Answer:
It is:
55
Mn
25
You wish to prepare a buffer containing CH3COOH with a pH of 5.14. If the pka of acetic acid is 4.74, what ratio of
[CH3COO-]/[CH3COOH] must you use?
A 0.70
B 4.0
C 0.40
D 2.0
E 2.5
Answer:
E
Explanation:
Recall the Henderson-Hasselbalch equation:
[tex]\displaystyle \text{pH} = \text{p}K_a + \log \frac{[\text{Base}]}{[\text{Acid}]}[/tex]
For a pH of 5.14 with the given pKa of 4.74, solve for the ratio between acetate and acetic acid:
[tex]\displaystyle \begin{aligned} (5.14) & = (4.74) + \log\frac{[\text{CH$_3$COO$^-$}]}{[\text{CH$_3$COOH}]} \\ \\ \log\frac{[\text{CH$_3$COO$^-$}]}{[\text{CH$_3$COOH}]}& = 0.40 \\ \\ \frac{[\text{CH$_3$COO$^-$}]}{[\text{CH$_3$COOH}]} & = 10^{0.40} \\ \\ & = 2.5\end{aligned}[/tex]
In conclusion, the answer is E.
Please show work, thanks!
In chemistry, “partial pressure” refers to the pressure that each gas in a gas mixture exerts against its surroundings, such as a sample flask, a diver’s air tank, or the boundary of an atmosphere. You can calculate the pressure of each gas in a mixture if you know how much of it there is, what volume it takes up, and its temperature. You can then add these partial pressures together to find the total pressure of the gas mixture, or, you can find the total pressure first and then find the partial pressures.
Insoluble sulfide compounds are generally black in color. Which of the following combinations could yield a black precipitate? a) Na2S(aq) + KCl(aq) b) Li2S(aq) + Pb(N03)2(aq) c) Pb(C103)2(aq) + NaNO3(aq) d) AgNo3(aq) + KCl(aq) e) K2S(aq) + Sn(N03)4(aq)
Answer:
b) Li2S(aq)+Pb(NO3)2(aq)
e) K2S(aq)+Sn(NO3)4(aq)
Explanation:
they are the only two of the options that contain a sulfide ion (S) therefore they are the only ones that could be considered in the question.
b) Li2S(aq)+Pb(NO3)2(aq)
e) K2S(aq)+Sn(NO3)4(aq)
How many electrons are in the n = 2 shell of a magnesium atom?
Answer:
eight
Explanation:
That means there are 12 electrons in a magnesium atom
hope this helps
what is joule ?
a. time
b. mass
c. volume
d. length
e. none
Explanation:
It is the unit of work or energy
What is the IUPAC name for the compound shown?
Answer:
2,2,3-trimethylpentane
Explanation:
The iupac name for the compound shown is 2,2,3-trimethylpentane
What family kept the kings of Nepal under guard and would not let them have any power.
Answer:
Gyanendra of Nepal
If you have 2m of hydrochloric acid and also 2m of vinegar which one is weak and strong and why?
3.Calculate the pH of a 0.250 M solution of potassium phenolate, KC6H5O. Ka for phenol (C6H5OH) is 1.0 x 10-10.
From the statement and the information available in the question, the pH of the solution is 12.2.
What is Ka?The term Ka refers to the acid dissociation constant of a substance, we can obtain this by setting up the ICE table as shown;
C6H5O^- + H2O ⇄ C6H5OH + OH^-
I 0.250 0 0
C -X +X +X
E 0.250 -x x x
Now;
Kb = 1 * 10^-14/ 1.0 x 10-10
Kb = 1 * 10^-4
Kb = [C6H5OH] [OH^-]/[C6H5O^-]
1 * 10^-4 = x^2/ 0.250 -x
1 * 10^-4 (0.250 -x) = x^2
2.5 * 10^-4 - 1 * 10^-4 x = x^2
x^2 + 1 * 10^-4 x - 2.5 * 10^-4 = 0
x=0.016 M
Given that; [C6H5OH] = [OH^-] =x
pOH = -log(0.016 M) = 1.8
pH = 14 - 1.8 = 12.2
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how many oxygen atom in 0.25 mol ca(No3)2?
Answer:
1 molecule of Ca(NO3)2 has 6 oxygen atoms.
PLEASE HELP 50 Points which of Erwin Shrodinger's contributions are present in the modern atomic model and which were eventually disproven and thus are not part of the modern model?
Answer:yes is yes = 0iq
Explanation: hes was a prodogy he helped alot of people -500iq
This question is in my General Chem 2 class. I will give Brainlist!
Given: 8As + 12H20 —>3H2AsO4- + 3H+ + 5AsH3 What mass of arsenic is required to produce 15.0 mL of 0.0852M H2AsO4-?
