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:
\( pH = pka + log(\frac{[N_{3}^{-}]}{[HN_{3}]}) = -log(2.5 \cdot 10^{-5}) + log(\frac{0.26 mol/1 L}{0.26 mol/1 L}) = 4.60 \)
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:
\( \eta_{NaN_{3}} = \eta_{i} - \eta_{HCl} = 0.26 moles - 0.05 moles = 0.21 moles \)
Now, the number of moles of HN₃ is:
\( \eta_{HN_{3}} = \eta_{i} + \eta_{HCl} = 0.26 moles + 0.05 moles = 0.31 moles \)
Then, the pH of the buffer solution after the addition of HCl is:
\( pH = pka + log(\frac{[N_{3}^{-}]}{[HN_{3}]}) = -log(2.5 \cdot 10^{-5}) + log(\frac{0.21 mol/V_{T}}{0.31 mol/V_{T}}) = 4.43 \)
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!
3) A car traveling at a constant velocity of 35 km/h North comes to a full stop 15 seconds
after the driver applies the brakes. What is the acceleration of the car?
A. 2.3 m/s 2
B. -2.3 m/s 2
C. -0.43 m/s 2
D. 0.43 m/s 2
The acceleration of the car is -2.3m/s².
Explain what an acceleration is.Acceleration is the rate at which the direction and speed of motion change over time. It is said to have been accelerated when something changes its direction and moves faster or slower. Motion on a circle accelerates even when the speed is constant because the direction is constantly changing.
Velocity is the rate at which displacement changes. The rate at which speed changes is known as acceleration. Because it consists of both magnitude and direction, velocity is a vector quantity. Since acceleration is merely the rate at which velocity changes, it too is a vector quantity.
v = u +at
0 = 35 + a×15
15a = -35
a = -35/15
a = -2.3m/s².
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Answer:
B. -2.3 m/s²
Explanation:
To answer this question, we have to use the following formula:
\(\boxed{a = \frac{v - u}{t}}\),
where:
• a ⇒ acceleration
• v ⇒ final velocity
• u ⇒ initial velocity
• t ⇒ time taken for the change in velocity to occur
From the question, we know that initially, the car was travelling at 35 km/h. Therefore, u = 35 km/h. The question also tells us that the car comes to a full stop, meaning its final velocity is 0 m/s. Therefore, v = 0 km/h. It takes the car 15 seconds to stop, so t = 15 s.
Using the information above and substituting it into the formula, we can calculate the acceleration of the car:
\(a = \frac{0 - 35}{15}\)
= -2.3 m/s²
Therefore, the acceleration of the car is -2.3 m/s², and the correct answer is B.
Use logarithmic properties to solve the following equation log3 5x+ log3 7= 4 leave your answer in fraction form please
Explanation:
Adding logs of same base is equivalent to multiplying the arguments. You get:
\( log_{3}(35x) = 4\)
Use the definition of the log to turn this into an exponential function:
\( {3}^{4} = 35x\)
\(81 = 35x\)
\(x = \frac{81}{35} \)
What is the concentration (molarity) of a solution of NaCl if 350. mL of a 2.5 M NaCl solution is diluted to a total volume of 5.0 mL? (NEED HELP ASAP)
The concentration (molarity) of the final NaCl solution is 175 M.
To find the concentration (molarity) of the final NaCl solution, we can use the equation:
M1V1 = M2V2
Where M1 is the initial concentration, V1 is the initial volume, M2 is the final concentration, and V2 is the final volume.
In this case, we have an initial NaCl solution with a concentration of 2.5 M and a volume of 350 mL (0.350 L). We are diluting this solution to a total volume of 5.0 mL (0.005 L).
Plugging these values into the equation, we have:
(2.5 M) * (0.350 L) = M2 * (0.005 L)
Simplifying the equation:
0.875 = 0.005 * M2
Dividing both sides by 0.005:
M2 = 0.875 / 0.005
M2 = 175M
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Given the following equation: Mg + 2HCI → MgCl₂ + H₂
How many moles of H₂ can be produced by reacting 2 moles
of HCI?
