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]
Which body system provides protection of the brain and the spinal cord?
Answer:
The bones of the skull and spinal column
Explanation:
The central nervous system is better protected than any other system or organ in the body. Its main line of defense is the bones of the skull and spinal column, which create a hard physical barrier to injury.
Answer:
The Central Nervous System (CNS)
Using Graham's Law of Effusion, calculate
the approximate time it would take for
1.0 L of argon gas to effuse, if 1.0 L of
oxygen gas took 12.7 minutes to effuse
through the same opening.
0.070 minutes
0.89 minutes
None of the other answers
14 minutes
12 minutes
The rate of effusion of Argon here is 8.03 min
Data;
Molar mass of Oxygen = 16g/molTime for effusion of oxygen = 12.7 minMolar mass of Argon = 40g/molTime for effusion of Argon = ?Graham's Law of EffusionThis law states that the rate of effusion of a gas is inversely proportional to the square root of it's molar mass.
[tex]R \alpha \frac{1}{\sqrt{M} }[/tex]
From this,
[tex]\frac{r_1}{r_2} = \frac{\sqrt{M_2} }{M_1}[/tex]
substituting the values and solving,
[tex]\frac{R_A_r}{12.7}= \frac{\sqrt{16} }{\sqrt{40} } \\ R_A_r = \frac{12.7*\sqrt{16} }{\sqrt{40} } \\R_A_r = 8.032min[/tex]
The rate of effusion of Argon here is 8.03 min
Learn more on Graham's law of effusion here;
https://brainly.com/question/12211278
1) How many molecules are in 0.02 moles of beryllium iodide?
Answer:
3 grams??
Explanation:
I think this would be the answer you are looking for.
(22 points) please please help me thanks so much
Answer:
d
Explanation:
Answer:
hopen it helps soo much thanks for the points
g The alkali metals are able to displace hydrogen readily from water. The alkaline earth metals are able to do so as well, although not nearly as vigorously. They are easily able to displace hydrogen from acid. a: Write and balance the equation for any of the alkali metals (pick your favorite!) reacting with water to form hydrogen gas and the metal's hydroxide (e.g. sodium hydroxide, potassium hydroxide). (10 points) b: Write and balance the equation for any of the alkaline earth metals (the second column on the left) reacting with hydrochloric acid to form hydrogen gas and the metal's chloride salt (e.g. magnesium chloride, calcium chloride) (10 points)
Answer:
See explanation
Explanation:
In writing a chemical reaction equation, we must ensure that it is balanced. In a balanced chemical reaction equation, the number of atoms of each element on the left hand side of the reaction equation must be equal to the number of atoms of the same atom on the right hand side of the reaction equation.
Let us now consider the reaction of NaOH with water as follows;
2Na(s) + 2H2O(l) ------> 2NaOH(aq) + H2(g)
For the reaction of Magnesium metal and HCl we have;
Mg(s) + 2HCl(aq) -------> MgCl2(aq) + H2(g)
Mg(NO3)2 soluble or insoluble?
Answer:
The chemical compound Mg(NO3)2, also known as magnesium nitrate, is very soluble, especially in water.
3. Explain what would happen to the digestion process if enzymes were not present. SC.6.L.14.5
Please need this ASAP. Calculate the mass of lime, CaO, that would be produced from 250 tonnes of limestone,
CaCO3.
Relative atomic masses: C 12; O 16; Ca 40.
Answer:
1.4×10⁸ g of CaO
Explanation:
We'll begin by converting 250 tonnes to grams (g). This can be obtained as follow:
1 tonne = 1×10⁶ g
Therefore,
250 tonne = 250 × 1×10⁶
250 tonne = 2.5×10⁸ g
Next, the balanced equation for the reaction.
CaCO₃ —> CaO + CO₂
Next, we shall determine the mass of CaCO₃ that decomposed and the mass CaO produced from the balanced equation. This can be obtained as follow:
Molar mass of CaCO₃ = 40 + 12 + (16×3)
= 40 + 12 + 48
= 100 g/mol
Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g
Molar mass of CaO = 40 + 16
= 56 g/mol
Mass of CaO from the balanced equation = 1 × 56 = 56 g
SUMMARY:
From the balanced equation above,
100 g of CaCO₃ decomposed to produce 56 g of CaO.
Finally, we shall determine the mass of CaO produced by the decomposition of 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃. This can be obtained as follow:
From the balanced equation above,
100 g of CaCO₃ decomposed to produce 56 g of CaO.
Therefore, 2.5×10⁸ g of CaCO₃ will decompose to produce =
(2.5×10⁸ × 56)/100 = 1.4×10⁸ g of CaO.
Thus, 1.4×10⁸ g of CaO will be obtained from 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃.
PLZ HELP URGENT!!!!!
Answer:
A fluke because it is an vertebrae
Explanation:
When developing a question for a scientific inquiry, the question will ideally
A.
not just simply ask why.
B.
identify variables.
C.
be measurable.
