Answer:
The pH does not decrease drastically because the HCl reacts with the sodium azide (NaN₃) present in the buffer solution.
Explanation:
The buffer solution is formed by 0.26 moles of the weak acid, hydrazoic acid (HN₃), and by 0.26 moles of sodium azide (NaN₃). The equilibrium reaction of this buffer solution is the following:
HN₃(aq) + H₂O(l) ⇄ N₃⁻(aq) + H₃O⁺(aq)
The pH of this solution is:
[tex] pH = pka + log(\frac{[N_{3}^{-}]}{[HN_{3}]}) = -log(2.5 \cdot 10^{-5}) + log(\frac{0.26 mol/1 L}{0.26 mol/1 L}) = 4.60 [/tex]
When 0.05 moles of HCl is added to the buffer solution, the following reaction takes place:
H₃O⁺(aq) + N₃⁻(aq) ⇄ HN₃(aq) + H₂O(l)
The number of moles of NaN₃ after the reaction with HCl is:
[tex] \eta_{NaN_{3}} = \eta_{i} - \eta_{HCl} = 0.26 moles - 0.05 moles = 0.21 moles [/tex]
Now, the number of moles of HN₃ is:
[tex] \eta_{HN_{3}} = \eta_{i} + \eta_{HCl} = 0.26 moles + 0.05 moles = 0.31 moles [/tex]
Then, the pH of the buffer solution after the addition of HCl is:
[tex] pH = pka + log(\frac{[N_{3}^{-}]}{[HN_{3}]}) = -log(2.5 \cdot 10^{-5}) + log(\frac{0.21 mol/V_{T}}{0.31 mol/V_{T}}) = 4.43 [/tex]
The pH of the buffer solution does not decrease drastically, it is 4.60 before the addition of HCl and 4.43 after the addition of HCl.
Therefore, the pH does not decrease drastically because the HCl reacts with the sodium azide (NaN₃) present in the buffer solution.
I hope it helps you!
how does an organic pH indicator works. (illustrate using chemical equations and
mathematical expressions
Answer:
A pH indicator is a halochromic chemical compound added in small amounts to a solution so the pH (acidity or basicity) of the solution can be determined visually. Hence, a pH indicator is a chemical detector for hydronium ions (H3O+) or hydrogen ions (H+) in the Arrhenius model.A pH of 7 indicates a neutral solution like water. A pH less than 7 indicates an acidic solution and a pH greater than 7 indicates a basic solution. Ultimately, the pH value indicates how much H+ has dissociated from molecules within a solution. The lower the pH value, the higher concentration of H+ ions in the solution and the stronger the acid. Likewise, the higher the pH value, the lower the concentration of H+ ions in the solution and the weaker the acid.
Explanation:
state the purpose of respiration.
Answer:
The purpose of respiration is to supply the body with oxygen and eliminate carbon dioxide. Oxygen is essential for cellular respiration as cells cannot exist in the absence of it. The human lungs are the organs responsible for respiration.
Explanation:
Respiration refers to a person’s breathing and the movement of air into and out of the lungs. The respiratory system provides oxygen to body tissues for cellular respiration, removes the waste product carbon dioxide, and helps maintain acid–base balance. Inspiration is the process that causes air to enter the lungs, and expiration is the process that causes air to leave the lungs . A respiratory cycle (or one breath while you are measuring respiratory rate) is one sequence of inspiration and expiration.
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)
In the second step, ammonia and oxygen react to form nitric acid and water:
NH3(g)+ 2O2(g) → HNO3(g) + H2O(g)
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 .
Answer:
-376 kJ.
Explanation:
A proton is a hydrogen atom without its electron?
True
False
Why are white Americans less affected by toxic waste and air pollution than people of color?
A.They tend to live in urban centers .
B. They tend to vote in smaller numbers compared to other groups.
C. They tend to have more of a say in where uncontrolled toxic waste sites are located.
D. All of the above are true.
Answer:
D. All the above
Explanation:
WHite people are "previlged"
The chart below describes the molecular motion in solids, liquids, gases, and plasma.