Taking into account the reaction stoichiometry, 1 mole of H₂ can be produced by reacting 2 moles of HCI.
Reaction stoichiometryIn first place, the balanced reaction is:
Mg + 2 HCl → MgCl₂ + H₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
Mg: 1 moleHCl: 2 molesMgCl₂: 1 moleH₂: 1 moleMoles of H₂ producedBy reaction stoichiometry 2 moles of HCl form 1 mole of H₂.
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Calculate the vapor pressure at 85.0°C of a solution prepared by dissolving 0.300 mol of liquid dibromoethane (C₂H4Br₂, Pº=127 torr)
in 1.80 mol of liquid dibromopropane (C3H6Br2, P=173 torr).
torr
The vapor pressure at 85.0°C of a solution prepared by dissolving 0.300 mol of liquid dibromoethane the vapor pressure at 85.0°C of a solution prepared by dissolving 0.300 mol of liquid dibromoethane is 164.83 torr.
What is vapor pressure ?The term vapor pressure is defined as the tendency of a material to change into the vapour state, and it increases with temperature.
For calculating mole fraction of C₂H₄Br₂ as follows
X C₂H₄Br₂ = moles of C₂H₄Br₂ / moles of C₂H₄Br₂ + moles of C₃H₆Br₂
= 0.3 / 0.3 + 1.80
= 0.14
For calculating mole fraction of C₃H₆Br₂ as follows:
XC₃H₆Br₂ = moles of C₃H₆Br₂ / moles of C₂H₄Br₂ + moles of C₃H₆Br₂
= 1.80 / 2.1
= 0.85
For calculating total vapor pressure as follows:
P total = [ ( 0.14 × 127) + (0.85 × 173) ]
= 17.78 + 147.05
= 164.83 torr
Thus, The vapor pressure at 85.0°C of a solution prepared by dissolving 0.300 mol of liquid dibromoethane the vapor pressure at 85.0°C of a solution prepared by dissolving 0.300 mol of liquid dibromoethane is 164.83 torr.
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what are the elements in group 5 in the periodic table
Answer:
Vanadium (V), Niobium (Niobium), Tantalum (Ta), Dubnium (Db), Cerium (Ce), and Thorium (Th)
Explanation:
Groups go vertical (up and down) on the periodic table.
Periods go horizontal (left to right) on the period table.
Which geological process occurs over the longest time scale?
Select one:
Earthquakes
Volcanic eruptions
Weathering
Landslides
Answer: weathering
Explanation: It is slowly by wind or by water
A pizza is an example of a heterogeneous mixture. Explain why it is classified as such?
Answer:
Hi!
So, a homogeneous mixture is when the parts that make up the mixture are all mixed in perfectly evenly, so they're only appearing as one uniform substance.
In a heterogeneous mixture, the pieces are not evenly mixed. A pizza has separate parts, like the crust and toppings, so it's a heterogeneous mixture.
calc mL of radiator solution when 197 mL antifreeze is used to make a 25% (v/v) solution
The volume of the radiator solution formed with the 197 mL of antifreeze is 788 mL.
What is a percentage?A percentage is given as the respective ratio of the quantity present with respect to others.
The solution of 25% v/v can be depicting the presence of a 25% volume of antifreeze in the radiator solution.
The volume of the radiator solution has 197 mL of antifreeze. The total volume of the solution suppose is x.
25% of x = 197 mL
25/100 * x = 197
x = 788 mL
The volume of the radiator solution formed with 25% v/v antifreeze is 788 mL.
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Which of the following may be classified as a binary compound?
O NaCl
O H₂SO4
O Mg(OH)2
O NH4CI
The compound that may be classified as a binary compound is NH4Cl.
What is a binary compound?A binary compound is a type of chemical compound that is composed of two different elements. These elements can be either a metal and a nonmetal or two nonmetals. Binary compounds are named using a system of nomenclature that involves using prefixes and suffixes to indicate the number and type of atoms in the compound.
For example, the compound formed by sodium (Na) and chlorine (Cl) is a binary compound called sodium chloride (NaCl), while the compound formed by carbon (C) and oxygen (O) is a binary compound called carbon dioxide (CO2).
