Answer: The [tex]K_b[/tex] for the weak base is [tex]3.5\times 10^{-3}[/tex]
Explanation:
[tex]A^-+H_2O\rightarrow HA+OH^-[/tex]
cM 0 0
[tex]c-c\alpha[/tex] [tex]c\alpha[/tex] [tex]c\alpha[/tex]
So dissociation constant will be:
[tex]K_b=\frac{[HA][OH^-]}{[A^-]}[/tex]
[tex]K_b=\frac{(c\alpha)^{2}}{c-c\alpha}[/tex]
Given :
c= 0.0910 M and pH = 10.50
pOH = 14-pH = 14-10.50 = 3.5
Also [tex]pOH=-log[OH^-][/tex]
[tex][OH^-]=antilog(-3.5)= 3.2\times 10^{-4}M[/tex]
[tex][OH^-]=c\alpha=3.2\times 10^{-4}[/tex]
[tex]K_b=\frac{(3.2\times 10^{-4})^2}{(0.0910-3.2\times 10^{-4}}[/tex]
[tex]K_b=\frac{(3.2\times 10^{-4})^2}{(0.09068}[/tex]
[tex]K_b=3.5\times 10^{-3}[/tex]
Thus [tex]K_b[/tex] for the weak base is [tex]3.5\times 10^{-3}[/tex]
The Kb for the unknown weak base is 3.5 × 10⁻³.
How we calculate the dissociation constant for a weak base?Dissociation constant for a weak base at equilibrium is the ratio of the product of concentration of product to the concentration of un-ionized base.
Chemical reaction for a weak base at initial and equilibrium state can be represented as follow:
[tex]\[\mathop {{{\rm{A}}^{\rm{ - }}}}\limits_{\scriptstyle{\rm{c}}\hfill\atop\scriptstyle{\rm{c - c\alpha }}\hfill} {\rm{ + }}{{\rm{H}}_{\rm{2}}}{\rm{O}}\mathop { \to {\rm{HA}}}\limits_{\scriptstyle{\rm{0}}\hfill\atop\scriptstyle{\rm{c\alpha }}\hfill} {\rm{ + }}\mathop {{\rm{O}}{{\rm{H}}^{\rm{ - }}}}\limits_{\scriptstyle{\rm{0}}\hfill\atop\scriptstyle{\rm{c\alpha }}\hfill} \][/tex]
Kb = [HA] [OH⁻] / [A⁻]
Kb = (c∝)² / (c - c∝)
In the question given that,
pH = 10.50
Concentration of weak base c = 0.0910 M
We know that, pOH = 14 - pH
pOH = 14 - 10.50 = 3.5
Also we now that,
pOH = -log[OH⁻]
[OH⁻] = c∝ = antilog (-3.5) = 3.2 × 10⁻⁴ M
Now we put all these values in the above equation of Kb, we get
Kb = (3.2 × 10⁻⁴)² / (0.0910 - 3.2 × 10⁻⁴) = 3.5 × 10⁻³
Hence, 3.5 × 10⁻³ is the value of Kb.
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Assign an oxidation number to each element in the reaction
The question is incomplete, the complete question is;
Assign an oxidation number to each element in the reaction.
CO(g) + 2H2(g) → CH3OH(g)
In CO, the oxidation number of C is _, and that of O is _.
In H2, the oxidation number of H is _.
In CH3OH, the oxidation number of C is _, that of O is _, and that of H is _.
Answer:
See explanation
Explanation:
If we look at the reaction, in CO, C is +2 while O is -2. Remember that the sum of all the oxidation numbers in a compound must be zero.
The oxidation number of atoms in a diatomic molecule is zero hence in H2, H is zero.
We already know the oxidation states of oxygen and hydrogen in CH3OH to be -2 and +1 respectively. Carbon is;
x + 4(1) + (-2) = 0
x + 2 =0
x = -2
Hence in CH3OH, carbon has an oxidation state of -2.
Name two elements that have similar properties based on their groupings in the periodic table.
