Answer:
pKa = 3.97
Explanation:
Let's state the equations:
NaA → A⁻ + Na⁺
A⁻ + H₂O ⇄ OH⁻ + HA Kb
We don't have the concentration of [OH⁻] but we do know pH, so we can determine, pOH and after that, [OH⁻].
14 - pH = pOH → 14 - 8.70 = 5.30
10^-pOH = [OH⁻] → 10⁻⁵'³⁰ = 5.01×10⁻⁶ M
Initially we can know, the moles of base, we had.
20 mL . 0.27M = 5.4 mmoles. So now, let's make the expression for Kb.
Kb = [OH⁻] . HA / [A⁻]
As the [OH⁻] is so low, we can assume, there where no loses and the salt is well concentrated. So:
Kb = (5.01×10⁻⁶)² / 0.27 → 9.29×10⁻¹¹
Kw = Ka . Kb, then Ka = Kw/ Kb
Ka = 1×10⁻¹⁴ /9.29×10⁻¹¹ = 1.08×10⁻⁴
pKa = - log Ka → - log 1.08×10⁻⁴ = 3.97
help please see attached file
Answer:
balanced equation of glucose
6CO2 + 6H2O----------C6H12O6 + 6O2
in the presence of sun light.
When calcium chloride is added to a sample of water, the boiling point will _________. A. increase B. decrease C. not change D. first decrease, then increase
Answer:
C
Explanation:
If you add salt to water, its boiling point increases.
When calcium chloride is added to a sample of water, the boiling point will increase. Option A is correct.
What is boiling point?The boiling point of the liquid is the temperature at which the vapor pressure of a given liquid equals the external pressure or atmospheric pressure surrounding the given liquid.
The calcium chloride is added to a sample of water it releases the some amount heat and become exothermic and the boiling point will increase due to the reaction of water and calcium chloride.
Therefore, when calcium chloride is added to a sample of water, the boiling point will increase. Option A is correct.
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When you straighten your leg, the muscles on top of your leg muscles on the bottom of your leg. Your answer
Answer:
your quad is the top part and your hamstring is the bottom part
Explanation:
fun fact the hamstring is one of the strongest muscles in the body
HELP 50 POINTS IF YOU DO IT RIGHT NOW
How much energy is released when 944.3 g of phosphoric acid is produced
P4O10(g) + 6H20(l) -- > 4H3PO4(aq)+424 kj
Answer:
1024.84 Kj
Explanation:
P₄o₁₀(g) + 6H₂O(l) => 4H₃PO₄(aq) + 424Kj
moles H₃PO₄ = (944.3g H₃PO₄) /(97.994g H₃PO₄ /mole H₃PO₄)
= 9.64 moles H₃PO₄
From equation reaction ratios ...
4 moles H₃PO₄ => 424 Kj
9.64 moles H₃PO₄ => (?)
4 moles H₃PO₄/9.64 moles H₃PO₄ = (424Kj)/(?)
Energy Released (Kj) = (424Kj)(9.64moles)/(4moles) = 1021.84 Kj
1, 2, or 3...help please
Answer:
molecular so number 3. ...
What are the products we get out of this
reaction? (check picture)
Explanation:
two compounds because element is the very smallest part of any mixture
A star's mass determines the A.length of its lifecycle b.location of the star c.galaxy it belongs to. D.shape of the star
Answer:
A.length of its lifecycle
Explanation:
A star will go through evolutionary stages depending on their initial mass. These stages are determined by the internal structure of the star and how it produces energy. Therefore, scientists may use the HR diagram to determine the length of the stars lifecycle depending upon its initial mass.
Which of the following elements would have the greatest attraction for
electrons? *
Rb
sr
Cs
Ba
Answer:
Sr
Explanation:
because it's electronegativity is the highest.
The temperature of a sample of gas in a steel tank at 60.0 kPa is increased from -105.0°C to 26.0
*C. What is the final pressure inside the tank?*
(
Answer:
106.785 kPa, I believe this is correct!
Explanation:
Balance the following equation
C₂H₆O + O₂ → CO₂ + H₂O
Answer:
C2H6O + 3O2 - > 2CO2 + 3H20
Which of the below will effect colligative properties the most?
Be3N2
OK₂S
CO
Mgs
Answer:
CO
Explanation:
How many atoms of hydrogen are in the compound 6(NH4)2CO3?
when Henry mosléy came up with he's own atomic number?
I WILL MARK AS BR*NLIST IF YOU CORRECT ANSWER
Answer:
1911 is when he made it
Explanation:
Moseley's law provided a reasonably complete experimental set of data that supported the (new from 1911) conception by Ernest Rutherford and Antonius van den Broek of the atom, with a positively charged nucleus surrounded by negatively charged electrons in which the atomic number is understood to be the exact physical number of positive charges (later discovered and called protons) in the central atomic nuclei of the elements.
How many spirals does a DNA molecule have?
Answer:
two
Explanation:
2
Answer:
two
Explanation:
nucleic acids are made up of chains of many repeating units called nucleotides. the dna molecule consists of two such chains that spiral around an imaginary axis to form a double helix (spiral.)
hope this helps :)
have a nice day !!
PLEASE ANSWER QUICKLYYY
At standard temperature and pressure one mole of H2 gas occupies
22.4 L. What is the volume occupied by 3.50 moles of H2?
Answer 78.4
Explanation:
Idfk calculations
2.00g of Copper wire was added to 50.0 mL of a 0.050M solution of Silver Nitrate. The reaction
produced solid silver and aqueous copper II Nitrate. The silver precipitate was collected and
dried. It was determined that the mass of the silver precipitate was 0.24 g. Use this information
to determine the theoretical yield, limiting reactant, and percent yield.
Answer:
See explanation
Explanation:
Now, the equation of the reaction is;
Cu(s) + 2AgNO3(aq) --------> Cu(NO3)3 (aq) + 2Ag(s)
Number of moles of silver precipitate = 0.24/108 g/mol= 0.0022 moles
Number of moles of AgNO3 = 50/1000 * 0.050 = 0.0025 Moles
If 2 moles of AgNO3 yields 2 moles of Ag
Then 0.0025 moles of AgNO3 yields 0.0025 * 2/2 = 0.0025 moles of Ag
Number of moles of Cu = 2.00g/63.5 g/mol = 0.03 moles
If 1 mole of Cu yields 2 moles of Ag
0.03 moles of Cu yields 0.03 moles * 2/1 = 0.06 moles of Ag
Hence AgNO3 is the limiting reactant
Theoretical yield of Ag = 0.0025 moles of Ag * 108 = 0.27 g
Actual yield of Ag = 0.24 g
Percent yield = actual yield/theoretical yield * 100
Percent yield = 0.24/0.27 * 100
Percent yield = 88.8%
You and a friend are swimming at your grandparent's house one toasty
summer afternoon. You have music playing through the Bluetooth speaker
on the pool deck, but every time you go underwater, you can hear the
noise, but you cannot understand the words of the song. What would
explain this phenomenon? *
Sound waves travel faster in a gas than they do in a liquid, which is why you cannot
understand the words,
Sound waves travel faster in a liquid than a gas, our ears are just not designed to
translate the faster moving waves,
Sound waves cannot travel at all in a liquid, which is why you cannot understand the
words and it's a miracle you can even hear the music at all,
Sound waves travel at the same speed regardless of the medium; your grandfather is
turning the music on and off when you go underwater and the noise you hear is the
song stuck in your head,
Answer:
Sound waves travel faster in a liquid than a gas, our ears are just not designed to translate the faster moving waves.
Explanation:
Sound waves are mechanical waves which travel through vibrating the medium (the "stuff") they're traveling through. This means they actually move faster through materials that are more dense, and will move more quickly through liquid than gas, and a solid than a liquid. However, our ears are adapted to "translating" sound waves in air rather than water, so we don't understand the music well when the waves move through the water.
A similar idea explains why our vision is blurry underwater; light waves travel at a different speed (slower, not faster!) in water and our eyes perceive this change in speed as blurriness.
According to periodic trends, at which position on the periodic table would
an element most likely have an electronegativity HIGHER than that of calcium?
Select ALL correct answers.
Answer:
Just to the right of calcium
Explanation:
Electronegativity increases as we go from left to right the periodic table
The image shows the mouth of a Tasmanian devil. The Tasmanian devil has four distinctive long teeth near the front of its mouth. Based on their shape, what are these teeth mostly like used for?
A.
holding and tearing meat
B.
crunching and crushing bone
C.
grinding up plant material
D.
rooting in soil for worms
Answer:
same as the answer of her
Explanation:
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A mixture of four gases exerts a total pressure of 960
mm Hg. Gase A each exert 120 mm Hg. Gas B exerts
50 mm Hg. What pressure is exerted by gas C?
Omitted question:I think you mean Gas A and D each exert 120 mm Hg, if Gas D has a different value , just lug it into he equation as shown below and solve.
Answer:Gas C= 670mmHg
Explanation:
According to Dalton law of partial pressure
The total pressure of a mixture of gases is the sum of the pressures of each gas and can be illustrated as
Pressure total=P1+P2+… +Pn.
Total Pressure = Gas A + Gas B + Gas C + Gas D + Gas...
Now we have
Total Pressure = 120 mm Hg + 50mm Hg + Gas C + 120 mm Hg
960mmHg = 120 mm Hg + 50mm Hg + Gas C + 120 mm Hg
960mmHg =290mmHg +Gas C
Gas C =960mmHg -290mmHg
Gas C= 670mmHg
The reaction is carried out at a high temperature to provide the reactant with activation energy.what is activation energy?
Answer:
Activation energy, in chemistry, the minimum amount of energy that is required to activate atoms or molecules to a condition in which they can undergo a chemical transformation or physical transport.
The measured pOH of a solution is 5.5. What is the hydrogen ion, [H+ ],
concentration?
First, calculate pH using the pOH:
14 - pOH = pH --> pH = 14 - 5.5 = 9.5
[H+] = 10^-pH = 10^-9.5 = 3.2 x 10^-10 M ≈ 3 x 10^-10 M (The answer should technically only be one sig fig, since the pOH is given to only one decimal place).
3.) 2.46 grams of Cu(NO3)2 would contain how many formula units?
Answer:
7.90×10²¹ formula units
Explanation:
From the question given above, the following data were obtained:
Mass of Cu(NO₃)₂ = 2.46 g
Formula units of Cu(NO₃)₂ =?
From Avogadro's hypothesis,
1 mole of Cu(NO₃)₂ = 6.02×10²³ formula units
Next, we shall determine the mass of 1 mole of Cu(NO₃)₂. This can be obtained as follow:
1 mole of Cu(NO₃)₂ = 63.5 + 2[14 + (3×16)]
= 63.5 + 2[14 + 48]
= 63.5 + 2[62]
= 63.5 + 124
= 187.5 g
Thus,
187.5 g of Cu(NO₃)₂ = 6.02×10²³ formula units
Finally, we shall determine the formula units contained in 2.46 g of Cu(NO₃)₂. This can be obtained as follow:
187.5 g of Cu(NO₃)₂ = 6.02×10²³ formula units.
Therefore,
2.46 g of Cu(NO₃)₂ =
(2.46 × 6.02×10²³)/187.5
= 7.90×10²¹ formula units
Thus, 2.46 g of Cu(NO₃)₂ contains 7.90×10²¹ formula units
The urinary bladder is a muscular organ of the excretory system that collects urine excreted by the kidney. How does the nervous system help the urinary system in excretion?
Explanation:
it helps in when the kidney has used the needful nutrients been taken then the unwanted waste product it sends it to the nervous system then the nervous system passes the waste product to the bladder in form of urine
a tiny particle in the nucleus of an atom that is about the same size as a proton is a(n)
A. electron
B. neutron
C. solid
D. element
Answer:
b. neutron.
Explanation:
I hope this helps.
Answer:
B. Neutron
Explanation:
Neutrons are about the same size as protons. In addition, nuclei are made up of neutrons and protons. Electrons are located in the electron cloud, which is outside of the nucleus. Solids are hard matter, and an element is a substance that cannot be broken down any further.
Hope this helps!
How do living things (such as animals) affect the phosphorus cycle?
Explanation:
Phosphorus moves in a circle through rocks, water, soil and sediments and organisms. Over time, rain and weathering cause rocks to release phosphate ions and other minerals.What is the scientific method? *
a. A series of steps used by scientists to investigate an hypothesis
b. A series of steps used to determine which chemicals are good for use
c. A series of steps used to tell how life began on earth
d. A series of steps used to by scientists to find about technology
4) How many liters are needed for a 5.1 Molar solution containing 2.3 moles of NaCl?
moles =
Molarity =
Liters =
Why are halogens unreactive?
A. *Halogens need one to two more electrons to fill their outer shell.
B. Halogens need three to four more electrons to fill their outer shell.
C. D. Halogens have a full outer shell of valence electrons.
Answer: B) is the answer.
Explanation:
What does the reaction rate say about a reaction?
O It tells what activation energy the reaction has.
O It tells if a catalyst was used in the reaction.
It tells how quickly products will be made.
It tells what the concentration of reactants is.
Previous
Answer:
It tells how quickly products will be made.
Explanation:
ap3
x
The reaction rate provides information about how quickly products will be made in a chemical reaction.
The reaction rate is a measure of how fast a chemical reaction proceeds over time. It provides information about the speed at which reactants are consumed and products are formed during a reaction. The reaction rate is typically expressed as the change in concentration of a reactant or product per unit of time.
The reaction rate is influenced by various factors such as the nature of the reactants, concentration of reactants, temperature, surface area, and the presence of catalysts. By measuring the reaction rate, scientists can gain insights into the kinetics of a reaction and understand the factors that affect its speed.
The reaction rate is particularly important because it allows us to predict and control the rate at which products are formed. It is useful in various applications, including industrial processes, pharmaceutical development, and environmental studies. By manipulating the reaction conditions, such as adjusting the concentration of reactants or introducing a catalyst, we can alter the reaction rate to achieve desired outcomes.
In summary, the reaction rate provides valuable information about the speed at which products are formed in a chemical reaction, allowing us to understand and control the kinetics of the process.
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