Calculate the pKa of lactic acid (CH3CH(OH)COOH) given the following information. 3.005 grams of potassium lactate are added to 100. mL of a 0.500 M lactic acid solution producing a pH of 3.526.
Answer:
[tex]\displaystyle \text{p} K_a \approx 3.856[/tex]
Explanation:
Because 3.005 grams of potassium lactate is added to 100. mL of solution, its concentration is:
[tex]\displaystyle \begin{aligned} \left[ \text{KC$_3$H_$_5$O$_3$}\right] & = \frac{3.005\text{ g KC$_3$H_$_5$O$_3$}}{100.\text{ mL}} \cdot \frac{1\text{ mol KC$_3$H_$_5$O$_3$}}{128.17 \text{ g KC$_3$H_$_5$O$_3$}} \cdot \frac{1000\text{ mL}}{1\text{ L}} \\ \\ &= 0.234\text{ M}\end{aligned}[/tex]
By solubility rules, potassium is completely soluble, so the compound will dissociate completely into potassium and lactate ions. Therefore, [KC₃H₅O₃] = [C₃H₅O₃⁺]. Note that lactate is the conjugate base of lactic acid.
Recall the Henderson-Hasselbalch equation:
[tex]\displaystyle \begin{aligned}\text{pH} = \text{p}K_a + \log \frac{\left[\text{Base}\right]}{\left[\text{Acid}\right]} \end{aligned}[/tex]
[Base] = 0.234 M and [Acid] = 0.500 M. We are given that the resulting pH is 3.526. Substitute and solve for pKₐ:
[tex]\displaystyle \begin{aligned} (3.526) & = \text{p}K_a + \log \frac{(0.234)}{(0.500)} \\ \\ 3.526 & = \text{p}K_a + (-0.330) \\ \\ \text{p}K_a & = 3.856\end{aligned}[/tex]
In conclusion, the pKₐ value of lactic acid is about 3.856.
can someone help me here please
Answer:
150 mL4560 torrExplanation:
Applying Boyle's Law :
Q1
P₁V₁ = P₂V₂1.5 x 500 = 5 x V₂V₂ = 500/5 x 1.5V₂ = 100 x 1.5V₂ = 150 mLQ2
P₁V₁ = P₂V₂1 atm = 760 torr4 x 1.5 x 760 = 1 x P₂P₂ = 6 x 760P₂ = 4560 torrFatty acids can be ____________ , meaning they contain double bonds, or they can be ____________ , meaning they contain no double bonds
what controls the volumes of water in each cylinder once equilibrium is established?
The increase in volume shift the equilibrium towards making more moles of gas, decrease in volume shift the equilibrium towards producing fewer moles of gas.
What is equilibrium?The equilibrium of the gas is based on the pressure of the gas. With the increase in pressure, the equilibrium moves towards making fewer molecules of gas.
The gas equilibrium is proportional to the equilibrium K.
Increase in volume shift the equilibrium towards making more moles of gas, decrease in volume shift the equilibrium towards producing fewer moles of gas.
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What is the name of this structural formula?
Answer:
Methylamine
Explanation:
First count how many carbons there are (there's one). This will give the prefix meth-
Next we can see that this is in the organic functional group amine, as it has a nitrogen at the end with no oxygens. This will give it the suffix -amine.
Now we can give this compound a name:
Methylamine
(the yl is a suffix to make the meth- prefix complete)
How can you measure the volume of air inside of a balloon?
You could let the air out of the balloon while it is under the water with a container filled with water upside down over it. And measure the water displacement.
What is the percent yield if the quantity of reactants is sufficient to produce 0.86g of
NaCl but only 0.71g is obtained?
Taking into account definition of percent yield, the percent yield for the reaction is 82.56%.
Definition of percent yield
The percent yield is the ratio of the actual return to the theoretical return expressed as a percentage.
The percent yield is calculated as the experimental yield divided by the theoretical yield multiplied by 100%:
[tex]percent yield= \frac{actual yield}{theorical yield}x100[/tex]
where the theoretical yield is the amount of product acquired through the complete conversion of all reagents in the final product, that is, it is the maximum amount of product that could be formed from the given amounts of reagents.
Percent yield for the reaction in this case
In this case, you know:
actual yield= 0.71 gramstheorical yield= 0.86 gramsReplacing in the definition of percent yields:
[tex]percent yield= \frac{0.71 g}{0.86 g}x100[/tex]
Solving:
percent yield= 82.56%
Finally, the percent yield for the reaction is 82.56%.
