Answer: it’s D
Explanation:an event that provokes a specific functional response in an organ or tissue of an organism is called as stimulus
hope it helps
Caffeine (C8H10N4O2) is a weak base with a pKb of 10.4. Calculate the pH of a solution containing a caffeine concentration of 415 mg/L .
Answer:
pH → 7.47
Explanation:
Caffeine is a sort of amine, which is a weak base. Then, this pH should be higher than 7.
Caffeine + H₂O ⇄ Caffeine⁺ + OH⁻ Kb
1 mol of caffeine in water can give hydroxides and protonated caffeine.
We convert the concentration from mg/L to M
415 mg = 0.415 g
0.415 g / 194.19 g/mol = 2.14×10⁻³ mol
[Caffeine] = 2.14×10⁻³ M
Let's calculate pH. As we don't have Kb, we can obtain it from pKb.
- log Kb = pKb → 10^-pKb = Kb
10⁻¹⁰'⁴ = 3.98×10⁻¹¹
We go to equilibrium:
Caffeine + H₂O ⇄ Caffeine⁺ + OH⁻ Kb
Initially we have 2.14×10⁻³ moles of caffeine, so, after the equilibrium we may have (2.14×10⁻³ - x)
X will be the amount of protonated caffeine and OH⁻
Caffeine + H₂O ⇄ Caffeine⁺ + OH⁻ Kb
(2.14×10⁻³ - x) x x
We make the expression for Kb:
3.98×10⁻¹¹ = x² / (2.14×10⁻³ - x)
We can missed the -x in denominator, because Kb it's a very small value.
So: 3.98×10⁻¹¹ = x² / 2.14×10⁻³
√(3.98×10⁻¹¹ . 2.14×10⁻³) = x → 2.92×10⁻⁷
That's the [OH⁻]. - log [OH⁻] = pOH
- log 2.92×10⁻⁷ = 6.53 → pOH
14 - pOH = pH → 14 - 6.53 = 7.47
Just a curious question to the Chemists,
If you were to 'accidentally' discover something through a chemical reaction that could change the world, what would it be and what positive impact would it have on society?
Answer:
well the world would be shocked
Explanation:
and suprise
Two containers, illustrated below, are filled with the same amount and the same kind of ideal gas.
Which statement correctly describes the relationship between the contents of the two containers?
Container 1 particles have higher average kinetic energy and higher temperature than Container 2 particles.
Container 1 particles have lower average kinetic energy and lower temperature than Container 2 particles.
Container 1 particles have lower average kinetic energy and lower temperature than Container 2 particles.
Container 1 particles have lower average kinetic energy and higher temperature than Container 2 particles.
Container 1 particles have lower average kinetic energy and higher temperature than Container 2 particles.
Container 1 and Container 2 particles have the same average kinetic energy and the same temperature.
Container 1 and Container 2 particles have the same average kinetic energy and the same temperature.
Answer:
Container 1 particles have lower average kinetic energy and higher temperature than Container 2 particles.
Explanation:
Kinetic energy is the speed of the particles in the bottle.
As you can see in the illustration below, the patricles in Picture 2 are moving faster than the ones in Picture 1.
The tempature of Container 1 is higher because all of the particles are sitting on top of one another. Not being able to move, their pressure builds up and creates heat.
How does molecular shake affect polarity?
Answer:
I believe its A
Explanation:
A molecule that has a symmetrical shape will be a nonpolar molecule.
how many daughter cells would be produced if 32 cells undergo meiosis
Answer:
The meiosis process can for up to 4 daughter cells
if i want to make 14 moles of potassium chloride, how many grams of potassium do i need? Show all work. Make sure to include unit and substance
Answer:
The answer is 0.013413582325191. i assume you are converting between moles Potassium Chloride and gram. The molecular formula for Potassium Chloride is KCl. The SI base unit for amount of substance is the mole. 1 mole is equal to 1 moles Potassium Chloride, or 74.5513 grams.
Explanation:
A model is simplified version of a more complex idea or system. It useful to help us understand something we can't actually see
A) true
B) false
Answer:
I feel like the answer is A) true
Explanation:
you create a model to help your audience understand your complex idea. There have been models made to represent ideas that we cannot see.
How many molecules are in 3 moles of NaCl?
