Answer:
a. pH = 2.04
b. pH = 3.85
c. pH = 8.06
d. pH = 11.56
Explanation:
The nitrous acid is a weak acid (Ka = 5.6x10⁻⁴) that reacts with NaOH as follows:
HNO₂ + NaOH → NaNO₂(aq) + H₂O(l)
a. At the beginning there is just a solution of 0.12M HNO₂. As Ka is:
Ka = [H⁺] [NO₂⁻] / [HNO₂]
Where [H⁺] and [NO₂⁻] ions comes from the same equilibrium ([H⁺] = [NO₂⁻] = X):
5.6x10⁻⁴ = X² / 0.15M
8.4x10⁻⁵ = X²
X = [H⁺] = 9.165x10⁻³M
As pH = -log [H⁺]
pH = 2.04b. At this point we have HNO₂ and NaNO₂ (The weak acid and the conjugate base), a buffer. The pH of a buffer is obtained using H-H equation:
pH = pKa + log [NaNO₂] / [HNO₂]
Where pH is the pH of the buffer,
pKa is -log Ka = 3.25
And [NaNO₂] [HNO₂] could be taken as the moles of each compound.
The initial moles of HNO₂ are:
0.100L * (0.15mol / L) = 0.015moles
The moles of base added are:
0.0800L * (0.15mol / L) = 0.012moles
The moles of base added = Moles of NaNO₂ produced = 0.012moles.
And the moles of HNO₂ that remains are:
0.015moles - 0.012moles = 0.003moles
Replacing in H-H equation:
pH = 3.25 + log [0.012moles] / [0.003moles]
pH = 3.85c. At equivalence point all HNO2 reacts producing NaNO₂. The volume added of NaOH must be 100mL. That means the concentration of the NaNO₂ is:
0.15M / 2 = 0.075M
The NaNO₂ is in equilibrium with water as follows:
NaNO₂(aq) + H₂O(l) ⇄ HNO₂(aq) + OH⁻(aq) + Na⁺
The equilibrium constant, kb, is:
Kb = Kw/Ka = 1x10⁻¹⁴ / 5.6x10⁻⁴ = 1.79x10⁻¹¹ = [OH⁻] [HNO₂] / [NaNO₂]
Where [OH⁻] = [HNO₂] = x
[NaNO₂] = 0.075M
1.79x10⁻¹¹ = [X] [X] / [0.075M]
1.34x10⁻¹² = X²
X = 1.16x10⁻⁶M = [OH⁻]
pOH = -log [OH-] = 5.94
pH = 14-pOH
pH = 8.06d. At this point, 5mL of NaOH are added in excess, the moles are:
5mL = 5x10⁻³L * (0.15mol / L) =7.5x10⁻⁴moles NaOH
In 100mL + 105mL = 205mL = 0.205L. [NaOH] = 7.5x10⁻⁴moles NaOH / 0.205L =
3.66x10⁻³M = [OH⁻]
pOH = 2.44
pH = 14 - pOH
pH = 11.56how does fracked gas and oil impact the availability of oil and gas in the US
Question 13 of 25
A scientist measures how quickly bamboo plants grow after receiving
different amounts of water. She gives each plant a different amount of water
and measures the plant's growth. What is the manipulated variable in this
experiment?
A. The total number of bamboo plants
B. The number of days of the experiment
C. The size of the bamboo plant
D. The amount of water given
Quinine in a 1.664-g antimalarial tablet was dissolved in sufficient 0.10 M to give 500 mL of solution. A 15.00-mL aliquot was then diluted to 100.0 mL with the acid. The fluorescence intensity for the diluted sample at 347.5 nm provided a reading of 327 on an arbitrary scale. A standard 100 ppm quinine solution registered 180 when measured under conditions identical to those for the diluted sample. Calculate the mass of quinine in milligrams in the tablet.
Answer:
605.6mg of quinine
Explanation:
Based on Lambert-Beer's law, the intensity of an optical measurement is directely proportional to its concentration.
Unknown concentration gives a reading of 327
100 ppm gives 180 of intensity
The concentration of the diluted quinine tablet is:
327 * (100ppm / 180) = 181.67 ppm. The final dilution
The concentration of the first diluted solution is:
181.67 ppm * (100.0mL / 15mL) = 1211ppm
ppm could be defined as mass of solute (In this case of quinine) in mg per liter of solution. That is:
1211mg / L
As the tablet was diluted to 500mL = 0.5L, the mass of the quinine is:
0.5L * (1211mg / L) =
605.6mg of quinineJoaquin's doctor tested Joaquin's reflexes by tapping his knee. The doctor
explained to Joaquin that the tapping sends a signal to his spinal cord. The
spinal cord then sends a signal to the muscle in Joaquin's thigh, and his leg
moves. Which of the following body systems is involved in this process?