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Solve the combined gas law problem
P₁ = 1.5 atm
V₁ = 3.0 L
T₁=20.0 °C
P2 = 2.5 atm
V₂ = ? L
T2 = 30.0 °C
Combined gas equation: P1V1/T1 = P2V2/T2
Solving for V2:
V2 = P1V1T2/P2T1
T1 = 20 °C = 293.15 K
T2 = 30 °C = 303.15 K
V2 = (1.5 × 3.0 × 303.15)/(2.5 × 293.15)
V2 = 1.86 L
what kind of intermolecular force is KI(aq)
Answer:
dipole-induced dipole forces
Explanation:
KI(aq) has potassium and iodine ions in water. Water is a polar molecule. So the type of force must be ion-dipole.
Which of the following is an aldehyde
What is the molar mass of unknown gas has a mass of 153 g and occupies 15 L at a temperature of 300 K and a pressure of 2 atm.
135 g/mol
17 g/mol
125 g/mol
160 g/mol
125 g/mol is the molar mass of unknown gas. Hence, option C is correct.
What is an ideal gas equation?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
First, calculate the moles of the gas using the gas law,
PV=nRT, where n is the moles and R is the gas constant. Then divide the given mass by the number of moles to get molar mass.
Given data:
P= 2 atm
V= 15 L
n=?
R= [tex]0.082057338 \;L \;atm \;K^{-1}mol^{-1}[/tex]
T=300 K
Putting value in the given equation:
[tex]\frac{PV}{RT}[/tex]=n
n= [tex]\frac{2 \;atm\; X \;15 \;L}{0.082057338 \;L \;atm \;K^{-1}mol^{-1} X 300}[/tex]
Moles = 1.21866 moles
Now,
Moles =[tex]\frac{mass}{molar \;mass}[/tex]
1.21866 =[tex]\frac{153 g}{molar \;mass}[/tex]
Molar mass= 125.54 mole/gram
125 g/mol is the molar mass of unknown gas. Hence, option C is correct.
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Which of these factors should remain constant in a simulation of natural
selection?
OA. The ratio of females to males
OB. The individuals observed
OC. The number of generations studied
OD. The population observed
SUBMIT
What can you determine about the feasibility of a reaction if the enthalpy is positive and
the entropy is positive?
A. The Gibbs energy will always be positive, and the reaction will never be feasible.
B. The Gibbs energy will always be negative, and the reaction will always be feasible.
OC. The reaction could be feasible above a certain temperature.
D. The reaction will usually occur because it is unlikely the entropy will be greater than the enthalpy.
Reset Selection
If the enthalpy is positive and the entropy is positive, the Gibbs energy will always be positive, and the reaction will never be feasible.
What is the Gibbs Free Energy?The Gibb Free Energy is used to obtain the feasibility of a reaction. If the Gibbs free energy is positive the reaction is not spontaneous. If the value is negative, the reaction is spontaneous while a zero values indicates equilibrium.
From the equation;
ΔG = ΔH - TΔS, it follows that if the enthalpy is positive and the entropy is positive, the Gibbs energy will always be positive, and the reaction will never be feasible.
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Which organisms reproduce through a...se...xu...al reproduction? (Select all that apply.)
starfish
yeast
fungi
bacteria
PICK MORE THAN ONE and no links please
Answer:
Bacteria by binary fission
Starfish
Fungi
Explanation:
[tex]\large{\underline{\underline{\pmb{\frak {\color {blue}{Answer:}}}}}}[/tex]
Organisms which apply binary fission are:
Starfish FungiBacteria[tex]\green\star[/tex]More things to learn about reproduction:
[tex]\blue\star[/tex]There are two modes of reproduction. They are:
Asèxual mode andSèxual modeAsèxual mode: The mode of reproduction where single parent is enough to give birth another organisms. Eg: Amoeba
Sèxual mode: The mode of reproduction where both parents, male and female are necessary. Eg: Human.
[tex] \boxed{ \frak \red{have \: a \: nice \: day}}[/tex]
Problems that I am stuck on! Need the answers asap
Answer:
1.b
2.b
3.a
4.a
Explanation:
use the rate laws when answering this.