Answer:
Given : No. Of moles = 1.5
To calculate : no. Of molecules =N
We know that moles = N / 6.022 x 10²³
Therefore, 1.5 x 6.022 x 10²³ = N
Hence N = 9.0330x 10²³ molecules
5. The pictures below show four kinds of seeds. Which seed has a structure that
allows it to be carried away by wind?
A Bean seed
B Watermelon seed
C Dandelion seed
D Acorn
Answer:
Dandelion seed
Explanation:
(I learnt it in camp)
Answer:
C Dandelion Seed
Explanation:
Dandelion Seed are light enough to be carried by the wind.
1. Three fluids are poured from a beaker onto a lab table. Fluid A hits the table in 10 seconds, fluid B in 12 seconds, fluid C in 4 seconds, and fluid D
in 15 seconds. Which fluid has the highest viscosity?
O a fluid A
O b. fluid B
O c. fluid c
O d. fluid D
Answer:
fluid D
Explanation:
Fluid D has the highest viscosity because it is more difficult for it to move which makes it hit the table at 15 seconds
while fluid C has the lowest Viscocity which makes it move easily and it hit the table fastest
How many moles would there be in 500,000,000,000 atoms of silver? Show your calculation
and answer in unit
Answer:
Answer: 3.01 * 10^35
Explanation:
500,000,000,000 * 6.02 * 10^23
A student adds 5400.0mL of 0.15M NaOH to 201.2mL of 4.0M NaOH. What is the final [NaOH]?
Answer:
0.287 M
Explanation:
Multiply the concentration of each solution by the volume of each (in liters) to get the moles of NaOH in that solution.
0.15 M • 5.4000 L = 0.81 mol NaOH
4.0 M • 0.2012 L = 0.80 mol NaOH
Add the mol of NaOH together to get the total --> 0.81 + 0.80 = 1.61 mol NaOH
Divide by the total volume of solution (5400.0 mL + 201.2 mL = 5,601.2 mL = 5.6012 L)
1.61 mol / 5.6012 L = 0.287 M NaOH
What is the name
of the reigning
theory about the
origins of the
universe?
Answer:
please follow me
Explanation:
eyye6ww6yeyosuyoyo6owy
A sample of gas at 300k has a volume of 2 liters at what temperature will the volume decrease to 1 liter if the pressure is kept constant
Answer:PV=nRT ideal gas law
P presdure
V volume
n number of moles of gas
R gas constant
T temperature
Explanation: V=nRT/P
2liters=nR300k/P
divide by 2 for the equation
1liters=nR150k/P
with nR remaining constant
Water (H2O) is a polar molecule. Ethane (C2H6) is nonpolar.
What is true about water and ethane?
Ethane is likely to have a higher boiling point because it is nonpolar.
Ethane is likely to have a higher boiling point because it has fewer atoms per molecule.
Water is likely to have a higher boiling point because it has fewer atoms per molecule.
Statement which is true about ethane and water is that water is likely to have a higher boiling point because it has fewer atoms per molecule.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
Learn more about atom,here:
https://brainly.com/question/13654549
#SPJ2
In test tube 3, 3 mL of .002 M Fe(III) solution is combined with 7 mL of .02 M 5-sulfosaliclic acid (SSA) solution. What is the mole fraction of SSA in the test tube
Answer:
0.96
Explanation:
Number of moles of Fe(III) = 3/1000 * 0.002 M = 6 * 10^-6 moles
Number of moles of SSA = 7/1000 * 0.02 = 1.4 * 10^-4 moles
Total number of moles = 6 * 10^-6 moles + 1.4 * 10^-4 moles
Mole fraction of SSA = number of moles of SSA/ total number of moles.
Mole fraction of SSA = 1.4 * 10^-4 moles/ 6 * 10^-6 moles + 1.4 * 10^-4 moles
Mole fraction of SSA = 0.96
What are the four organelles that process, transport, and stone materials?ANSWER QUICK PLZZ no website
Toma en cuenta los textos para responder estas interrogantes: ¿Consideramos que la aplicación de las medidas de seguridad depende de las características de tu entorno?
Answer:
Si.
Explicación:
Sí, la aplicación de medidas de seguridad depende de las características de su entorno porque el entorno nos brinda para elegir las medidas de seguridad. Existen diferentes instrumentos utilizados para la seguridad de diferentes entornos. Algunas medidas de seguridad se aplican en un entorno mientras que el otro se aplica a otro entorno. Por ejemplo, el vallado es una medida de seguridad que se puede aplicar en el terreno pero no en el agua o cualquier zona fangosa, por lo que podemos decir que las características físicas deciden qué medida de seguridad se debe instalar en el entorno.
