
k = 0.0411 hr⁻¹
The rate of decomposition is given as;
Rate = k [X]
Where [X] represents Concentration (Pressure) = 0.473 atm
Rate = 0.0411 * 0.473 = 0.019 atm / hr
DNA forms two strands. One of the strands of a piece of a DNA molecule has the bases ATA.
Which bases does the other strand have?
Select one:
A: CAC.
B: TAT.
C: GTG.
D: ATA.
Answer:
b
Explanation:
Combinations between two strands:
T - A
A - T
C - G
G - C
(so if one strand has A for example, then the other strand must have T in the same spot)
Bases which are present on the other strand of DNA are TAT.
What is DNA?DNA or deoxyribonucleic acid is a hereditary material present in humans as well as all living beings. Almost every cell present in the body has DNA. Most DNA are located inside the cell , that is in the nucleus of the cell. But a small portion of DNA can be found in the mitochondria of the cell as well.
The information in DNA is stored as a code which is composed of four chemical bases 1) adenine 2)guanine 3) cytosine 4) thymine . The human DNA consists of 3 billion bases . The order of of these bases determine information which is used for building and maintaining an organism.
The DNA bases can pair with each other .Adenine pairs with thymine and guanine with cytosine to form units which are called as base pairs.Each base apart from other complementary base it also attaches itself to a sugar and a phosphate molecule.
Learn more about DNA ,here:
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If you were to mass the reactants before the reaction and then mass the products after the reaction,what would you expect to find? Why? How is this related to balancing your equations?
Explanation:
What would you expect to find?
- The masses of the reactants would be equal to the masses of the product.
Why?
- This is due to the law of conservation of matter which states that matter is neither created nor destroyed in an isolated system but converted from one form to the other.
How is this related to balancing your equations?
- This is why during balancing of equations, we must ensure that the number of atoms in the reactant side must be equal to the number of atoms in the product side.
What is the surface composition of planets in the solar system?
A,. Helium or hydrogen
B,. Rock or gas
C., Rock or water
D,. Water or helium
Answer:
B
Explanation:
Most planets in the solar system don't have water. Helium and hydrogen are two of the many gasses in planets. Therefore, B is the best answer.
The level of a liquid (i.e. distilled water) in laboratory glassware is determined by sight. The level corresponds to a specific volume. The volume is established by identifying the meniscus of the liquid relative to a calibration mark or series of calibration marks on the glassware (ie. volumetric flask vs. buret). Which of the following statements is NOT correct when reading the meniscus?
a. The edge of the meniscus should be used to determine volume relative to the mark or marks
b. The meniscus should be read at eye level
c. When the meniscus is between marks, estimate the reading to the nearest tenth of a division (ie, estimate to 0.01 mL if buret has 0.1 ml divisions)
d. The center of the meniscus should be used to determine volume relative to the mark or marks
Answer:
c. When the meniscus is between marks, estimate the reading to the nearest tenth of a division (ie, estimate to 0.01 mL if buret has 0.1 ml divisions)
Explanation:
The meniscus is the mark that a liquid presents in a pipette. This measure is important for determining the volume of a solution, allowing the correct amounts of aqueous solutions to be used. The meniscus must be observed at eye level to avoid parallax errors. In this view, the border and center of the meniscus must be considered to determine the volume.
Which food dyes in the diagram on the right only contain one colour?
( Science, Chromatography )
H.w. balance the following equations:
a) Iron + chlorine → Iron (iii) chloride
b) Nitrogen + hydrogen → Ammonia
c) Phosphoric acid + sodium carbonate → sodium phosphate + water + carbon dioxide
d) Nitrogen dioxide + water + oxygen → Nitric acid
Answer:
3iron + chlorine=iron3 chloride
nitrogen +3hydrogen
Answer:
a) Iron + chlorine → Iron (iii) chloride
3fe+cl__fe3cl
b) Nitrogen + hydrogen → Ammonia
2N+3h2------2NH3
c) Phosphoric acid + sodium carbonate → sodium phosphate + water + carbon dioxide
2H3PO3+3Na2CO3-----2Na3PO4+3H2O+3CO2
d) Nitrogen dioxide + water + oxygen → Nitric acid
NO2+H2O+O2--NOH
sorry if mistake
What is the product of the first beta decay in this series?