A. Li and O
B. Na and Li
C. B and Cl
D. O and Cl
Answer:
B. Na and Li
Explanation:
Only lithium and Sodium will have similar properties based on their groupings in the periodic table.
The periodic table of elements shows the arrangement of elements based on their atomic number.
As general rule, elements in the same group on the periodic table will have the same chemical propertiesThis is because they have the same number of valence electrons. Valency of an atom determines the chemical properties of such atom.Zinc (Zn) can be described as a bluish-white metal that is brittle at room
temperature, conducts heat and electricity, and burns in air.
Which of the following is a chemical property of zinc?
A. Zinc is brittle at room temperature.
B. Zinc burns in air.
C. Zinc is bluish-white.
D. Zinc conducts heat
Answer:
B. Zinc burns in the air.
Explanation:
A chemical property of an element is known as the property of that specific element that is apparent or visible when the element has gone through a chemical reaction with other substances or elements under investigation.
In this case, the correct answer is option B which is " Zinc burns in the air" because it shows zinc to react chemically with air which then changes its properties.
The others are just physical properties of zinc
A 60.0 mL sample of nitrogen is warmed from 350 K to 400 K. Find its new volume if the pressure remains constant.
0.0145 ml
52.50 ml
0.0191 ml
68.57 ml
yes
Answer:68.57
Explanation:
What would be the new pressure if a 400 mL gas sample at 380 mm Hg is expanded to 800 mL with no change in temperature
Answer:
25 atm or 190mmHg
Explanation:
Since Temperature is constant we dont need to worry about it so.
P1V1=P2V2
Rewritten as (P1xV1)/V2 Always use liters in gas laws
I Prefer atm so ill convert to that to use in the equation.
(.5atmx.4L)/.8L =.25 atm or 190mmHg
(You can convert mmHg to atm by dividing by 760)
Calculate the density (in g/mL) of an object that has a mass of 3.81 g and a volume of
14.3 mL.
Answer:
Density = M/V
so 3.81/14.3 .266g/ml
Explanation:
A weak base reacts with a strong acid to form the salt ammonium nitrate. What is the chemical formula of the weak base?
Answer:
ammonia: NH₃
Explanation:
The product is ammonium nitrate, with the chemical formula NH₄NO₃. This salt is composed of the cation NH₄⁺ and the anion NO₃⁻
Nitrate (NO₃⁻) is formed from the strong acid called nitric acid: HNO₃.
Ammonium ion (NH₄⁺) is formed from the weak base ammonia: NH₃.
Thus, the chemical reaction for the formation of the salt is the following:
HNO₃ + NH₃ ⇒ NH₄NO₃
You dissolved a small amount of your product in about 5 mL of distilled water in a test tube. You then added about 1 mL of 6M HCl solution and finally you heated the final solution. What precipitate formed in the test tube?
Answer:
Sulfur
Explanation:
The reaction of the following question is as follows:
Na₂S₂O₃ (aq) + 2HCl(aq) --------------⇒2NaCl (aq) + H₂O(l) + SO₂(aq) + S (s)
Precipitate is sulfur.
I need help with this question
Answer:
kajjajjanwjsjjsjsjsjsjjsjsj
Explanation:
jqqjjqj
CHEMISTRY PLEASE HELP ITS MY FINAL
Answer:
1. Periodic Table
2. Periods
3. Groups
4. Metals
5. Non - Metals
6. Metalloids
7. Alkaline Metals
8. Transition Metals
Explanation:
i hope this was right. Tell me if it was wrong.
Answer:
1. Periodic table
2. Periods
3. Groups
4. Metals
5. Nonmetals
6. Metalloids
7. Representative elements
8. Transitition metals
Explanation:
Note for the 7th blank: it's either representative elements or main group elements. I'm not sure what terminology is on your vocab list, so keep that in mind. Good luck on your final!
Do the following math operation and report your answer to the
correct number of significant digits.