A building is found to be losing heat to the outside during the winter months. Which would be the best solution to correct this design problem?
increase amount of heating
increase surface area of walls
increase number of windows
increase thickness of insulation
no link or I will report
Answer:
increase thickness of insulation
Explanation:
don't increase amount of heating because that's difficult and not efficient.
don't increase surface area of walls because that makes heat be lost quicker.
don't increase windows because windows lose heat worse than walls.
increase thickness of insulation because it's the most effiecient and effective method of keeping heat.
What is the pH of a solution that has [H+] of .0042M?
Answer:
pH = 2.4
Explanation:
pH is defined as the negative log of the hydronium concentration.
Thus, we can plug in the given hydronium concentration:
pH = -log[H⁺] = -log[0.0042] = 2.4 (two significant figures)
The pH of the solution is 2.4.
P.S: Although I referred to [H⁺] as hydronium concentration, it is more accurate to express it as [H₃O⁺], though they are interchangeable and means the same thing.
350.0 ML of air is at 23.0°C what is the volume at 90.0°C
Answer:
V=0.430 Liters
Explanation:
First off you need to convert ml to l and celsius to kelvin, in order for them to be in the S.I.
So, 350.0mL is 0.350 L and 23.0 C is (273.15+23=) 296.15 K (you can ignore the 0.15)
From the equation pV=nRT, lets name this equation (1), we can tell that the number of moles, pressure, and R, stay the same. The only thing changing is the volume, and temperature.
With the information given, let's figure out the pressure. From equation (1) if we solve it for the pressure of the gas, p=nRT/V => p=nR*296.15/0.350 => p=846.15 *nR
Now, we have to figure out the volume of the gas at 90.0 C (363.15 K), and solve equation (1) for volume, using the pressure we previously found.
v=nRT/p => v=nR*363.15/846.15*nR => (the nR's from top and bottom go away) v=0.429 L
Since we used 273.15 for the conversion of celsius to Kelvin, we could round up the number to
V=0.430 Liters
What is the mass in grams of 3.75 × 10 21 atoms of Li?
Answer:
The mass
Explanation:
the mass grams of 3.75 × 10 21 atoms of Li is
40. 21 atom of Li
A swimmer pushes against a wall with his feet, as shown below.
The wall pushes back against the swimmer's feet with the same force. Which of Newton's laws does this best demonstrate?
A.
Newton's law of universal gravitation
B.
Newton's second law of motion
C.
Newton's third law of motion
D.
Newton's first law of motion
Answer:
C. newton's third law of motion
Explanation:
as newton's third law of motion states that every action has a reaction that is equal in size, opposite in direction, and acts simultaneously.
Pt2 science......
Select correct answer ♡!
Balance the following equation: Fe2O3 + H2O --> Fe(OH)3
A.3,2,1
B.2,2,3
C.1,3,2
D.5,2,10
Answer:
answer is c
Explanation:
hope it helps!!!
1. Long strands of DNA that contain lots of genes
A. Allele
B. Inherited Trait
C. Gene
D. Chromosome
Answer: chromosome
Explanation: :)
Pt4 science......
Select correct answer ♡ !
a substance made up of only atoms of one type is called
Answer: chemical element
Explanation: A chemical element is a substance that contains only one type of atom, which is the smallest particle of an element.
Iron(II) sulfide +
potassium—> makes what ?
Answer:
Potassium Sulfide
Explanation:
K is more reactive than Fe which means K displaces Fe from the equation
It take 38.70cm³ of 1.90 NaO4 to neutralize 10.30cm³ of H2So4 in a battery. Calculate the molar concentration of H2So4
Answer:
The molar concentration of base Cb = 14.2777M
Explanation:
Volume of acid Va = 38.70cm^3,
Concentration of acid NaO4 C_a= 1.90M
Volume of Base Vb = 10.30cm^3
Also, Equation of the reaction
H2SO4 + 2NaOH = Na2SO4 + 2H2O
No of mole of acid Na = 1
No of mole of base Nb = 2
CaVa/CbVb = Na/Nb
Cb = CaVaNb/VbNa
Cb = 1.9×38.7×2/(10.30×1)
Therefore, Cb = 14.2777M
The molar concentration of base Cb = 14.2777M
