Tris is a molecule that can be used to prepare buffers for biochemical experiments. It exists in two forms: Tris (a base) and TrisH (an acid). The MW of Tris base is 121.14 g/mol; the MW of TrisH is 157.6 g/mol (the extra weight is due to the Cl- counterion that is present in the acid). The Ka of the acid is 8.32 X 10-9. Assume that you have TrisH in solid form (a powder), unlimited 1M HCl, unlimited 1 M NaOH and an unlimited supply of distilled water. How would you prepare 1 L of a 0.02 M Tris Buffer, pH
Solution :
The reaction :
[tex]$\text{TrisH}^+ + \text{H}_2\text{O} \rightarrow \text{Tris}^- +\text{H}_3\text{O}^+$[/tex]
We have
[tex]$K_a = \frac{[\text{Tris}^-]\times[\text{H}_3\text{O}^-]}{[\text{TrisH}^+]}$[/tex]
[tex]$=\frac{x^2}{0.02-x}$[/tex]
[tex]$= 8.32 \times 10^{-9}$[/tex]
Clearing x, we have [tex]$x=1.29 \times 10^{-5}$[/tex] moles of acid
Now to reach pH = [tex]$7.8 (\text{ pOH} = 14-7.8 = 6.2)$[/tex], we must have an [tex]$OH^-$[/tex] concentration of
[tex]$[OH^-] = 10^{-pOH}$[/tex]
[tex]$=10^{-6.2}$[/tex]
[tex]$=6.31 \times 10^{-7}$[/tex] moles of base
We must add enough NaOH of 1 M to neutralize the acid calculated above and also add the calculated base.
[tex]$n \ NaOH = 1.29 \times 10^{-5} + 6.31 \times 10^{-7}$[/tex]
[tex]$=1.35 \times 10^{-5}$[/tex] moles
Vol [tex]$NaOH = 1.35 \times 10^{-5} \text{ moles} \times \frac{1000 \ mL}{1 \ mol}$[/tex]
= 0.0135 L
Tris mass [tex]$H^+ = 0.02 \text{ mol} \times 157.6 \ g/mol$[/tex]
= 3.152 g
To prepare the said solution we must mix
-- [tex]$3.152 \ g \text{ TrisH}^+$[/tex]
-- [tex]$0.0135 \ mL \ NaOH \ 1M$[/tex]
-- [tex]$\text{Gauge to 1000 mL with H}_2\text{O}$[/tex]
A substance that dissolves in a solvent is said to be a(n)
A. immiscible
B. miscible
C. soluble
D. insoluble
Answer:
C. soluble
Explanation:
Remember that a substance that dissolves in a solvent is said to be soluble in that solvent. A substance that does not dissolve in a solvent is insoluble. Process of Dissolving: Solvent particles surround solute particles to form a solution in a process called solvation.
Which units can be used to measure length or distance? Check all that apply.
gram
meter
kilometer
liter
inch
Answer:
Meter, kilometer & inch - used to measure length or distance.
Unknown compound Q is spotted on a TLC plate that is then developed in dichloromethane. The solvent front is measured at 5.2 cm and the distance traveled by compound Q is measured at 3.4 cm. A sample of aspirin is spotted on a TLC plate that is then developed in dichloromethane. The solvent front is measured at 4.15 cm and the distance traveled by aspirin is measured at 2.70 cm. What can be determined about the identity of compound Q in light of this data
Answer:
Follows are the solution to the given question:
Explanation:
The Rf value on the Q is =0.65
The Rf value in the acetaminophen is =0.651
In this question, its identity the Q is probably in the acetaminophen since the value which is used to calculates, and however almost the same, and it is used to ensure the other document which is the substances, that are evaluated.
How many grams of air are required to complete the combustion of 120 g of phosphorous to diphosphorous pentoxide, assuming the air to be 23% oxygen by mass?
Answer:
Explanation:
522 g
Explanation:
Your starting point here will be the balanced chemical equation for this combustion reaction
4
P
(s]
+
5
O
2(g]
→
2
P
2
O
5(s]
Notice that you have a
4
:
5
mole ratio between phosphorus and oxygen. This means that, regardless of how many moles of phosphorus you have, the reaction will always need
5
4
time more moles of oxygen gas.
Use phosphorus' molar mass to determine how many moles you have in that
93.0-g
sample
93.0
g
⋅
1mole P
30.974
g
=
3.0025 moles P
Use the aforementioned mole ratio to determine how many moles of oxygen you would need for many moles of phosphorus to completely take part in the reaction
3.0025
moles P
⋅
5
moles O
2
4
moles P
=
3.753 moles O
2
An example of a suspension is:
A. blood
B. gelatin
C. muddy water
D. milk
PLEASE HELP ME!!! i have no idea how to answer these!