10.000-9.768/5.78
The following math operation and report your answer to the
correct number of significant digits is. 4.013×10^-2
now we have given 10.000-9.768/5.78,
we have to find correct significant digits
10.000-9.768 ÷5.78
=0.232÷5.78
=0.04013, it has 4 significant figure
we have to write in significant digit
so 0.04013 = 4.013×10^-2
Instead of expressing the magnitude of a measured number, significant figures or digits do so. The last digit, whose value is only roughly known, and the number of precisely known digits together make up the important figures, according to scientific tradition.The laws of arithmetic, addition, subtraction, multiplication, and division, are used to calculate any measurement because the significant figures represent numbers. Because any measurement is calculated by compounding two or more variables, these calculated results may have been measured with varying degrees of accuracy and are inevitably flawed.To know more about significant digit
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what is meant by votalite in chemistry
Answer: This may help you
https://ay.live/BNNBhX
Explanation:
What mass of N2 will be needed to produce 31.5 grams of N2O5?
4N2 + 502 --> 2N2O5
a) 158.3 grams
b) 38.64 grams
c) 4.96 grams
d) 16.34 grams
Answer: d) 16.34 grams
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} N_2O_5=\frac{31.5g}{108.01g/mol}=0.292moles[/tex]
[tex]4N_2+5O_2\rightarrow 2N_2O_5[/tex]
According to stoichiometry :
As 2 moles of [tex]N_2O_5[/tex] are produced by= 4 moles of [tex]N_2[/tex]
Thus 0.292 moles of [tex]N_2O_5[/tex] are produced by= =[tex]\frac{4}{2}\times 0.292=0.584moles[/tex] of [tex]N_2[/tex]
Mass of [tex]N_2=moles\times {\text {Molar mass}}=0.584moles\times 28g/mol=16.34g[/tex]
Thus 16.34 g of [tex]N_2[/tex] will be needed
Answered
A student wants to measure the temperature of a solution. The student
takes 10 measurements and determines that the temperature is about 24.6 degrees celsius. If the true temperature is 24.3 degrees celsius, what is the absolute error in the measurement?
Answer:
0.3 or 0.30
Explanation:
The discrepancy between a quantity's measured or inferred value and its actual value is known as the absolute error. The absolute error is insufficient because it provides no information about the significance of the error. The absolute error is -0.3.
An important component of scientific calculations is measurement. Results from measurements that are entirely correct are incredibly unusual. Small mistakes are frequent while monitoring various metrics. Different kinds of errors result in variations in measurement. Mathematical equations can be used to express all faults.
The difference between a quantity's measured value and actual value is used to compute the absolute error. The absolute error is written as, if the measured value is x and the actual value is x₀.
∆x = x₀- x
∆x = 24.3 - 24.6
∆x = -0.3
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What is the formula of tin (II) acetate?
Answer:
Sn(C2H3O2)2
Explanation:
C2H3O2 is Acetate
Sn is tin
Acetate has a -1 charge
In order for tin to have a +2 charge, we need two acetates
So we write it as (C2H3O2)2
You just leave Sn blank because of the roman numeral and since it is a transition metal.
So the answer is Sn(C2H3O2)2
Answer:
[tex]\boxed {\boxed {\sf Sn (C_2 H_3 O_2)_2}}[/tex]
Explanation:
First, find what tin and acetate is.
Acetate: C₂H₃O₂ Tin: SnNext, find the charge on acetate, which is -1.
The Roman Numeral 2 in parentheses after tin (II), signifies that the tin has a charge of +2.
We need to balance the charges, so they will equal 0.
1 acetate= -1 Tin = +2The best way to balance is by using 2 acetate molecules
2 acetate = -2 Tin = +2 -2 +2=0If we want 2 acetate molecules, we must add a subscript of 2 after acetate.
Acetate: C₂H₃O₂ 2 Acetate: (C₂H₃O₂)₂Add the tin (Sn) in front
Tin (II) Acetate: Sn (C₂H₃O₂)₂The formula for tin (II) acetate is Sn (C₂H₃O₂)₂
Can gravity be considered a force even though the objects are not in contact?