A. 0.0359 g
B. 0.255 g
C. 17.0 g
D.1134 g
Answer:
B
Explanation:
From the given chemical equation, we want to determine the mass of arsenic necessary to produce 15.0 mL of 0.0852 M H₂AsO₄⁻.
Find the amount of moles present in 15.0 mL of 0.0852 M H₂AsO₄⁻ solution. Recall that M = mol/L:
[tex]\displaystyle 15.0\text{ mL} \cdot \frac{0.0852\text{ mol H$_2$AsO$_4^-$}}{1\text{ L}} \cdot \frac{1\text{ L}}{1000\text{ mL}} = 0.00128\text{ mol H$_2$AsO$_4^-$}[/tex]
With stoichiometric ratios and molecular weights, determine the mass of arsenic necessary:
[tex]\displaystyle 0.00128 \text{ mol H$_2$AsO$_4^-$} \cdot \frac{8\text{ mol As}}{3\text{ mol H$_2$AsO$_4^-$}}\cdot \frac{74.92\text{ g As}}{1\text{ mol As}} = 0.256\text{ g As}[/tex]
In conclusion, the answer is B.
The thick old crust of earth is crust
How do you think life on Earth would be different without the evolution of angiosperms? Provide two examples, each with an explanation.
PLSSS HURRRYYY!!!!!! WILL GIVE BRAINLIEST!!!
Answer:
Without angiosperms, average annual rainfall in the area declined by 300 millimeters. In the eastern Amazon basin, the length of the wet season decreased by nearly 3 months. The extent of the wettest rainforests, which receive more than 100 millimeters of rain per month, shrank by 80%.
Which of the following mixtures cannot be separated by using both particle size and color as observable properties?
(A) Nickels and pennies
(B)Sand and rocks
(C) Stick and stones
(D)Salt and beans
Answer:
(A) Nickels and pennies
If you have 146.0 grams of HCl, how many grams of H2O can that produce?
Answer:
9 gram of H2O can be produced
How many Calories are contained in one tablespoon of palm oil, which has 45.3 g of fat? [Hint: One
gram of protein or one gram of carbohydrate typically releases about 4 Calg, while fat releases 9
Cal/g.] Report your answer to 1 significant figure.
Answer:
120 calories
Explanation:
Calories and nutrition for world population. One tablespoon of palm oil has 120 calories and 13.6 grams of fat. What does it tell you? Of the 13.6 grams of fat in a tablespoon of palm oil, 6.7 grams are saturated and 6.3 grams are unsaturated.
A sample of water goes through a temperature change of -74.14 °C while releasing 578.7 joules of heat. The specific heat capacity of water is 4.184 J/(g·°C). What is the mass of this sample? grams (Report your answer using 4 significant figures).
Answer:
[tex] \boxed{ \sf \: m = 1.866 \: grams}[/tex]
Explanation:
Given:
Change in temperature ∆T= -74.14°C
Heat(Energy) released Q= 578.7 joules
Specific heat capacity s = 4.184 J/(g·°C)
To find:
Mass of the sample (m)=?
Solution:
[tex] \sf s= \frac{Q}{m \cdot \Delta T} \\ \sf \: Substituting \: the \: given \: parameters \\ \sf 4.184 = \frac{578.7}{m \times ( - 74.14)} \\ \sf m = \frac{578.7}{4.184 \times ( - 74.14)} \\ \sf m = \frac{578.7}{310.20176} \\ { \sf m = 1.8655 \approx1.866 \: grams}[/tex]
Since, we need the answer in 4 significant figures,
[tex] \boxed{ \sf \: m = 1.866 \: grams}[/tex]
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Many cigarette lighters contain liquid butane, C4H10, which has a ∆H°ƒ = –147.6 kJ/mol. Using enthalpies of formation, calculate the quantity of heat produced when 1.0 g of butane is completely combusted in air. (Write the equation for the process first)
For cigarette lighters containing liquid butane, C4H10, the quantity of heat produced is mathematically given as
q= -49.2 KJ
What is the quantity of heat produced when 1.0 g of butane is completely combusted in air?Generally, the equation for the Chemical reaction is mathematically given as
C₄H₁₀(l) + 6.5 O₂(g)---->4 CO₂(g) + 5 H₂O(l)
Therefore
dH°r = .(-393.5 ) + 5.(-285.5] - [1.(-147.6 )+6.5.
dH°r = -2853.9 kJ/mol
In conclusion, No.of mole
Nm = 1g/58g/mol
Nm= 0.01724mol
Hence, Heat of combustion
q = dH°r x moles
q = -2853.9 ×0.01724
q= -49.2 KJ
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Which subshells (s, p, d, f, or g) can have electrons with the indicated magnetic quantum number (ml)?