A)
AC-227
B)
Ac 228
Ra-227
D
Rn 224
Answer:
B)
Explanation:
In beta decay the nucleus loses a neutron and gains a proton. The mass therefore remains constant but the atomic number increases by one.
The hybridisation of the central atom in ICL-2
a) sp.
b) sp2
c) sp3d d)sp3
Explanation:
For ICl²-, the central iodine atom is bonded to the 2 chlorine atoms and has 3 lone electron pairs.
Altogether it has 5 electron domains, which means it is sp3d hybridized. (C)
9. The role of an organism in an ecosystemis called alan
O A. habitat
O B. niche
O C. evolution
D. community
Am I correct?
As gravity/distance increases between two objects, the gravitational pull between them weakens/strengthens
Yes, As the gravity/distance increases between two objects, the gravitational pull between them weakens/strengthens.
Explanation:There is a gravitational force of attraction between every object in the universe. The size of the gravitational force is proportional to the masses of the objects and weakens as the distance between them increases.
Skin color variations were caused by:
a). The change in melanin, the skin's brown pigment
b). The climate of where people migrated to
c)Diets that are rich in Vitamin D
d) All of the above
I'm certain the answer is D: All of the above, but please correct me if I'm wrong ^^
A certain liquid X has a normal boiling point of 129.90°C and a boiling point elevation constant =Kb= 1.67°C·kgmol^−1. Calculate the boiling point of a solution made of 90.g of iron(III) chloride (FeCl3) dissolved in 650.g of X.
Answer:
Boiling T° of solution = 135.6°C
Explanation:
Formula for elevation boiling point is:
ΔT = Kb . m . i
ΔT = Boiling point of solution - Boiling point of pure solvent
Kb = Boiling point elevation constant
m = molality → moles of solute in 1kg of solvent
i = numbers of ions dissolved
FeCl₃ → Fe³⁺ + 3Cl⁻
In the dissociation of the ionic salt, we determined 4 moles of ions dissolved.
3 for chlorides and 1 for iron. Then i = 4
m → We convert the mass of solute to moles:
90 g . 1mol / 162.2g = 0.555 moles
650 g of solvent = 0.650 kg of solvent
m = 0.555 mol/0.650kg → 0.85
We replace data at formula
Boiling T° of solution - 129.90°C = 1.67°C . kg/mol . 0.85 mol/kg . 4
Boiling T° of solution = 1.67°C . kg/mol . 0.85 mol/kg . 4 + 129.90°C
Boiling T° of solution = 135.6°C
which is the command center of the body
Answer:
nervous system
or u can say brain too
Explanation:
hope this is what u want
Answer:
Your nervous system is your body's command center.
Explanation:
since it is originated from your brain, it controls your movements, thoughts and automatic responses to the world around you.
Describe how naturally
acidic rainwater can affect a
mountain of limestone.
Answer:
The naturally acidic rain will gradually wear the mountain of limestone away.
Hope it helps!
२
1. A ratio of the parts of a mixture are exact true or false.
PLEASE HURRY. This is a project please help me as soon as possible.
1. What do you think would have happened if the light pollution had been a permanent condition
on planet Oopsa?
2. What do you think would have happened if the light pollution were green instead of red?
Please help asap. Will give brainliest.
Answer:
Light pollution is excessive, misdirected or inappropriate outdoor lighting. Too much light pollution washes out the view of the Universe, increasing energy consumption, interferes with astronomical research, disrupts ecosystems, and affects the health and safety of humans and wildlife.
Explanation:
Light pollution radically alters their nighttime environment by turning night into day. ... “Predators use light to hunt, and prey species use darkness as cover,” Kyba explains “Near cities, cloudy skies are now hundreds, or even thousands of times brighter than they were 200 years ago.
Compare the cycling of water and nutrients through an ecosystem to the cycling of blood in your cardiovascular system. What is the source of energy in each case?