Solids Liquids Gases Plasma
slower than liquids, slower than solids but faster than solids faster than solids,
gases, and plasma faster than gases and but slower than liquids and gases
plasma plasma
The information in the chart about molecular motion is incorrect for:______
1. solids
2. liquids
3. gases
4. plasma
Answer:
Liquids
Note: the attachment below shows the properly arranged chart
Explanation:
The order of molecular motion of matter from fastest to slowest is;
Plasma>Gases>Liquids>Solids
Liquids move faster than solids not slower.
Answer:
liguids
Explanation:
A substance is followed by the symbol (1) in a chemical equation. What does the symbol represent?
Answer:
The symbol (l) stands for liquid phase.
Explanation:
If 100 ml of a 0.75 m hno3 is required to exactly neutralize 50 ml of naoh what is the concentration of the base?
Answer:
1.5M
Explanation:
M1V1=M2V2
(0.75M)(100ml)=(M2)(50 ml)
M2= 1.5 M
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The decomposition of nitrogen dioxide is described by the following chemical equation:
2NO_2 (g) --------> 2NO (g) + O_2 (g)
Suppose a two-step mechanism is proposed for this reaction, beginning with this elementary reaction:
NO_2 (g) --------> NO_(g) + O_(g)
Suppose also that the second step of the mechanism should be bimolecular.
a) Suggest a reasonable second step. That is, write the balanced chemical equation of a bimolecular elementary reaction that would complete the proposed mechanism.
Answer:
The balanced chemical equation will be "[tex]NO_{2}+O\rightarrow NO+O_{2}[/tex]".
Explanation:
The given equation is:
[tex]2NO_{2}\rightarrow 2NO+O_{2}[/tex]
Step 1:
[tex]2NO_{2}\rightarrow NO+O[/tex]...(equation 1)
Step 2:
[tex]NO_{2}+O\rightarrow NO+O_{2}[/tex]...(equation 2)
On adding "equation 1" and "equation 2", we get
⇒ [tex]NO_{2}+NO_{2}+O\rightarrow NO+O+NO+O_{2}[/tex]
⇒ [tex]2NO_{2}\rightarrow 2NO+O_{2}[/tex]
The second step:
⇒ [tex]NO_{2}+O\rightarrow NO+O_{2}[/tex]
What do you need in order to do a stoichiometric calculation? (Choose
multiple)
Balanced Chemical Equation
Molar masses of compounds involved
The type of reaction taking place
Oxidation Numbers
Imagine designing an experiment in which the presence of a gas is determined by simply listening to the gas with your ear. The human ear can detect pressures as low as 2 x 10^-5 N*m^-2. Assuming that the eardrum has an area of roughly 1 mm^2, what is the minimum collisional rate that can be detected by ear? Assume that the gas of interest is N2 at 298 K.
Answer:
Explanation:
Pressure = Force/Area
so,
Force =Pressure x Area
Force =(2x 10⁻⁵ )N/M² x (1 x (10⁻³)² M²
Force = 2 x 10⁻¹¹N
as we know,
Force= mass x acceleration ( F=m.a)
a = F/m
a =(2 x 10⁻¹¹N)/28
g since 1 N=1.kg.m.s⁻²
a=(2 x 10-11kg.m.s⁻² )/(28 x 10⁻³kg)
a = 5.6 x 10-7 m.s⁻²
thus minimum collision rate that can be detected is 5.6 x 10-7 m.s⁻²What is the amount of energy needed to heat 2.3 g of aluminum from 6.2oC to 46.9oC in Joules?
Answer:
Heat required = 84.25 Joule
Explanation:
Heat required = mass × specific heat capacity × temperature change
Specific heat capacity of aluminium = 0.90 J/g/K
Heat required = 2.3 × 0.9 × (46.9 -6.2)
= 84.25 Joules
what is the sex-ratio in rajasthan according to 2011 census?