A. Respiratory system
B. Nervous system
C. Skeletal system
D. Digestive system
Answer: Skeletal System
Explanation: Sense It's Sending up a signal up Joaquin's spinel cord It must be traveling threw his skeletal system
Answer:
its the nervous system because by tapping the knee, it will send a nerve down the neuron, through the mylein sheath and through the axon terminals to the receptors, which will recieve the nerve's signal and send it to the brain through the spinal cord in simple terms.
A 0.530 M Ca(OH)2 solution was prepared by dissolving 36.0 grams of Ca(OH)2 in enough water. What is the total volume of the solution thus formed? (4 points)
Answer:
0.917 L
Explanation:
Step 1: Given data
Molar concentration of the solution (M): 0.530 M (0.530 mol/L)Mass of Ca(OH)₂ (solute): 36.0 gStep 2: Calculate the moles corresponding to 36.0 g of Ca(OH)₂
The molar mass of Ca(OH)₂ is 74.09 g/mol.
36.0 g × 1 mol/74.09 g = 0.486 mol
Step 3: Calculate the volume of the solution
Molarity is equal to the moles of solute divided by the liters of solution.
M = moles of solute / liters of solution
liters of solution = moles of solute / M
liters of solution = 0.486 mol / (0.530 mol/L) = 0.917 L
Answer:
0.917 liters
Hope this helps! :D
Explanation:
5.
(08.02 MC)
A 0.530 M Ca(OH)2 solution was prepared by dissolving 36.0 grams of Ca(OH)2 in enough water. What is the total volume of the solution thus formed? (4 points)
An exothermic reaction
In an endothermic reaction, the energy of the products is
the energy of the reactants.
Activation energy is
the potential energy of the products.
Answer:
An exothermic reaction
✔ produces energy
.
In an endothermic reaction, the energy of the products is
✔ more than
the energy of the reactants.
Activation energy is
✔ always greater than
the potential energy of the products
Answer:
Produces energy
More than
Always greater than
Explanation:
Glucose can be consumed for energy in three ways one ends with glucose being converted into CO2,
another way it is converted into lactic acid/actate, and the third way ends with ethanol. We humans use
the first two ways. What do we call each of the three ways? When/why would we use each of the first
two ways, and why not the third way?
Answer:
In humans, there are two major processes used to convert glucose into energy. cellular respiration or aerobic respiration is one of these processes that take place in presence of oxygen that converts glucose into CO2.
The other process is lactic acid fermentation occurs in muscles in case of depletion of oxygen which converts glucose into lactic acid.
The third process is alcoholic fermentation does not take place in humans and occurs in yeast and some bacteria where they produce ethanol.
Humans cannot use alcoholic fermentation in their own body ferment as there is no genetic information in us to do so as it has encoded in yeast and bacteria.
Can someone please help with this !!!!
Which product will precipitate in the following reaction:
CaCl2 + Na2CrO4 → CaCrO4 + 2 NaCl
A.NaCl
B.CaCrO4
C.Na2CrO4
D.CaCl2
Answer:
a
Explanation:
PLEASE HELP ME PLEASEEE AND QUICK.
NO TROLL ACCOUNT AND POSTING A LINK TO NO WHERE, PLEASE. DONT. UR WASTING MY TIME.
SOMEONE PLEASE BE NICE.
Please answer ALL THREE if u can, thank you so so so so much!!!
Answer:
Eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
Explanation:
3.
The color of the powdered form of a mineral is called
O fracture
O cleavage
O luster
O streak
Answer:
D. Streak.
Explanation:
A mineral, in simple terms, can be defined as a solid inorganic substance that occurs in a pure form with a specific crystal structure. A mineral is identified based on its physical properties which include luster, color, streak, crystal shape, etc.
The color of the powdered form of a mineral is called a streak. A streak is a useful property in distinguishing sulfide and oxide minerals. To check the color of a mineral, it is rubbed against the surface of a ceramic streak plate or a piece of unglazed ceramic. In its finely powdered form, a mineral is easy to identify.