How many moles of Unknown weak acid (HA) in a 100L solution are required to produce a solution with PH =2 ? Ka of the Unknown weak acid (HA)=5x10⁻³
a. 3x10⁻³
b. 0.3x10⁻³
c. 3
d. 0.3
The moles of unknown weak acid (HA) in a 100L solution are required to produce a solution with pH 2 is 0.002 moles.
What is the equation of the acid dissociation constant, Ka?The acid dissociation constant of an acid is given by the formula below:
[tex]K_a= \frac{[A^{-}][H_3O^{-}]}{[HA]}[/tex]
Where
Ka = 5x10⁻³ pH = 2[H3O+] = 10^-2Volume of solution = 100 mL or 0.1 LSince, the Ka is given at equilibrium concentrations, [H3O+] = [A-]
[A-] = 10^-2
Making [HA] subject of the formula:
[tex][HA]= \frac{[10^{-2}][10^{-2}]}{5 \times 10^{ - 3} } = 0.02[/tex]
Moles of acid = 0.1 × 0.02 = 0.002 moles
Therefore, the moles of unknown weak acid (HA) in a 100L solution are required to produce a solution with pH 2 is 0.002 moles.
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At what temperature would 0.46 moles of a gas occupy 13.3 L if the pressure is 734 mm Hg?
Answer: 341.6k
Explanation:
R= 0.0821
n= 0.46moles
v= 13.3L
p= 734mmhg = 734/760 = 0.97
[tex]T = \frac{p*v}{n*R}[/tex]
[tex]T = \frac{0.97*13.3}{0.46*0.0821}[/tex]
T= 341.6k
Answer:
10100101
Explanation:
this is for the other person alt.
Water and ammonia molecules are roughly the same size and the same mass but ammonia boils at -28F (-33C) and water boils at 212F (100C). What can we conclude about the intermolecular forces between water and ammonia?
We can infer that there are various intermolecular forces between water and ammonia.
The intensity of the intermolecular interactions between a substance's molecules affects its boiling point. Although water and ammonia have comparable molecular sizes and weights, their boiling points differ considerably. This implies that the intermolecular interactions between ammonia and water are different.
The powerful intermolecular force of hydrogen bonding causes water molecules to be drawn to one another. When the hydrogen atom of one water molecule is drawn to the oxygen atom of another water molecule, hydrogen bonding takes place.
As a result, the water molecules are held together by a web of intermolecular forces. These hydrogen bonds need a lot of energy to form. Consequently, water has a high boiling point.
On the other hand, dipole-dipole interactions between molecules occur between ammonia molecules. The nitrogen atom in the polar molecule ammonia (NH3) is more electronegative than the hydrogen atoms.
The hydrogen atoms are somewhat positively charged as a result of this polarity, while the nitrogen atoms are partially negatively charged. Ammonia has a lower boiling point because the dipole-dipole interactions between its molecules are less than the hydrogen bonds in water.
As a result, we can infer that the intensity of the intermolecular forces between water (hydrogen bonding) and ammonia (dipole-dipole interactions) differs based on the drastically different boiling temperatures of the two substances.
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Which sample contains more atoms:
3.89 g of nickel or 6.61 g of silver?
Defend your answer.
Select all the correct answers.
A red-hot iron nail is immersed in a large bucket of water. Although the nail cools down sufficiently to be held bare-handed, the temperature of the water barely increases. Which properties keep the water temperature from changing much?
The properties which keep the water temperature from changing much are;
water's high specific heat capacitythe large mass of waterWhat is specific heat capacity?The specific heat capacity is the property of a substance that shows how much its temperature changes when it is exposed to heat.
Thus, the properties which keep the water temperature from changing much are;
water's high specific heat capacitythe large mass of waterMissing parts:
A red-hot iron nail is immersed in a large bucket of water. Although the nail cools down sufficiently to be held bare-handed, the temperature of the water barely increases. Which properties keep the water temperature from changing much?
A.) water's high heat conductivity
B.) water's high specific heat capacity
C.) the iron nail's high heat conductivity
D.) the large mass of water
E.) the iron nail's high specific heat capacity
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Answer: waters high specific heat capacity the large mass of water
Explanation:
i got it right
Submit the answers to the checkpoint questions in the text box with the Lesson Review.
Part A Checkpoint
Directions: Complete each of the following questions.
(PICTURE FOR THE FIRST QUESTION)
1. Indicate the kind of energy represented in each example below:
a. Burning fuel in a car
b. Exploding an atomic bomb
c. Current moving in a wire
d. Tires sliding on pavement when brakes are applied
e. Football player running for a touchdown
2. All forms of energy except nuclear fission come from the _________.
3. Energy is ______________.
Energy is the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other forms.