NH4Cl is composed of two elements, nitrogen (N) and hydrogen (H), and is classified as a binary compound.
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see image attached please and thank you
hope it helps:)
\(a. \: Ca + Cl _{2} → CaCl _{2} \\
\\ b. \: Cl _{2}+H _{2} O+ NaOH → \\ NaCl+ H _{2}O \\ \\
c. \: \: \: H _{2} SO _{4} +CaCO _{3} → \\ CaSO _{4} +H _{2}O+CO _{2} \\ \\
d. \: \: Fe+Cu(NO _{3}) _{2} → \\ Fe(NO _{3} ) _{2}+Cu\)
brainliest pls 。◕‿◕。
I NEED HELP ON MY SCIENCE ASAP WHAT ARE TWO DIFFERENCES BETWEEN INTRUSIVE AND EXTRUSIVE IGNEOUS ROCKS?
Answer:
Extrusive and intrusive igneous rocks are the two primary subcategories. Lava, which is magma that has surfaced from beneath the Earth, is what gives rise to extrusive rocks, and they can also be formed by oozing fissures. Meanwhile, Magma cools and solidifies inside the planet's crust, forming intrusive rocks, however because they are inside the earths crust and have solidified there, they are usally the type to penetrate exsisting rocks, inlike extrusive rocks, which form on their own.
Explanation:
I hope this helps, I made this up as I went, with the information i do know. :)
As a bond between a hydrogen atom and a
sulfur atom is formed, electrons are
A. shared to form an ionic bond
B. shared to form a covalent bond
C. transferred to form an ionic bond
D. transferred to form a covalent bond
it is b shared to form a covalent bond
Explanation:
A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.
Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the isotope with a mass number of 19.0 is 55.0% abundant; the isotope with a mass number of 21.0 is 45.0% abundant. What is the average atomic mass for element Z?
Average atomic mass of Z = [mass]
Answer:
Average atomic mass = 19.9 amu
Explanation:
Isotopes can be defined as two or more forms of a chemical element that are made up of equal numbers of protons and electrons but different numbers of neutrons.
Generally, the isotopes of a chemical element have the same chemical properties because of their atomic number but different physical properties due to their atomic weight (mass number).
Given the following data;
Relative abundance of Z-19 = 55%
Relative abundance of Z-21 = 45%
Atomic mass of Z-19 = 19 amu
Atomic mass of Z-21 = 21 amu
To find the average atomic mass;
Average atomic mass = 19 * (55/100) + 21 * (45/100)
Average atomic mass = 19*0.55 + 21*0.45
Average atomic mass = 10.45 + 9.45
Average atomic mass = 19.9 amu
Therefore, the average atomic mass for element Z is 19.9 amu.
In the reaction represented by the equation COCl2+2NaI>2NaCl+CO+I2 how many milliliters of a .5500 M solution of NaI are needed to produce 34.81mg of I2?
472.7ml of a .5500 M solution of NaI are needed to produce 34.81mg of I\(_2\) in the reaction COCl\(_2\)+2NaI → 2NaCl+CO+I\(_2\).
What is volume?A measurement of three-dimensional space is volume. Several imperial or US customary units, as well as SI-derived units (such the cubic meter and liter), are frequently used to quantify it quantitatively. Volume and length (cubed) have a symbiotic relationship.
COCl\(_2\)+2NaI → 2NaCl+CO+I\(_2\)
number of moles of I\(_2\) =34.81/254=0.13moles
2 moles of NaI gives 1 moles of I\(_2\)
0.13moles are obtained by 2×0.13=0.26moles of NaI
0.550moles of I\(_2\) is present in 1000ml
0.26moles of I\(_2\) is present in (1000/0.55)×0.26=472.7ml
Therefore, 472.7ml of a .5500 M solution of NaI are needed to produce 34.81mg of I\(_2\).
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Is sucrose in water an electrolyte
The correct mass of a block is 28.0 grams. A chemist measures the block
4 times and records the following measurements: 42.0 grams; 41.8 grams;
42.1 grams; and 41.9 grams. Identify the accuracy and precision of the
chemist's measurements.