Answer: Im answering this for points
DONT COME ON MY STUFF SAYING THAT I GOT SCHOOL TO DO JUST LIKE YOU AND YOUR GIVING ME IRRELEVANT ANWSERS JUST TO GET POINTS? THATS A WASTE OF MY TIME
Explanation:
What enzyme catalyses the reaction of PRPP transfer to hypoxanthine with
formation of IMP?
Answer:
HPRT
Explanation:
HPRT catalyzes the salvage reactions of hypoxanthine and guanine with PRPP to form IMP and GMP
The formation of GMP from IMP requires oxidation at C-2 of the purine ring, followed by a glutamine-dependent amidotransferase reaction that replaces the oxygen on C-2 with an amino group to yield 2-amino,6-oxy purine nucleoside monophosphate, or as this compound is commonly known, guanosine monophosphate.
Select the correct answer.
Which of these is always equal to the molar mass of any element?
OA
its atomic number
B.
its atomic weight
OC.
its atomic formula
OD.
its atomic structure
Answer:
a t o m i c w e i h g t
B
Explanation:
a to m i c w e i g h t
Please help me thanks
Answer:
an imbalance of positive and negative charges
Explanation:
Answer:
hope it help s answer circle 3
If a pure compound is distilled, the head temperature will be____compared to the pot temperature. If however, an impurity is present that strongly interacts with the liquid molecules, then the____has to be increased in order to increase the vapor pressure of the liquid, ultimately to____atmospheric pressure, allowing the liquid to boil. Thus, at boiling point, the pot temperature will be____from that of the head temperature.
Answer:
If a pure compound is distilled, the temperature of the head will be compared to the temperature of the pot. However, if there is an impurity present that strongly interacts with the molecules of the liquid, then the temperature must be increased to increase the vapor pressure of the liquid, eventually to atmospheric pressure, allowing the liquid to boil. Therefore, at the boiling point, the temperature of the pot will be higher than the temperature of the head.
Explanation:
when temperatures increase, pressures also do so, thus reaching boiling points where liquid states become gaseous.
Balance equation mg3n2+h2so4=mgso4+(nh4)2
Answer:
Mg₃N₂ + 4 H₂SO₄ ⇒ 3 MgSO₄ + (NH₄)₂SO₄
Explanation:
To balance an equation, you need to make both sides of the equation have equal number of each element. Also, I think that you didn't write the whole equation since the reaction you gave is not likely.
Mg₃N₂ + 4 H₂SO₄ ⇒ 3 MgSO₄ + (NH₄)₂SO₄
hi, if your looking for extra points (50+) and br ainiest here is ur chance, answer this question correctly plz
Answer:
Evaporation and condensation
Explanation:
why do you think season will impact the size of a rabbit population
Chemical energy is released when bonds blank in a chemical reaction
Answer:
form
Explanation:
Think about a hot summer afternoon at the beach
or a lake. How do the temperatures of the sand
and water compare?
A. The sand is hot; the water is cool.
B. The sand is hot; the water is hot.
C. The sand is cool; the water is cool.
D. The sand is cool; the water is hot.
Answer:
D
Explanation:
I say this because of this that I read. There was a study shown
"Our experiment was a success. We obtained data that answered our problem, “Which substance absorbs the most heat on a hot day? Sand, water, or sand with water?” The results showed that from the twenty-five trials: the cup of sand temperature ranged from 63-68°C, cup of water temperature ranged from 71-77°C, and the cup of sand with water temperature ranged from 66-71°C. Based on our data, our hypothesis was incorrect. We hypothesized that the sand would absorb the most heat since it is darker and less reflective than water; but from our data, water absorbed the most heat. In conclusion, sand absorbed the least amount of heat and water absorbed the most. Next time we want to cool down at the beach, we’ll know where to go!"
This was an experiment that was performed and this is the conclusion
Hope that helps
PLEASE HELP!!!
a person measures the mass of a 10cm3 rock to be 15g. what is the density of the rock
Answer:
[tex]d=1.5\ g/cm^3[/tex]
Explanation:
Given that,
The mass of the rock, m = 15 g
The volume of the rock, V = 10 cm³
We need to find the density of the rock. The density of an object is equal to the mass per unit volume such that,
[tex]d=\dfrac{m}{V}\\\\d=\dfrac{15\ g}{10\ cm^3}\\\\d=1.5\ g/cm^3[/tex]
So, the density of the rock is equal to [tex]1.5\ g/cm^3[/tex].
Oxygen gas was produced in a reaction and collected over water. A 136.1 mL mL sample of gas was collected over water at 25C and 1.06 atm. The vapor pressure of water is 23.76 mmHg at 25C. Find the mass of ocygen gas collected in a reaction and collected over water. A 136.1 mL sample of gas was collected over water at 25C and 1.06 atm. The vapor pressure of water is 23.76 mmHg at 25C. Find the mass of oxygen gas collected.
Answer:
Explanation:
We shall find volume of gas at NTP or at 273 K , 760 mm of Hg .