Answer:
Sex ratio of India according 2011 census is 940 females per 1000 males. Sex ratio of Rajasthan is 928 which means there are 928 female present per 1000 males
Explanation:
pls check my answer brain list
Use one of your experimentally determined values of k, the activation energy you determined, and the Arrhenius equation to calculate the value of the rate constant at 25 °C. Alternatively, you can simply extrapolate the straight-line plot of ln(k) vs. 1/T in your notebook to 1/298, read off the value of ln(k), and determine the value of k. Please put your answer in scientific notation. slope=-12070, Ea=100kJ/mol, k= 0.000717 (45 °C), 0.00284 (55 °C), 0.00492 (65 °C), 0.0165 (75 °C), 0.0396 (85 °C).
Answer:
Explanation:
Use one of your experimentally determined values of k, the activation energy you determined, and the Arrhenius equation to calculate the value of the rate constant at 25 °C. Alternatively, you can simply extrapolate the straight line plot of ln(k) vs. 1/T in your notebook to 1/298 , read off the value of ln(k), and determine the value of k. Please put your answer in scientific notation. slope=-12070, Ea=100kJ/mol, k= 0.000717(45C), 0.00284(55C), 0.00492(65C), 0.0165(75C), 0.0396(85C)
Explanation;
According to Arrhenius equation:
i.e. ln(k2/k1) = -Ea/R (1/T2 - 1/T1)
Where, k1 = 0.000717, T1 = 45 oC = (45+273) K = 318 K
T2 = 25 oC = (25 + 273) K = 298 K
i.e. ln(k2/0.000717) = -12070 (1/298 - 1/318)
i.e. ln(k2/0.000717) = -2.54738
i.e. k2/0.000717 = [tex]e^{-2.54738}[/tex]
= 0.078286
Therefore, the required constant (k2) = 0.078286 * 0.000717 = [tex]5.61*10^-^5[/tex]
the _ is responsible for absorbing the most uv radiation
a chemical reaction can be represented by
Answer:
A chemical reaction is a rearrangement of atoms which turn one or more compounds into new compounds. Equations and models may describe all of the chemical reactions. ... If atoms detach from each other and recombine into various types of atoms, we conclude that there has been a chemical reaction.
Answer:
equations and models.
Explanation:
All chemical reactions can be represented by equations and models.
If it's a summer day and you want to take a picnic are you concerned with weather
or climate? Why?
Answer:
Not really, the chances you will get hurt are insignificant
Explanation:
If you want to produce 11 moles of NH3, how much H2 do you need?
Answer:
33 g of H2
Explanation:
N2 + 3 H2 -> 2 NH3
3 mol H2 -> 2 mol NH3
x -> 11 mol NH3
x= (11 mol NH3 * 3 mol H2)/ 2 mol NH3
x= 16.5 mol H2
1 mol H2 -> 2 g
16.5 mol H2 ->x
x= (16.5 mol H2 * 2 g)/ 1 mol H2
x= 33 g
Three examples of chemical reactions ????? PLEASE HELP
Answer:
Photosynthesis, Respiration, Combustion, Anaerobic Respiration
Explanation:
Im not 100% sure if this is what you are looking for but it should be correct. Hope this helps! :)
Ultraviolet photoelectron spectroscopy (UPS) is an important analytical tool used to characterize the composition of materials in academic, industrial and national laboratories. The technique relies on the photoelectric effect where-in electrons are emitted from a material when it absorbs ultraviolet photons. Make a plot of the kinetic energy of the photo-emitted electrons versus the frequency of the incident light as the frequency is varied across the transition where photon energy exceeds the ionization energy (IE) of a material being examined by UPS. Label you axes.