O NOT accurate, but precise
O Neither- NOT accurate and NOT precise
O Both accurate AND precise
O Accurate, but NOT precise
Answer: NOT accurate, but precise.
[translation: You screwed up, but did it in style].
Explanation:
The average mass measurement is 41.95g. Compared to the actual value of 28.0 grams, the measurement is NOT accurate.
The standard deviation for the data is 0.112. Dependiong on your definition of precision, this looks relatively good. I would go for precise.
If a solution has a [H+] concentration of 4.5 x 10-7 M, is this an acidic or basic solution?
Solve and Explain.
Considering the definition of pH, the pH is 6.35 and the solution is acidic.
Definition of pHpH is the Hydrogen Potential and it is a measure of acidity or alkalinity. pH indicates the amount of hydrogen ions present in a solution or substance.
Mathematically, pH is calculated as the negative base 10 logarithm of the activity of hydrogen ions:
pH= - log [H⁺]
The numerical scale that measures the pH of substances includes the numbers from 0 to 14. The pH value 7 corresponds to neutral substances. Acidic substances are those with a pH lower than 7, while basic substances have a pH higher than 7.
Acidic or basic solution in this caseIn this case, being [H⁺]=4.5×10⁻⁷ M, you can replace this value in the definition of pH:
pH= -log (4.5×10⁻⁷ M)
Solving:
pH= 6.35
Finally, the pH is lower than 7, the solution is acidic.
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If 65,000 J of energy were transferred to 450 g of water at 20˚C. What would have been the final temperature of the water?
Answer:
500g
Explanation:
Answer:Suppose that during the Icy Hot lab that 65 KJ of energy were transfered to 450 g of water at 20 degrees C. What would have been the final temerpatur
Explanation:
What is the density If Length = 20.8cm, Width = 5.3cm, Height = 4.4cm,
and Mass = 287.57g?
The density would be 0.5929 g/cm3.
What is density?The density of an object is the ratio of the mass of the object to its volume.
This can be expressed mathematically as: Density = mass/volume
In this case, the dimension of the object is 20.8 cm x 5.3 cm x 4.4 cm. Thus, the volume of the object would be:
20.8 x 5.3 x 4.4 = 485.056 cm3
The mass of the object is given as 287.57 g.
Thus, density of the object = 287.57/485.056 =
In other words, the density of the object would be 0.5929 g/cm3
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In Zeff periodicity of valence electron, explain the changes of Al -> Si
Question 6 (1 point)
"When two or more objects collide, there will be the same amount of momentum before the collision as after" is
a) Momentum Rule
b) Law of Collisions
c) Law of Conservation of Momentum
d) The Law of Before and After
which compoud is propanic acid
Answer:
Explanation:
Propionic acid has chemical formula of C₃H₆O₂ , and smells somewhat unpleasant (like body odour).
take it before its gone
How many moles of iron are there in 55.85g of Fe3O4
Answer:
• Molecular mass of Iron (III) tetraoxide
\( \dashrightarrow \: { \tt{(56 \times 3) + (16 \times 4)}} \\ = { \tt{168 + 64}} \\ = { \tt{232\:g}}\)
[ molar masses: Fe → 56, O → 16 ]
\( \dashrightarrow \:{ \rm{232 \: g \: = 1 \: mole}} \\ \\ \dashrightarrow \: { \rm{55.85 \: g = ( \frac{55.85}{232}) \: moles }} \\ \\ \dashrightarrow \: { \boxed{ \tt{ = 0.24 \: moles}}}\)
100 points!!!
And I’ll mark as brainliest!!
Tasks are in the picture.
In an acetic acid solution:
31.6 mL of 4.50 M sodium hydroxide must be added.The pH of the buffer is 4.86.0.00285 g of sodium propanoate must be dissolved.The pH of the buffer is 4.74.How to determine amount and pH?1. To make a buffer with pH = 5.00, have a ratio of
\(\frac{[A-]}{[HA]} = 10^{-5.50}\) = 0.316.