Answer:
Gravity as well as electrostatic and magnetic attraction and repulsion provide real life examples of forces being exerted by one object on another without them being in contact with each other.
Pls vote for brainliest...
At birth, mammal babies are:
A weak and vulnerable
B strong and independent
C ready to leave their mothers
D able to find their own food
Answer:
It's A: Weak & Vulnerable
Anyone knows the answer?
Answer:
No I do not but did you know that you can save 15 or more on car insurance by switching to geico?
Explanation:
How many protons, neutrons, and electrons does the following atom have?
Answer:
Option C 28 Proton 31 neutron 26 elecrtons
Explanation:
If a sample originally had 410 atoms of carbon-14, how many atoms will remain after 16,110 years?
Answer:
58.4 atoms
Explanation:
To find the remaining amount of atoms, you need to use the half-life formula:
[tex]A = A_0*(\frac{1}{2})^{\frac{t}{h}[/tex]
In this formula,
-----> A = remaining amount (atoms)
-----> A₀ = initial amount (atoms)
-----> t = time passed (years)
-----> h = half-life (years)
The half-life is the amount of time that needs to pass for the initial amount of a substance to decay by 50% (or 1/2). According to the graph, 50% of the initial substance is left after 5,730 years.
A = ? atoms t = 16,110 years
A₀ = 410 atoms h = 5,730 years
[tex]A = A_0*(\frac{1}{2})^{\frac{t}{h}[/tex] <----- Half-life formula
[tex]A = 410*(\frac{1}{2})^{\frac{16,110}{5,730}[/tex] <----- Insert values
[tex]A = 410*(\frac{1}{2})^{2.81[/tex] <----- Divide 16,110 by 5,730
[tex]A = 410*0.142[/tex] <----- Raise [tex]\frac{1}{2}[/tex] to 2.81
[tex]A = 58.4[/tex] <-----Multiply 410 and 0.142
I need answers to all of them
Answer:
Compound 1: Carbon Dioxide (CO_2)
Compound 2: Water (H_2 O)
Compound 3: Potassium Nitrate (KNO_3)
Compound 4: I am unsure
Compound 5: Calcium Sulfate
Explanation:
A gaseous fossil fuel produced from organic matter that is used to heat homes and cook
Answer:
Natural gas
Explanation:
Natural gas is a gaseous fossil fuel produced from organic matter that is used to heat homes and cook food.
Natural gas is one of the most volatile part of hydrocarbons that exist together with fossil fuel.
In a reservoir, natural gas is usually on top of the fossil fuel reserve. It can also be distilled from crude oil as they rises up on top of the column first due to their low boiling pointThe gas mixture is made up light hydrocarbons from methane to hexane.What mass of Nz will be needed to produce 31.5 grams of N2O5?
4N2 + 502 --> 2N2O5
a) 158.3 grams
b) 38.64 grams
c) 4.96 grams
d) 16.34 grams
Answer: d) 16.34 grams
Explanation:
To calculate the moles :
[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]
[tex]\text{Moles of} N_2O_5=\frac{31.5g}{108.01g/mol}=0.292moles[/tex]
The balanced chemical reaction given is:
[tex]4N_2+5O_2\rightarrow 2N_2O_5[/tex]
According to stoichiometry :
As 2 moles of [tex]N_2O_5[/tex] are produced by= 4 moles of [tex]N_2[/tex]
Thus 0.292 moles of [tex]N_2O_5[/tex] are produced by= =[tex]\frac{4}{2}\times 0.292=0.584moles[/tex] of [tex]N_2[/tex]
Mass of [tex]N_2=moles\times {\text {Molar mass}}=0.584moles\times 28g/mol=16.34g[/tex]
Thus 16.34 g of [tex]N_2[/tex] will be needed
The magnet on the right is moved toward the suspended magnet on the left.
Which statement describes the interactions of the magnets in terms of their magnetic fields
When the magnet on the right is moved toward the suspended magnet on the left, a repulsive force between the two magnets causes the suspended magnet to swing to the left; option B
What are magnets?Magnets are materials which exhibit magnetism or produces a magnetic field.
