How did Darwin study artificial selection in the late 1800's?
A. He studied the animals on the Galapagos Island.
B. He studied selectively bred animals.
C. He studied the animals in a Zoo.
D. He studied animals in the wild.
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.
12. If you had 375 K, what would the temp be in Celsius?
a. 648°C
c. 500°C
b. 435°C
d. 102°C
Answer:
As Per Provided Information
Given temperature is 375K
We have been asked to find the temperature in Celcius .
[tex] \boxed{\bf \: {}^{ \circ}C =Given \: Temperature \: in \: k \: - 273}[/tex]
Substituting the given value in above equation and let's solve it
[tex] \qquad \longrightarrow\sf \: {}^{ \circ}C = \: 375 - 273 \\ \\ \\ \qquad \longrightarrow\sf \: {}^{ \circ}C = \: 102[/tex]
Therefore,
Temperature in Celcius will be 102 °CSo, your answer is d) 102°C
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%.
The thick old crust of earth is crust
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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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
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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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
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
how many oxygen atom in 0.25 mol ca(No3)2?
Answer:
1 molecule of Ca(NO3)2 has 6 oxygen atoms.
If you have 2m of hydrochloric acid and also 2m of vinegar which one is weak and strong and why?
experimental evidence indicates that the nucleus of an atom
The nucleus of an atom is positively charged and contains most of the mass if the atom.
What is an atom?An atom is the smallest particle of a an element that can take part in a chemical reaction.
Atoms are made up of other smaller sub-particles which are:
neutrons which are neutral protons which are positively charged electrons which are negatively chargedThe protons and neutrons are found in the nucleus of an atom
The electrons are found regions around the nucleus.
Due to the positive charge of the protons, the nucleus of an atom are positively charged and is massive.
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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.
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
If you have 146.0 grams of HCl, how many grams of H2O can that produce?
Answer:
9 gram of H2O can be produced
The table below lists three characteristics of an atom of an element
Number of protons:10
Number of neutrons:10
Number of Valence Electrons:8
An atom of which element is described by the data in the table?
what is joule ?
a. time
b. mass
c. volume
d. length
e. none
Explanation:
It is the unit of work or energy
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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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.
What 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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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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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 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.
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
Ten grams of water will require --- calories to raise the temperature 1° C.
Explanation:
Specific heat capacity of water is 1cal/g/∘C. 1 cal heat is required to increase the temperature of 1 g of water by 1∘C. To increase the temperature of 10 g water by 1∘C, 10 calories of heat is required
PLEASE MARK ME BRAINLIEST IF MY ANSWER IS CORRECT PLEASEAre two atoms of the same element identical?
Answer: No, two atoms belonging to the same chemical element are not necessarily identical.
Explanation:
I hope that was helpful
14. Which statement gives you enough information to say that the atom is electrically neutral?
A. The atom has 15 neutrons and 15 electrons.
B. The atom has 19 electrons and 19 neutrons.
C. The atom has 4 neutrons and 4 protons.
D. The atom has 7 protons and 7 electrons
The statement which gives you enough information to say that the atom is electrically neutral is: The atom has 7 protons and 7 electrons.
Identify each compound as an electrolyte or a nonelectrolyte.
MgCl, (magnesium chloride)
CH, On (sucrose table sugar)
H, SO. (sulfuric acid)
DONE
The following solutions are electrolytes/non electrolytes;
magnessium chloride- electrolytesucrose - non electrolytesulfuric acid - electrolyteWhat is an electrolyte?An electrolyte is a substance that conducts electricity in solution. An electroyte must be able to dissociate into ions. It is these ions that are the charge carriers in solution.
Now let us define which of these are electrolytes;
magnessium chloride- electrolytesucrose - non electrolytesulfuric acid - electrolyteLearn mlore about electrolyte : https://brainly.com/question/27132799
Answer:
A B A
Explanation:
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.)