Answer:
The equation for the Kinetic Energy, [tex]KE_e[/tex], of the photo-emitted electrons is given as follows;
[tex]KE_e = h\cdot f- BE[/tex]
Please find attached the required plot of the kinetic energy versus the frequency
Explanation:
The equation for the Kinetic Energy, [tex]KE_e[/tex], of the photo-emitted electrons is given as follows;
[tex]KE_e = h\cdot f- BE[/tex]
Where:
h = Planck's constant = 6.63×10⁻³⁴ J·s
f = Frequency
BE = Binding Energy = 2.71 eV for Calcium metal
f₀ = Threshold frequency for the material
The ionization energy is the energy required to free an electron from an isolated atom
Which of the following is an example of acceleration? 88m/s, 15km/hr,14m/s East, 9.8 m/s^2 south
Answer: The answer is 9.8 m/s^2 south
Explanation:
Predict the products of the following reactions (assume complete reaction). In your submission include the overall balanced equation, and balanced net ionic equation if applicable:
a. Adding zinc metal to a solution of copper(II) sulfate
b. Dripping silver perchlorate into a solution of sodium carbonate
c. A lump of aluminum metal is dropped into concentrated hydroiodic acid
d. Sucrose is fermented in water by yeast to make ethanol and carbon dioxide (note: water is a reactant)
e. Solid calcium oxide is added to water (careful)
f. A lump of potassium metal is dropped into water (careful)
Answer:
Zn(s) + CuSO4(aq) -----> ZnSO4(aq) + Cu(s)
Na2CO3 (aq)+ 2AgClO4(aq) → 2NaClO4(aq) + Ag2CO3(s)
2Al(s) + 6HI(aq) ------> 2AlI3(aq) + 3H2(g)
C12H22O11(s)+H2O(l)→4C2H5OH(aq)+4CO2(g)
2K(s) + 2H2O(l) ------->2KOH(aq) + H2(g)
Explanation:
In the first reaction, zinc displaces copper from an aqueous copper II salt since zinc is higher than copper in the electrochemical series.
Reaction two leads to the precipitation of silver carbonate. Remember that carbonates are mostly insoluble in water.
Acids are known to displace hydrogen gas from dilute acids. Hence in the third reaction, aluminum displaced hydrogen from aqueous hydroiodic acid.
In the fourth reaction, the action of yeast leads to the fermentation of sucrose yielding ethanol and carbon dioxide in the process.
Metals are known to form aqueous alkaline solutions liberating hydrogen gas when they react with water. Hence potassium metal reacts with water to liberate hydrogen gas and form alkaline potassium hydroxide.
1. What is the answer to the following expression in the correct number of significant figures?
(0.1245) x (0.00003) x (298,000)/(2.0 - 1.5)
Answer:
2 with 1 SF
Explanation:
Which multimedia does this ad from the Centers for Disease Control’s advertising campaign for the flu vaccine include? (more than one)
A.) animation
B.) image
C.) text
D.) graph
E.) chart
Answer:
Image and text
Explanation:
on edge
which of the following is larger then the atomic radius of phosphorus
Options
a: the ionic radius of phosphorus
b: the atomic radius of argon
c: the atomic radius of nitrogen
d: the ionic radius of chlorine
Answer:
a)the ionic radius of phosphorus
Explanation:
phosphorus=2.8.6
for phosphorus to become stable(2.8.8) it gains two electrons thus the ionic radious increases bcz of the gained electrons
which of the following can cause acid precipitation
the use of solar panels
the use of hydroelectricity
the use of coal
all of the above
Answer:
C. The use of coal
Explanation:
Answer:
C. The use of coal
Explanation:
Edge 2021
Plants need sunlight, water, and minerals from the soil in order to grow and thrive. These factors
A.
are always abundant, allowing unlimited growth.
B.
limit the number of plant populations that can grow in an ecosystem.
C.
require human intervention to be replenished.
D.
prevent new plant populations from entering the ecosystem.
Answer:
B. limit the number of plant populations that can grow an ecosystem
Answer:
B. limit the number of plant populations that can grow in an ecosystem.
Explanation:
what is 2H2O state of matter
Answer:
2 MOLECULES OF WATER
Explanation:
SO, LIQUID
I really need to pass chem, someone please help me! <3
5. Which of the following is NOT a physical change?
nailing together boards of wood
breaking an egg
dying your hair
adding food coloring to water