Magnets attract other objects to themselves and these objects are said to be magnetic.
Magnetic objects include metals such as iron.
A magnet has two ends called poles. The poles of a magnet are the North and South pole.
Magnetic lines of forces begin at the North pole whereas magnetic lines of forces end in at the south Pole.
The law of magnetism states that like poles of a magnet repel each other while unlike poles attract.
Considering the given magnets;
the magnet on the right is moved toward the suspended magnet on the left causing the suspended magnet to move to the left means that the end of the magnets repel each other.
This implies that the ends are two similar ends of the magnets.
In conclusion, unlike ends of a magnet attract whereas unlike ends repel.
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Note that the complete question is given below:
The magnet on the right is moved toward the suspended magnet on the left.
Which statement describes the interactions of the magnets in terms of their magnetic fields?
A. A repulsive force between the two magnets causes the suspended magnet to swing to the left.
B. A repulsive force between the two magnets causes the suspended magnet to oscillate like a pendulum.
C. An attractive force between the two magnets causes the suspended magnet to swing to the right.
D. An attractive force between the two magnets cause the suspended magnet to oscillate like a pendulum.
Which of the following units of length is the smallest?
kilometer
inch
meter
foot
centimeter
Identify the nuclide produced when fluorine-18 decays by positron emission:
18 9F→01e + ?
Answer:
jdkskdkakalalalalalakandnxkdmymy
Please show work:
Question below
Answer:
b) 2.0 mol
Explanation:
Given data:
Number of moles of Ca needed = ?
Number of moles of water present = 4.0 mol
Solution:
Chemical equation:
Ca + 2H₂O → Ca(OH)₂ + H₂
now we will compare the moles of Ca and H₂O .
H₂O : Ca
2 : 1
4.0 : 1/2×4.0 = 2.0 mol
Thus, 2 moles of Ca are needed.
On the periodic table, Nitrogen has 7 what?
Answer:
[tex]\boxed {\boxed {\sf 7 \ protons}}[/tex]
Explanation:
On the Periodic Table, Nitrogen is:
A nonmetalIn group 15 and period 2 With an atomic mass of 14.007 amu With the atomic number 7In elements, their atomic number is also equal to the number of protons. As the number of protons in an atom change, so does the identity of the atom.
Since nitrogen has an atomic number of 7, it must always have 7 protons
HelapPPPpPPPPpThe three states of matter that may change during a physical change are O atoms, molecules, electrons O color, shape, size O solid, liquid, gas
Answer:
Solid liquid and gas
Explanation:
Titanium dioxide and zinc oxide are two of the 16 active ingredients approved by the FDA for use in sunscreens. Which compound contains a higher percentage of oxygen by mass
Answer: [tex]TiO_2[/tex] has higher percentage of oxygen by mass.
Explanation:
To calculate the mass percent of element in a given compound, we use the formula:
[tex]\text{Mass percent of oxygen}=\frac{\text{Mass of oxygen}}{\text{mass of compound}}\times 100[/tex]
1. Mass of oxygen in [tex]TiO_2[/tex] = [tex]\frac{32g}{80g}\times 100=40\%[/tex]
2. Mass of oxygen in [tex]ZnO[/tex] = [tex]\frac{16g}{81g}\times 100=19.8\%[/tex]
Thus [tex]TiO_2[/tex] has higher percentage of oxygen by mass.
The compound with the higher percentage of oxygen by mass is titanium dioxide.
Titanium dioxide, TiO2, has a molar mass of 79.866 g/mol and O2 has a molar mass of 32.
Percentage by weight of oxygen in TiO2 = 32/79.866 x 100
= 40.07%
Zinc oxide, ZnO, has a molar mass of 81.38 g/mol
percentage by weight of oxygen in ZnO = 16/81.38 x 100
= 19.66%
Thus, titanium dioxide has a higher percentage by weight of oxygen than zinc oxide.
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