Therefore, option D is correct.
a shape with five sides is called a?
Answer:
A five-sided shape is called a pentagon.
Explanation:
Answered by NONE other than the ONE & ONLY #QUEEN herself aka #DRIPPQUEENMO!!!
Hope this helped!!!
Answer:
a pentagon
Explanation:
I remember that a pentagon has 5 sides
811.68 J of energy are used on a 95g chunk of unknown metal. Calculate the resulting temperature change if the specific heat of the metal is 0.534 J/g*C. oC
Answer:
16 °C
Explanation:
Step 1: Given data
Provided heat (Q): 811.68 JMass of the metal (m): 95 gSpecific heat capacity of the metal (c): 0.534 J/g.°CStep 2: Calculate the temperature change (ΔT) experienced by the metal
We will use the following expression.
Q = c × m × ΔT
ΔT = Q/c × m
ΔT = 811.68 J/(0.534 J/g.°C) × 95 g = 16 °C
The bonds present in carbon tetrachloride (CCI) are
A. covalent
B.ionic
C. metallic
D. van der Waals
If 3.644 g (78.01 g/mol) is dissolved in 42.054 g of water and the temperature goes
from 27.8°C to 36.2°C, what is the molar Hrxn (kJ/mol)? Assume the solution has s
= 4.18 Hint: what is the mass of the entire solution?
g.°C
Answer:
[tex]H_{rxn}=-34.36\frac{kJ}{mol}[/tex]
Explanation:
Hello there!
In this case, according to the given information, it is possible to realize that the heat released by the reaction is used up to heat up the mixture, which means we can write:
[tex]-Q_{rxn}=Q_{sol}[/tex]
Whereas the Q of solution is given by the total mass (3.644+42.054), the specific heat of the solution and the change in temperature; thus, we obtain:
[tex]-Q_{rxn}=(3.644g+42.054g)*4.18\frac{J}{g\°C}*(36.2\°C-27.8\°C)\\\\ Q_{rxn}=-1604.55J[/tex]
Next, by computing the moles of the solute, we can proceed to compute the kJ/mol for the enthalpy of reaction (dissolution):
[tex]n=\frac{3.644g}{78.01g/mol}=0.0467mol\\\\H_{rxn}=\frac{Q_{rxn}}{n}\\\\ H_{rxn}=\frac{-1604.55J}{0.0467mol}*\frac{1kJ}{1000J}\\\\ H_{rxn}=-34.36\frac{kJ}{mol}[/tex]
Best regards!
what evidence Have you collected to explain The relationship between the seafloor Ready mid ocean ridges and ocean trenches
Answer:Abundant evidence supports the major contentions of the seafloor-spreading theory. First, samples of the deep ocean floor show that basaltic oceanic crust and overlying sediment become progressively younger as the mid-ocean ridge is approached, and the sediment cover is thinner near the ridge.
Explanation:
Name 3 ways you can keep our community healthy?
Answer:
1. Practice healthy habits with kids in your life. ...
2. Engage in your school's efforts to encourage healthy practices. ...
3. Learn more about the decisions local officials are making that impact your environment. ...
4. Give back healthy options to your community.
Explanation:
The atomic musses of N (99. 64 percent) and 1N (0.36 percent) are 14.00307 amu and 15.0001 amu, respectively. Calculate the average atomic mass of nitrogen. The percentages in parentheses denote the relative abundances C01?
Answer:
14.01 amu
Explanation:
Step 1: Given data
Isotope Atomic mass (am) Abundance (ab)
¹⁴N 14.00307 amu 99.64% (0.9964)
¹⁵N 15.0001 amu 0.36% (0.0036)
Step 2: Calculate the average atomic mass (aam) of nitrogen
We will use the following expression.
aam = ∑ am × ab
aam = 14.00307 amu × 0.9964 + 15.0001 amu × 0.0036 = 14.01 amu
How many moles of NaCl are contained in 50.0 mL of 2.50 M NaCl?