The detonation of an atomic bomb releases enormous amounts of thermal energy, or heat, achieving temperatures of several million degrees in the exploding bomb itself. This thermal energy creates a large fireball, the heat of which can ignite ground fires that can incinerate an entire small city.
When the circuit is complete, there is a flow of charge (electric current). The electrons moving through the wire transfer energy to the wire in the form of heat. The particles in the wire, therefore, have more kinetic energy and so the temperature increases.
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Answer:ss
Explanation:ss
Is Hibiscus tea good for ACNE?
Answer:
Y E S
Explanation:
Hibiscus tea has plenty of skin care qualities, from helping your natural levels of collagen and elastin to reducing breakouts to balancing oil production. Hibiscus is known for its rich level of antioxidants, including vitamin C and beta-carotene.
I hope this helps ✍(◔◡◔)
If 33.9 ml of h3po4 neutralizes 23.4 ml of 2.28 m koh, what is the molarity of the phosphoric acid?
Answer: 1.57 M
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(33.9)M_{A}-=(23.4)(2.28)\\M_{A}=\frac{(23.4)(2.28)}{33.9}=\boxed{1.57 \text{ M}}[/tex]
In a mixture of oxygen and nitrogen, 80% of the gas pressure is exerted by the nitrogen. if the total pressure is 2.0 atm, what pressure does the oxygen exert?
0.4 atm pressure exerted by oxygen if 80% of the gas pressure is exerted by the nitrogen.
What is pressure?Pressure is defined to be the amount of force exerted per area
80% of pressure is exerted by nitrogen gas.
So, 20% of pressure will be exerted by oxygen gas.
20% of 2.0 atm = 0.4 atm
Hence, 0.4 atm pressure exerted by oxygen if 80% of the gas pressure is exerted by the nitrogen.
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What is a chemical property? Give an example.
Answer:
A chemical property example is fire.
Explanation:
Hope this helps!
Match the phase to the correct definition.
1.
Anaphase
2.
Prophase
3.
Metaphase
4.
Telophase
a.
Chromosomes line up at the center of the cell.
b.
The DNA is organized into connected rods called chromosomes.
c.
New cells begin to form.
d.
The chromosomes are separated and move to opposite sides of the cell.
Answer:
1.) Anaphase ------> D.) The chromosomes are separated and move to opposite sides of the cell.
2.) Prophase -------> B.) The DNA is organized into connected rods called chromosomes.
3.) Metaphase -------> A.) Chromosomes line up at the center of the cell.
4.) Telophase ------> C.) New cells begin to form.
list three properties of water that are related to hydrogen bonding
Current passes through a solution of sodium chloride. In 1. 00 second, 2. 68×1016na ions arrive at the negative electrode and 3. 92×1016cl− ions arrive at the positive electrode
The answer is the current passing between the electrodes is 10.56 mA., the direction of current is towards the negative electrode.
What is Electric Charge ?Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.
Electric charge can be positive or negative (commonly carried by protons and electrons respectively).
Like charges repel each other and unlike charges attract each other
Given that,
Number of sodium ions at the negative electrode, Na⁺ = 2.68 *10¹⁶
Number of chloride ions at the positive electrode,Cl⁻ = 3.92 *10¹⁶
(a) The current flowing in the circuit is due to the positive as well as negative charges such that total charge becomes:
Q= n e
Q = (Na⁺ +Cl⁻) e
Q= (2.68 *10¹⁶ +3.92 *10¹⁶) (1.6*10-19)
Q = 0.01056 C
The current is given by :
I=Q/t = 0.01056 /1 = 10.56mA
So, the current passing between the electrodes is 10.56 mA.
b) Since, positive ions are moving towards the negative electrode.
And, current is the flow of ions or electrons therefore, the direction of current is towards the negative electrode.
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The current is given by :
So, the current passing between the electrodes is 10.56 mA.
(b) The direction of electric current is towards negative electrodes.
Compare and contrast nuetrons,protons, and electrons
Calculate the molarity of a Ba(OH)2 solution if 1950 mL is completely titrated by 26.1 mL of 0.505 M HNO3
Answer: 0.01 M
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(26.1)(0.505)=(1950)M_{B}\\M_{B}=\frac{(26.1)(0.505)}{1950} \approx \boxed{0.01 \text{ M}}[/tex]