D.
all of these
Answer: https://brainly.com/question/2426371
Explanation: Someone already answered this, click the link. YW! :))
Scientists often use controlled experiments to answer questions. Choose ALL correct statements about controlled experiments. A) No changes are made to a test group in an experiment. B) A control group is used for comparison to other groups. C) Only one change can be made per test group in an experiment. D) Changes can only be made to the control group in an experiment. E) A controlled experiment must have a control group and test group(s).
Answer:
B) A control group is used for comparison to other groups.
E) A controlled experiment must have a control group and test group(s).
Explanation:
Answer:
B & E should be the answers
You pump 100 gas particles in Basketball A and 100 gas particles in Basketball B. both basketballs are at room temperature ¿Which basketball will be more firm? ¿And Why?
Answer:
I think the answer is probably b
PLEASE ANSWER!! THANK YA!
Using Graham's Law of Effusion, calculate
the approximate time it would take for
1.0 L of argon gas to effuse, if 1.0 L of
oxygen gas took 12.7 minutes to effuse
through the same opening.
Answer:
I think the answer is X
Explanation:
X is a variable and variables stand for the unknown
Whay happens regularly in fission reaction
Answer:
In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process. The fission process also releases extra neutrons, which can then split additional atoms, resulting in a chain reaction that releases a lot of energy.
Explanation:
Hydrofluoric acid and Water react to form fluoride anion and hydronium cation, like this HF(aq) + H_2O(l) rightarrow F(aq) + H_3O^+ (aq) At a certain temperature, a chemist finds that a 5.6 L reaction vessel containing an aqueous solution of hydrofluoric acid, water, fluoride anion, and hydronium cation at equilibrium has the following composition: Calculate the value of the equilibrium constant K_C for this reaction. Round your answer to 2 significant digits. K_C =
Answer:
Kc = 1.09x10⁻⁴
Explanation:
HF = 1.62g
H₂O = 516g
F⁻ = 0.163g
H₃O⁺ = 0.110g
To solve this question we need to find the moles of each reactant in order to solve the molar concentration of each reactan and replacing in the Kc expression. For the reaction, the Kc is:
Kc = [H₃O⁺] [F⁻] / [HF]
Because Kc is defined as the ratio between concentrations of products over reactants powered to its reaction coefficient. Pure liquids as water are not taken into account in Kc expression:
[H₃O⁺] = 0.110g * (1mol /19.01g) = 0.00579moles / 5.6L = 1.03x10⁻³M
[F⁻] = 0.163g * (1mol /19.0g) = 0.00858moles / 5.6L = 1.53x10⁻³M
[HF] = 1.62g * (1mol /20g) = 0.081moles / 5.6L = 0.0145M
Kc = [1.03x10⁻³M] [1.53x10⁻³M] / [0.0145M]
Kc = 1.09x10⁻⁴Scientists have been classifying living organisms for centuries. In the 1970s, organisms were classified in a five-kingdom
classification scheme. However, two decades later, organisms called Archaebacteria were discovered. This led to a three-domain
system of classification that combined some of the previous five-kingdom schemes.
What does this change in classification methods demonstrate?
Answer:
Classification is important because it allows scientists to identify, group, and properly name organisms via a standardized system (Linnaeus Taxonomy); based on similarities found in the organisms DNA/RNA (genetics), Adaptations (Evolution), and Embryonic development (Embryology) to other known organisms to better.
Hope I helped!!
The five kingdoms of classifications were animalia, plant, fungi, protista and monera. Later Archaebacteria was discovered and this led to the 3 kingdom classification animalia, plantae and protista.
What is biological classification?There are different classifications for living things based on their nature, body and origin. The kingdom animalia includes all the animals including human beings.
Kingdom plante includes all the plants and kingdom fungi, protista and monera are of microbes. Later the discovery and study of Archaebacteria proved that they exhibit similar body type and functions as bacterias.
After that, scientists turned into 3 kingdom classification, where all the prokaryotic organisms including protists, monera and fungi classified as one. The evolutional changes originated in them made this classification.
To find more on biological classification, refer here:
https://brainly.com/question/2994982
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What causes a ionic bond to occur
Answer:
when the valence (outermost) electrons of one atom are transferred permanently to another atom
Identify the compound that contains an ionic bond.
*
O
H20
O CO2
O Naci
O CH3CH2OH
Answer:
Nacl compound contain ionic bonds because sodium is metal and chlorin is nonmetal
What rock forms from magma oozing onto the surface?
a. Igneous rock
b. Metamorphic rock
C. Sedimentary rock
d. Lava rock
which is the best explanation for why organisms must meet their needs for resources?
a. So they can have more entertainment.
b. So they can survive and reproduce.
c. So they can continue sleeping all day.
d. So they can swim and fly faster.