Pressure of given gas = 1.06 x 760 mm of Hg less vapor pressure of water .
= 805.6 - 23.76 = 781.84 mm of Hg
For it we use gas law formula ,
P₁V₁ / T₁ = P₂V₂ / T₂
781.84 x 136.1 / ( 273 + 25 ) = 760 x V₂ / 273
= 128.26 mL .
= 128.26 x 10⁻³ L .
22.4 L of oxygen will have mass of 32 g
128.26 x 10⁻³ L of oxygen will have mass of 32 x 128.26 x 10⁻³ / 22.4 g
= 183.22 mg .
Which of the following do scientists use to form a hypothesis?

A.
A question and observations

B.
A conclusion and data

C.
A conclusion and a theory

D.
A question and opinions
Explanation:
The scientific method involves making observations and asking questions. Scientists form hypotheses based on these observations and then develop controlled experiments to collecting and analyze data. Using this data, they are able to draw conclusions and form questions for new scientific research.
:)ᴍᴀʀᴋ ᴀꜱ ʙʀᴀɪɴʟɪꜱᴛ
If I began this reaction with 1.7g of O2 , how much water would I make
Calculate the molecular mass for the following: SnO2
Answer:
[tex]MM=150.71g/mol[/tex]
Explanation:
Hello there!
In this case, since the molar masses of chemical compounds allow us to understand the mass they have per mole of substance, for tin oxide, we can see it has one tin atom and two oxygen atoms; thus, for the calculation of this molar mass we multiply the atomic masses by the number of atoms and them add the results up:
[tex]MM=m_{Sn}+2m_O\\\\MM=118.71g/mol+2*16.00g/mol\\\\MM=150.71g/mol[/tex]
Best regards!
Generally, atmospheric pressure decreases by 1.00 mmHg as
altitude increases 10.0 m. If altitude increases 100. m, how
much would the atmospheric pressure change in atm?
Answer:
-0.0132 atm
Explanation:
Step 1: Calculate the atmospheric pressure change if altitude increases 100. m
Atmospheric pressure decreases by 1.00 mmHg as altitude increases 10.0 m. The decrease in pressure when the altitude increases 100. m is:
100. m × (-1.00 mmHg/10.0 m) = -10.0 mmHg
Step 2: Convert "-10.0 mmHg" to atm
We will use the conversion factor 1 atm = 760 mmHg.
-10.0 mmHg × 1 atm/760 mmHg = -0.0132 atm
During a hurricane, what effect can the ocean have on the beach?
Help pleaseee!!!Please explain how evaporation condensation and precipitation are involved in the water cycle
Answer: The water cycle shows the continuous movement of water within the Earth and atmosphere. ... Liquid water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow. Water in different phases moves through the atmosphere (transportation).
Explanation:
Answer:
water evaporates into water vapor, condenses to form clouds, and precipitates back to earth in the form of rain and snow.
Explanation:
evaporation, condensation, precipitation, and collection. condensation: this is when water vapor in the air cools down and turns back into liquid water. precipitation: this is when water (in the form of rain, snow, hail, or sleet) falls from clouds in the sky.
good luck :)
hopefully, this helps
have a great day !!
Pb(NO3)+MgI2=Mg(NO3)+PbI2 what type of reaction?
Pb(NO3) + MgI2 = Mg(NO3) + PbI2 is an example of a double-replacement reaction.
Which one of the following statements about the carbon phosphorus and nitrogen cycles is true ?
a. The major source of carbon used by plants is the soil
b. The major source of nitrogen used by plants is the air.
c. Phosphorus has no atmospheric component.
d. Bacteria drive the phosphorus cycle.
Answer: The correct option is C.
Phosphorus has no atmospheric component.
Explanation:
This is because, phosphorus is not in gaseous state but it is liquid at normal temperature, therefore it cannot be found in the air. It is cycle through water,soil or sediments. The major source of phosphorus in the phosphorus cycle is the rock. Rock contain phosphorus and phosphorus I'd gotten from rocks through weathering. Weathering is the disintegration of rocks into sediments or smaller particles. This is released into the soil after weathering.
milk milk milk........
Answer:
gimme that chocky milk.....
Explanation:
Answer:
m i l k
Explanation:
Which change represents an oxidation reaction?
Name the functional group in the
following molecule:
HSCH2CH3
A. alkane
B. amide
C. thiol
D. alkyl halide
Answer:
C. thiol
Explanation:
Answer:
it's C thiol I just took the test
hope this helps
have a good day :)
Explanation:
1. why do the elements within a group of the periodic table have similar chemical properties?
Answer:
the elements in a group have similar electron configurations, an elements electron configuration determines its chemical properties, therefore members of a group in the periodic table have similar chemical properties. ... These metals have a single valence electron and are extremely reactive.
Explanation:
Answer:
Because they all have one or more atoms of the same type material
Explanation: