Answer: Ba(NO3)2(aq) + H2O(l)
Explanation:
7. Which of the following is a proof that light travels in a straight line?
A. Formation of clouds
C. Formation of rainbows
B. Formation of colors
D. Formation of shadow
Answer:
formation of shadow is right
Answer:
correct answer is D
Explanation:
When you see a shadow, it is directly behind the object.
100.00 mL of 0.15 M nitrous acid (HNO2) are titrated with a 0.15 M NaOH solution. (a) Calculate the pH for the initial solution. (b) Calculate the pH for the point at which 80.0 mL of the base has been added. (c) Calculate the pH for the equivalence point. (d) Calculate the pH for the point at which 105 mL of the base has been added.
Answer:
a. pH = 2.04
b. pH = 3.85
c. pH = 8.06
d. pH = 11.56
Explanation:
The nitrous acid is a weak acid (Ka = 5.6x10⁻⁴) that reacts with NaOH as follows:
HNO₂ + NaOH → NaNO₂(aq) + H₂O(l)
a. At the beginning there is just a solution of 0.12M HNO₂. As Ka is:
Ka = [H⁺] [NO₂⁻] / [HNO₂]
Where [H⁺] and [NO₂⁻] ions comes from the same equilibrium ([H⁺] = [NO₂⁻] = X):
5.6x10⁻⁴ = X² / 0.15M
8.4x10⁻⁵ = X²
X = [H⁺] = 9.165x10⁻³M
As pH = -log [H⁺]
pH = 2.04b. At this point we have HNO₂ and NaNO₂ (The weak acid and the conjugate base), a buffer. The pH of a buffer is obtained using H-H equation:
pH = pKa + log [NaNO₂] / [HNO₂]
Where pH is the pH of the buffer,
pKa is -log Ka = 3.25
And [NaNO₂] [HNO₂] could be taken as the moles of each compound.
The initial moles of HNO₂ are:
0.100L * (0.15mol / L) = 0.015moles
The moles of base added are:
0.0800L * (0.15mol / L) = 0.012moles
The moles of base added = Moles of NaNO₂ produced = 0.012moles.
And the moles of HNO₂ that remains are:
0.015moles - 0.012moles = 0.003moles
Replacing in H-H equation:
pH = 3.25 + log [0.012moles] / [0.003moles]
pH = 3.85c. At equivalence point all HNO2 reacts producing NaNO₂. The volume added of NaOH must be 100mL. That means the concentration of the NaNO₂ is:
0.15M / 2 = 0.075M
The NaNO₂ is in equilibrium with water as follows:
NaNO₂(aq) + H₂O(l) ⇄ HNO₂(aq) + OH⁻(aq) + Na⁺
The equilibrium constant, kb, is:
Kb = Kw/Ka = 1x10⁻¹⁴ / 5.6x10⁻⁴ = 1.79x10⁻¹¹ = [OH⁻] [HNO₂] / [NaNO₂]
Where [OH⁻] = [HNO₂] = x
[NaNO₂] = 0.075M
1.79x10⁻¹¹ = [X] [X] / [0.075M]
1.34x10⁻¹² = X²
X = 1.16x10⁻⁶M = [OH⁻]
pOH = -log [OH-] = 5.94
pH = 14-pOH
pH = 8.06d. At this point, 5mL of NaOH are added in excess, the moles are:
5mL = 5x10⁻³L * (0.15mol / L) =7.5x10⁻⁴moles NaOH
In 100mL + 105mL = 205mL = 0.205L. [NaOH] = 7.5x10⁻⁴moles NaOH / 0.205L =
3.66x10⁻³M = [OH⁻]
pOH = 2.44
pH = 14 - pOH
pH = 11.56
Why are half-reactions used in redox reactions?
Answer:
Because a redox reaction holds for both oxidation and reduction.
One half equation is of oxidation and the other is of reduction.
When these two half equations are combined, we get an overall equation of the redox reaction.
3.88g of NaOH is required to neutralize a spill of hydrochloric acid. A 0.516M solution of NaOH is available for use.
A. Determine the number of moles needed to complete the reaction.
B. What volume of NaOH solution is needed for this reaction?
C. What volume of a stock 1,15M solution would be used to make the solution used in the reaction?
Answer:
ftb
Explanation:
How is water used in society
Answer:
Water can be used for direct and indirect purposes. Direct purposes include bathing, drinking, and cooking, while examples of indirect purposes are the use of water in processing wood to make paper and in producing steel for automobiles. The bulk of the world's water use is for agriculture, industry, and electricity.
Explanation:
Answer:
water is used for drinking, bathing, cooking, agriculture etc
Put the steps of the carbon cycle in order using Step 1 as your starting point.
Step 1: Bacteria, through nitrogen fixation and nitrification, convert nitrogen into a usable form.
The animal dies and decomposes, returning nitrogen back to the soil.
Once nitrogen is in usable form, it is taken up by plants and assimilated into proteins..
An animal eats a plant and the nitrogen becomes part of the animal’s proteins.
Answer:
Carbon moves from the atmosphere to plants. ...
Carbon moves from plants to animals. ...
Carbon moves from plants and animals to soils. ...
Carbon moves from living things to the atmosphere. ...
Carbon moves from fossil fuels to the atmosphere when fuels are burned. ...
Carbon moves from the atmosphere to the oceans.
Explanation:
Answer:
step 4 , 2 , 3
Explanation:
In the process of photosynthesis, sunlight is converted into
Answer:
Chemical energy
Explanation:
By the use of electrons and protons from water
Answer:
chemical energy
Explanation:
Photosynthesis is the process by which organisms that contain the pigment chlorophyll convert light energy into chemical energy which can be stored in the molecular bonds of organic molecules (e.g., sugars). Photosynthesis powers almost all trophic chains and food webs on the Earth.
A mixture of NO2 and N2O4 gas is at equilibrium in a closed container. These gases react with the equation 2NO2 ⇌ N2O4. What will happen if the size of the container is increased?
Answer:
Equilibrium will shift leftwards towards NO2.
Explanation:
Hello there!
In this case, according to the Le Cha telier's principle, it is possible to realize that the increase of the volume turns out in the shift towards the most of the gaseous moles are in; in such a way, for the given chemical reaction, we can notice how NO2 (reactant side) has the most of the moles (2 moles in comparison to 1 mole of N2O4); and therefore, by increasing the volume, the equilibrium will shift to it, it means leftwards.
Best regards!
Please Need help asap
For Al, its atomic number is 13 and its mass number is 27. How many neutrons does it have?
А. 13
B. 14
C. 26
D. 27
E. 40
Answer:
A
Explanation:
The number of protons and neutrons of an element is the same. the electrons are the only thing that can differ. The atomic number equal the protons and neutrons.
Which of the following astronomical bodies would most likely be the largest?
1. A dwarf star from a nearby solar system
2. A comet
3. One of the gas giants in our solar system
4. Ganymede, the largest moon of Jupiter
Answer:
1
because a dwarf star will seemlarge because of the in ability of any human being to see d sun
Help hurry please !!!!!
A wave travels at 22 m/s and has a wavelength of 11 m. What is its frequency
The answer is 2Hz
To calculate frequency, divide the number of times the event occurs by the length of time.
Explain in detail how low density polyethylene is made
Answer:
Low-density polyethylene is manufactured by the process of the polymerization of ethylene at very high temperatures in a tubular reactor. In this tubular reactor, high-pressure polymerization allows further copolymerization of ethylene with polar co-monomers. The tubular process has an advantage over autoclave process.
Explanation:
please mark brainliest
Calculate the enthalpy change for the photosynthesis of gluclose
Answer:
jhdgafhgafhagfhafg
Explanation:
Ali says the climate of a town is rainy because it is raining outside today. Is she correct? In one or two sentences, explain why Ali is or is not correct about the climate of the town.
Answer:
Ali is incorrect.
Explanation:
Ali is wrong because the climate is a study of the weather pattern over a long period of time. You cannot look outside one day and determine the climate because the climate is long-term.
She could say the weather is rainy, because that is short term, but not the climate.
3.
The color of the powdered form of a mineral is called
O fracture
O cleavage
O luster
O streak
Answer:
D. Streak.
Explanation:
A mineral, in simple terms, can be defined as a solid inorganic substance that occurs in a pure form with a specific crystal structure. A mineral is identified based on its physical properties which include luster, color, streak, crystal shape, etc.
The color of the powdered form of a mineral is called a streak. A streak is a useful property in distinguishing sulfide and oxide minerals. To check the color of a mineral, it is rubbed against the surface of a ceramic streak plate or a piece of unglazed ceramic. In its finely powdered form, a mineral is easy to identify.
Therefore, option D is correct.
There is a bottle of KCl solution: the volume is 35 mL; its molarity is 3.0 M.
After diluting it into final volume 200 mL, what is the molarity (in M) now?
Answer:
0.525 M
Explanation:
As the problem deals with a dilution process, we can use the following formula:
C₁V₁=C₂V₂Where subscript 1 stands for initial concentration and volume, while 2 stands for the final conditions. Meaning that in this case:
C₁ = 3.0 MV₁ = 35 mLC₂ = ?V₂ = 200 mLWe input the data given by the problem:
3.0 M * 35 mL = C₂ * 200 mLAnd solve for C₂:
C₂ = 0.525 MA coffee cup calorimeter will not be used to
directly measure the enthalpy of magnesium
combustion because
✓ the coffee cups could melt.
The calorimeter is made of coffee cups instead of
a beaker because coffee cups are
✓ better insulators
than beakers.
You will not measure the enthalpy of the reaction
of
✓ H2 and 02
in the coffee cup calorimeter because this reaction involves gases
Instead, you will use a well-known published
value.
These are the correct answers on edge 2021
Answer:
Ingles porfavor
Explanation:
The calorimeter is used to measure the heat of the system. The enthalpy of the combustion of magnesium cannot be measured by the calorimeter as it could melt the cup.
What is a coffee cup calorimeter?A coffee cup calorimeter is a styrofoam cup that contains partially filled water and is dipped with a thermometer. The reaction occurs in the water of the cup and hence differs from the bomb calorimeter.
The enthalpy of combustion is rigorous which can dissolve the polystyrene cup and hence is not used. They are better insulators than a beaker. The coffee cup calorimeter is not used to measure the enthalpy of hydrogen and oxygen as they involve gases that can escape the cup.
Learn more about coffee cup calorimeter here:
https://brainly.com/question/4390364
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What is the energy of an electron in a Li+ ion when an electron moves from n = 2 to n =3?
Psychology is the study of the human brain. A psychoanalyst is a person who
analyzes people's minds. What does the prefix psycho-mean?
A. Related to the brain
B. Related to studying
C. Related to science
D. Related to analysis
A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is ________ M. A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is ________ M. 0.150 0.234 0.300 0.469 0.938
Answer: The concentration of [tex]H_2SO_4[/tex] is 0.234 M
Explanation:
According to the neutralization law,
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1[/tex] = basicity [tex]H_2SO_4[/tex] = 2
[tex]M_1[/tex] = molarity of [tex]H_2SO_4[/tex] solution = ?
[tex]V_1[/tex] = volume of [tex]H_2SO_4[/tex] solution = 50.0 ml
[tex]n_2[/tex] = acidity of [tex]NaOH[/tex] = 1
[tex]M_1[/tex] = molarity of [tex]NaOH[/tex] solution = 0.375 M
[tex]V_1[/tex] = volume of [tex]NaOH[/tex] solution = 62.5 ml
Putting in the values we get:
[tex]2\times M_1\times 50.0=1\times 0.375\times 62.5[/tex]
[tex]M_1=0.234M[/tex]
Therefore concentration of [tex]H_2SO_4[/tex] is 0.234 M
Iodine shines like metals but is not metal what is its basis
Answer:
Iodine is a non-metal, but it is lustrous (lustrous is the property of metal) in nature.
Do not abuse or misuse any piece of drawing instrument. ASAPPPP
What is the molar mass of AlCl3
Answer:
133.34 g/moles
Explanation:
but to make life easy it could be 133.4 g/ moles as well
Is anyone good at chemistry if so can someone help me please ?
(NO LINKS)
Question 15
We're given the [OH⁻] as 8.34 × 10⁻¹² M. Using the formula pOH = -log[OH⁻], the pOH of this solution would be -log(8.34 × 10⁻¹²) ≈ 11.08.
The pOH is, for lack of a better term, the "opposite" of pH: A pOH of 7 is neutral; a pOH less than 7 is basic; and a pOH greater than 7 is acidic.
This follows from the relation, pH + pOH = 14. In this case, with a pOH of 11.08, our pH would be 14 - 11.08 = 2.92, which is acidic (pH < 7).
Thus, the correct answer choice is B.
Q3: Match the column A with Column B and write answer in Column C
Answer:
ok
Explanation:
1d
2c
3b
4a
How many mL of 0.100M Ca(OH) are needed to titrate 20.0mL of 0.300M H2SO4
Answer:
60.0 mL
Explanation:
Using CAVA = CBVB
CA = 0.300M
VA = 20.0 mL
CB = 0.100M
VB = ?
VB = CAVA
CB
VB = 0.300 * 20/ 0.100
VB = 60.0 mL
explain what is ment by solvent front
Answer:
In paper chromatography, the wet moving edge of the solvent that progresses along the surface where the separation of the mixture is occurring.
Explanation:
I hope this helps and pls mark me brainliest :)
What would
happen to the
vultures if the
gazelle
decreased?
Answer: If the gazelle population starts to decrease this could lead to some vultures not having enough food to eat
Explanation: This explains the obvious outcome of what would happen.
Hope you do well with what your doing :)
Mark as Brainliest please :)
Worth 100 points plus ill mark brainliest
How many grams of sodium phosphate ( Na₃PO₄ )are required to make 125 milliliters of a 0.240 Molar solution?
4.92
6.48
8.44
12.5
Answer:
4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.
Explanation:
Molarity is a measure of concentration that indicates the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:
[tex]Molarity=\frac{number of moles}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
In this case:
Molarity= 0.240 Mnumber of moles= ?volume= 125 mL= 0.125 LReplacing in the definition of molarity:
[tex]0.240 M=\frac{number of moles}{0.125 L}[/tex]
Solving:
number of moles= 0.240 M*0.125 L
number of moles= 0.03 moles
Being the molar mass of sodium phosphate 164 g/mole, that is, the mass of one mole of the compound, you can calculate the mass of 0.03 moles using the following rule of three: if 1 mole of the compound has 164 grams, 0.03 moles contains how much mass?
[tex]mass=\frac{0.03 moles*164 grams}{1 mole}[/tex]
mass= 4.92 grams
4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.