Answer: 0.144 moles. :)
Explanation:
The number of moles of NaCl that are contained in 50.0 mL of 2.50 M NaCl is 0.125 moles
Using this formula
Molarity=Moles of solute/Liters of solution
First step is to convert 50.0 mL to Liters
Litres=50.0 ml×1 L/1000 ml
Litres=0.05 L
Now let determie the number of moles of NaCl
2.50M=moles/0.05
moles=2.50M(0.05)
moles = 0.125 moles of NaCl
Inconclusion The number of moles of NaCl that are contained in 50.0 mL of 2.50 M NaCl is 0.125 moles
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A compound with an approximate molar mass of
65.0g/mol is made up of C, H and Cl. This same
Compound contains 55% of Cl by mass .lf 9g
of the compound contains 4.19 x 10²³ atoms,
determine the compound's:
a empirical formular and molecular formular
Reaction intermediates differ from activated complexes in that A. they are stable molecules with normal bonds and are frequently isolated. B. they are molecules with normal bonds rather than partial bonds and can occasionally be isolated. C. they are intermediate structures which have characteristics of both reactants and products. D. they are unstable and can never be isolated. E. all reactions involve reaction intermediates, but not all have activated complexes.
Answer:
they are molecules with normal bonds rather than partial bonds and can occasionally be isolated.
Explanation:
In chemistry, reaction intermediates are species that are formed from reactants and are subsequently being transformed into products as the reaction progresses. In other words, reaction intermediates are species that do not appear in a balanced reaction equation but occur somewhere along the reaction mechanism of a non-elementary reaction. They are usually short lived species that possess a high amount of energy. They may or may not be isolated.
They are often molecular species with normal bonds unlike activated complexes that are sometimes hypervalent species.
What is the molarity (molar concentration, unit = M) of K+ found in 200 mL 0.2 M K2HPO4 solution?
Answer:
0.4 M
Explanation:
The process that takes place in an aqueous K₂HPO₄ solution is:
K₂HPO₄ → 2K⁺ + HPO₄⁻²First we calculate how many K₂HPO₄ moles are there in 200 mL of a 0.2 M solution:
200 mL * 0.2 M = 40 mmol K₂HPO₄Then we convert K₂HPO₄ moles into K⁺ moles, using the stoichiometric coefficients of the reaction above:
40 mmol K₂HPO₄ * [tex]\frac{2mmolK^+}{1mmolK_2HPO_4}[/tex] = 80 mmol K⁺Finally we divide the number of K⁺ moles by the volume, to calculate the molarity:
80 mmol K⁺ / 200 mL = 0.4 MWhich compound contains a bond with the least ionic character? A. CO B. CaO C. K2O D. Li2O
Answer:
A. CO
Explanation:
This is the answer I believe based on that it has the least amount of elements leading me to think that it would have the least ionic character.
The compound that contains a bond with the least ionic character is CO.
Ionic bonding involves transfer of valency electrons. Usually from a metal to a non metal.
The ionic character or nature of a bond is determined by the relative
electronegativity of the atoms involved.
So, the bigger the difference between the electronegativity of two atoms, the more likely it is to be ionic.
This simply implies that if the electronegativity differences of the atoms
involved are smaller, the ionic character will be small.
Therefore, the compound that contain a bond with the least ionic character is CO.
The difference in negativity of the carbon and oxygen atoms are small, this is
why the compound CO among the options possess the least ionic character.
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The oxidation state for Cl is A. -1 as a reactant and +1 as a product B. -1 as a reactant and 0 as a product C. -1 as a reactant and -1 as a product D. +1 as a reactant and +1 as a product
Answer:
no sure
Explanation:
If aqueous solutions of Ba(OH)2 and HNO3 are mixed, what products are formed? Select one: a. BaN2(s) + H2O(l) b. Ba(NO3)2(aq) + H2O(l) c. Ba(s) + H2(g) + NO2(g) d. Ba2O(s) + NO2(g) + H2O(l) e. Ba3N2(s) + H2O(l)
Answer: Ba(NO3)2(aq) + H2O(l)
Explanation:
2n2+5O2 = 2N2O5 what mass of nitrogen is required to react with 16 grams of oxygen
Answer:
Explanation:
5.6
According to the stoichiometry of the given chemical equation, 11.2 grams of nitrogen is required to react with 16 grams of oxygen.
What is chemical equation?Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
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How do humans influence genetic outcomes in artificial selection and what impacts does this have on society?
Answer:
In artificial selection, humans have the capacity to influence certain characteristics of organisms by selective breeding. One can choose desired parental traits determined by genes, which are then passed on to offspring.
SO2 + PCL5 → SOCL2 + POCL3
What mass of SOCL2 is produced when 1.35 g SO2 react with 2.75 g PCL5
Answer:
2.34
Explanation:
Water pollution has severely impacted animals and plants in New York's Hudson
Pure substance uniform