Answer:
=3 means is 3 or greater so that would be f and g subshells
=0 means is 0 or greater so that would be s, p, d, f and g subshells
=1 means is 1 or greater so that would be p, d, f, and g subshells
=4 means is 4 or greater so that would be g only
How many moles of CO2 will be produced in the following reaction if the initial amount of reactants was 0.50 moles?
2NaHCO3 —> Na2CO3 + CO2 + H2O
Answer:
In the following reaction, how many moles of
CO2
can be made by reacting 0.50 moles of
CH4
with excess oxygen?
CH4+O2>CO2+H2O
Explanation:
b. A silver ring contains 1.1 × 1022 silver atoms. How many moles of silver are in the ring?
Answer:
1124.2
Explanation:
just easy mathamatics
Which pictures shows the proper structure of the water molecule? Click the picture to see each choice.
The third picture is the answer
Explanation:
there are 2 hydrogen atom 1 oxygen
What pressure is exerted by 901.3 g of CH4 in a 0.690 L steel container at 185.7 K
Ideal gas law: PV = nRT
Write down what you know and what you want to fine:
P = pressure = ?
V = volume in liters = 0.950 L
n = moles = 727.2 g x 1 mol CH4 / 16 g = 45.45 moles
R = gas constant = 0.0821 Latm/Kmol
T = temperature in K = 221.9K
Solve for P:
P = nRT/V = (45.45)(0.0821)(221.9) / 0.950
P = 872 atm (3 sig. figs. based on 0.950 L having 3 s.f.)
How many grams of CO2 ( Carbon dioxide gas ) will exert a pressure of 769 mmHg at a volume of 52.3L at 425K?
66.9 grams of CO₂ ( Carbon dioxide gas ) will be required to exert the given value of pressure at the given volume and temperature.
Ideal Gas LawThe Ideal gas law or general gas equation emphasizes on the state or behavior of a hypothetical ideal gas. It states that "the pressure multiplied by volume is equal to moles multiply by the universal gas constant multiply by temperature.
It is expressed as;
PV = nRT
Where P is pressure, V is volume, n is the amount of substance, T is temperature and R is the ideal gas constant ( 0.08206 Latm/molK )
Given the data in the question;
Pressure P = 769 mmHg = 1.01184atmVolume V = 52.3LTemperature T = 425KAmount of gas n = ?To determine the amount of gas, we substitute our values into the expression above.
PV = nRT
n = PV / RT
n = ( 1.01184atm × 52.3L ) / ( 0.08206Latm/molK × 425K )
n = 52.919232Latm / 34.8755Latm/mol
n = 1.52mol
Now, we the mass of CO₂ ( Carbon dioxide gas ).
Molar mass of CO₂ is 44.01 g/mol
Hence;
1.52mol × 44.01 g/mol = 66.9g
Therefore, 66.9 grams of CO₂ ( Carbon dioxide gas ) will be required to exert the given value of pressure at the given volume and temperature.
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How do I solve this
Answer:
try doing a math problem it may help
Explanation:
If 53.6 g of Cu(NO3)2 were produced, how many grams of Cu reacted?
Answer:
The amount of grams of Cu that reacted is 18.15g
Explanation:
Where:.
Cu= 63.5
O= 16
N= 14
Molar mass of Cu(NO3)2 =
63.5 + 2(14+ 48)
63.5 + 124
=187.5
THEN IF 63.5g of Cu reacted in 187.5g of Cu(NO3) 2
x of Cu is in - - - - >53.6g
x= 63.5 * 53.6/187.5
x= 3403.6/187.5
x= 18.15g of Cu reacted.
PLEASE HELP 50 POINTS NO ROBOTS OR I WILL REPORT Which functional group does the molecule below contain?
H
H-C-C
H
H
O A. Ether
O B. Amino
O C. Hydroxyl
• D. Carbonyl
Answer:
D. carbonyl
Explanation:
A C=O group is present, otherwise known as a carbonyl groupWhat does thermodynamics study?
A. The properties of the nucleus
B. The strength of chemical bonds
C. The energy of motion and heat
D. The behavior of charged particles
Thermodynamics is the science that deals with work, temperature and heat. It studies the energy of motion and heat. Thus, option C is accurate.
What is thermodynamics?Thermodynamics, thermo means heat and energy and dynamics means motion or movement. It is a branch of science that relates the entropy, enthalpy, and motion of matter.
It is used in physics and chemistry to depict the change in the system influenced by the surrounding. The release or the gain of heat in a thermodynamic system is studied as well.
Therefore, in option C the energy of motion and heat are studied in thermodynamics.
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19. Which reaction will form a salt and water?
Aa precipitation reaction
Ba displacement reaction
Can acid-base neutralization
Dan ionic dissociation reaction
Answer:
acid-base neutralization
Explanation: When a base and acid react, it neutralizes the substance making it a neutral substance, which is water and a salt