Answer:
B
Explanation:
A isnt correct because animals have no emotions
C isnt correct because animals dont sleep all day
D isnt correct because not all organisms can swim or fly
B makes the most sense
help someone i need this
Whoever gets these 2 right gets brainliest! :)
the first one is A covalent bond.
the second one is Answer: B Decomposition
2Fe + 6HCl -> 2FeCl3 + 3H2 If 7.0 moles of HCl is added to enough iron that the HCl is completely used up, how many
moles of hydrogen gas will be produced?
Answer: 3.5 moles of hydrogen gas will be produced.
Explanation:
The balanced chemical equation is:
[tex]2Fe+6HCl\rightarrow 2FeCl_3+3H_2[/tex]
As HCl gets completely used up, [tex]HCl[/tex] is the limiting reagent.
According to stoichiometry :
6 moles of [tex]HCl[/tex] produces = 3 moles of [tex]H_2[/tex]
Thus 7.0 moles of [tex]HCl[/tex] produces=[tex]\frac{3}{6}\times 7.0=3.5moles[/tex] of [tex]H_2[/tex]
Thus 3.5 moles of hydrogen gas will be produced.
whose model was discarded as a result of Rutherford's model?
A Dalton's model
B Thomson's model
C Bohr's model
D Quantum's model
Answer:
A. Dalton's model
Explanation:
Dalton's model was discarded as a result of Rutherford's model.
[tex]{ }[/tex]
[tex]\small\sf\:\:\:\:\:\:\:\:{:}\:\Longrightarrow{\bold{\pink{\sf{Thomson's \:model}}}}[/tex]
Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. In the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) In the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) Calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions.
Answer:
Overall enthalpy change for the formation of one mole nitric acid from nitrogen, hydrogen and oxygen, ΔH = -376 KJ
Note: the question is incomplete. The complete question is given below:
Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. In the first step, nitrogen and hydrogen react to form ammonia: N₂(g) + 3H₂(g) → 2NH₃(g) ΔH = -92. kJ In the second step, ammonia and oxygen react to form nitric acid and water: NH3(g) + 2O2(g) → HNO3(g) + H2O(g) ΔH = -330. kJ Calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. Round your answer to the nearest kJ.
Explanation:
From Hess's law of constant heat summation, the total enthalpy change for a reaction is the sum of all changes without regard to the number of multiple stages or steps involved in a reaction.
Enthalpy is a state function as it does not depend on the path taken to attain its value. Therefore, the summation of the enthalpy changes involved in the individual steps in the reaction of the formation of nitric acid will be equal to the enthalpy change of the overall reaction step.
For the first reaction step:
N₂(g) + 3H₂(g) → 2NH₃(g) ΔH = -92. kJ
For the second reaction step:
NH₃(g) + 2O₂(g) → HNO3(g) + H2O(g) ΔH = -330. kJ
Overall reaction step:
[tex]\frac{1}{2}[/tex]N₂(g) + [tex]\frac{3}{2}[/tex]H₂(g) + 2O₂(g) → HNO₃ + H₂O ΔH = ?
The overall reaction for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen shows that the first reaction step should be divided by 2
[tex]\frac{1}{2}[/tex]N₂(g) + [tex]\frac{3}{2}[/tex]3H₂(g) → NH₃(g) ΔH = -46. kJ
Overall enthalpy change, ΔH = ΔH₁ + ΔH₂
Overall enthalpy change,ΔH = (-46 KJ) + (-330 KJ)
Overall enthalpy change,ΔH = -376 KJ
Rocks are classified as sedimentary, metamorphic, or igneous on the basis of
the
a. age of the rocks.
b. way the rocks were formed.
c. types of fossils the rocks contain.
d. number of minerals found in the rocks.
mathdrrggeszdrsz seer r-
Answer:
130!!
Explanation:
State the coefficient required to correctly balance the following chemical equation:
_____ Ca3(PO4)2+ _____ NaCl ---------> _____ Na3PO4 + _____ CaCl2
Answer:
1 Ca3(PO4)2+ 6 NaCl ---------> 2 Na3PO4 + 3 CaCl2
Oxidation-reduction (redox) reactions are reactions:______
a) in which oxidation numbers change.
b) Oxidation numbers are either real charges or formal charges which help chemists keep track of electron transfer.
c) In practice, oxidation numbers are best viewed as a bookkeeping device.
d) Oxidation cannot occur without reduction.
e) In a redox reaction the substance which is oxidized contains atoms which increase in oxidation number.
f) Oxidation is associated with electron loss (helpful mnemonic: LEO
Answer:
A. in which oxidation numbers change
Explanation:
This is because in oxidation reduction reactions or redox reactions, involves the sharing or transfer of electrons between species and the oxidation numbers changes. There is change in electrons, ions or oxidation number by gaining or lossing electrons. Increase in oxidation number is an indication of oxidation while decrease in oxidation indicate reduction.
What is chemistry
What is the bond type in CaO
Answer:
Ionic bond
CaO is an ionic bond. Two-element compounds are usually ionic when one element is a metal and the other is a non-metal. It is made up of one metal ion/cation(Ca^2+) and an non-metal ion/anion(O^2-).