The cycling of water and nutrients through an ecosystem is powered mainly by the sun, while the cycling of blood in the cardiovascular system "powered" by the heart.
Hope this helps!
The ecosystem has been the correlation between the biotic and abiotic components in the specified area.
The cardiovascular system has been the organ system comprising heart, arteries and veins. It functions to carry blood.
Cycling of water, nutrients, and bloodThe water and nutrients in the ecosystem are absorbed and converted to another form and return to the original form. This has been known as the cycle of the water.
The water in the stream and ocean has been converted to the vapor form. It has been evaporated by the energy of sun.
The evaporated vapors have been converted to the clouds by condensation, and the precipitation results in the poring of water again to the stream and ocean.
The circulation in the body has been mediated in the same way as the water cycle. The blood has been pumped from the heart.
The veins carry the blood to different tissues and cells. It has been used, and carried back from the cells to the heart.
Learn more about water cycle, here:
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Given this balanced equation:
1 Cu + 1 H2SO4 -> 1 CuSO4 + 1 H2
If you have 22.45 moles of H2SO4 , how many mole of CuSO4 can you make?
Answer value
Mercury can be obtained by reacting mercury(II) sulfide with calcium oxide. How many grams of Mercury metal are produced when 2.11 g of calcium oxide reacts with excess mercury(II) sulfide?
4HgS+4CaO=4Hf+3CaS+CaSO4
a. 10.1 g
b. 1.80 g
c. 13.4 g
d. 7.56 g
Answer:
Option D. 7.56 g of Hg.
Explanation:
The balanced equation for the reaction is given below:
4HgS + 4CaO —> 4Hg + 3CaS + CaSO₄
Next, we shall determine the mass of CaO that reacted and the mass of Hg produced from the balanced equation. This is can be obtained as follow:
Molar mass of CaO = 40 + 16
= 56 g/mol
Mass of CaO from the balanced equation = 4 × 56 = 224 g
Molar mass of Hg = 200.59 g/mol
Mass of Hg from the balanced equation = 4 × 200.59 = 802.36 g
SUMMARY
From the balanced equation above,
224 g of CaO reacted to produce 802.36 g of Hg.
Finally, we shall determine the mass of Hg produced by the reaction of 2.11 g of CaO. This can be obtained as follow:
From the balanced equation above,
224 g of CaO reacted to produce 802.36 g of Hg.
Therefore, 2.11 g of CaO will react to produce = (2.11 × 802.36)/224 = 7.56 g of Hg.
Thus, 7.56 g of Hg were obtained from the reaction.
the Rockies and the Appalachians are two major mountain ranges in the United States. Which type of plate movement caused these mountain ranges to form
Answer:
Convergent
Explanation:
I don't know whether this is one of your answers but It is convergent because convergent boundaries are when two plates collide against each other which can create mountains and volcanos.
Every orbital in a sub level is singly occupied before any orbital is doubly occupied is the statement of
Answer:
Hund's rule of maximum multiplicity
what is the fundamental building unit
Answer:
The basic building blocks that make up matter are called atoms.
I hope it's helpful!
When benzene is treated with 2-methylpropene and sulfuric acid, the product obtained is tert-butylbenzene. Propose a mechanism for this transformation. For the mechanism, draw the curved arrows as needed. Include lone pairs and charges in your answer.
Answer:
See explanation and image attached
Explanation:
This reaction begins when the pi bond in 2-methylpropene is attacked by a proton. A tertiary carbocation is formed which now may attack a benzene ring in an electrophilic reaction. A tertiary carbocation is very stable.
The electrophilic attack of the tertiary carbocation yields the final product tert-butylbenzene as shown in the image attached.
Why parafin oil use in melting
Answer:
Paraffin oil is used for determination of boiling point and melting point for the following reasons: It has a very high boiling point and so it can be used to maintain high temperatures in the boiling and melting point apparatus without loss of the substance.
A computer randomly puts a point inside the rectangle. What is the probability
that the point does not land in triangle T?
8
4
4
S
LO
T
2
7
O A.
O B. 13
C. }
CON 002
D.
3
Answer:
c
Explanation:
is C2Br2 ionic or covalent