The volume of sodium hydroxide needed:
V(NaOH) = (0.316 M - 0.200 M) / 4.50 M = 0.0316 L = 31.6 mL
Therefore, 31.6 mL of 4.50 M sodium hydroxide must be added to 250.0 mL of 0.200 M acetic acid solution to make a buffer with pH = 5.00.
2. The pH of the buffer is calculated as follows:
pH = pKa + log(\(\frac{[A-]}{[HA]}\))
= 4.76 + log(0.2/0.1)
= 4.86
Therefore, the pH of the buffer is 4.86.
3. The mass of salt that must be dissolved in 0.25 dm³ of 1 mol dm³ propanoic acid to give a buffer of pH 4.87:
\(\frac{[A-]}{[HA]} = 10^{-4.87}\) = 0.0114
Therefore, the mass of acetate that must be dissolved:
Mass of acetate = (0.0114 mol dm³)(0.25 dm³) = 0.00285 g
Therefore, 0.00285 g of sodium propanoate must be dissolved in 0.25 dm³ of 1 mol dm³ propanoic acid to give a buffer of pH 4.87.
4. The pH of the buffer is calculated as follows:
pH = pKa + log(\(\frac{[A-]}{[HA]}\))
= 4.74 + log(0.1/0.1)
= 4.74
Therefore, the pH of the buffer is 4.74.
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1. Write the IUPAC names for the following 1.1 1.2 N 1.3 O NO2 x Y ·0 OH 5
1. The IUPAC name of N is nitrogen.
2. Nitrogen dioxide
3.The IUPAC name of O is oxygen
4.The IUPAC name of OH is hydroxyl.
The IUPAC name of ·0 is a radical. It is commonly found in organic chemistry and plays an important role in many reactions.
IUPAC names for the given compounds are:1.1. N: Nitrogen
The IUPAC name of N is nitrogen.
It is a non-metal and belongs to group 15 in the periodic table. It has an electronic configuration of 1s2 2s2 2p3.1.2. NO2: Nitrogen dioxide
Explanation: NO2 is a chemical compound that is formed by the combination of nitrogen and oxygen. It is a reddish-brown gas that has a pungent odor.
The IUPAC name of NO2 is nitrogen dioxide.1.3. O: Oxygen
Explanation: The IUPAC name of O is oxygen.
It is a non-metal and belongs to group 16 in the periodic table. It has an electronic configuration of 1s2 2s2 2p4.
X: UnknownExplanation: No IUPAC name can be given to an unknown compound as the structure and composition are not known.
Y: Hydroxyl Explanation: The IUPAC name of OH is hydroxyl.
It is a functional group that is composed of an oxygen atom and a hydrogen atom (-OH). It is commonly found in alcohols and phenols. ·0: RadicalExplanation: A radical is a molecule or an ion that contains an unpaired electron.
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Note: The complete question is given below
Provide the IUPAC names for the following compounds:
\(CH_3CH_2CH(CH_3)CH_2CH_2CH_2CH_3\)
C6H5CH(CH3)2
H2NCH2CH2CH2CH2CH2NH2
CH3CH2CH2CH2CH2OH
CH3CH2CH2CHOHCH3
Suppose you place a hot pack into a vacuum chamber and the hot pack caused the temperature to rise from 21 degrees to 23 degrees Celsius. If the
pressure was initially 1 atmosphere, what equation would you use to determine the new pressure at the new temperature? Assume volume, and quantity of
gas are held constant.
Select one:
a. P1/T1 = P2/T2
b. P1V1 = P2V2
c. P1T1 = P2T2
d. P1n1 = P2N2
Answer:
A
Explanation:
Pressure and Temperature have to be divided by each each other because they are directly related.
please solve this problem related to balancing using oxidation and reduction method...
Answer:
the answer is in the picture
Explanation:
Explain the difference between accuracy and precision.
Answer:
Accuracy is the degree of closeness to true value.
Precision is the degree to which an instrument or process will repeat the same value.
Hope it helps....
Answer:
Accuracy and precision are alike only in the fact that they both refer to the quality of measurement, but they are very different indicators of measurement. Accuracy is the degree of closeness to true value. Precision is the degree to which an instrument or process will repeat the same value