Answer:
938.54 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question
[tex]n = \frac{5.65 \times {10}^{26} }{6.02 \times {10}^{23} } \\ = 938.5382[/tex]
We have the final answer as
938.54 molesHope this helps you
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 = 11.56How 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
Which of the following is the correct definition for electronegativity?
А. The amount of energy to attract or bond electrons
В. The amount of energy required to remove an electron
C. Half the distance between the nuclei of two bonded atoms
D. All of the above correctly explain electronegativity
Answer:
[tex]\color{Blue}\huge\boxed{Question} [/tex]
Which of the following is the correct definition for electronegativity[tex]\color{Blue}\huge\boxed{Answer} [/tex]
А. The amount of energy to attract or bond electronsWhich of these is most likely made of pieces of rock that are weathered by water and wind?
O A diamonds
OB sand
OC grass
OD vegetables
Answer:
The answer would be sand.
Explanation:
Sand is weathered down tiny pieces of rock. Sand flows down rivers to shores and slowly builds up to form beaches.
Answer:
The Answer is gonna be B sand
What needs to be taken into consideration when increasing either the acid or base concentration in order to increase the buffering capacity of a solution?
The more concentrated the buffer solution, the greater its buffer capacity.
What is an acid?An acid is any substance that in water solution tastes sour, changes blue litmus paper to red, reacts with some metals to liberate hydrogen, reacts with bases to form salts, and promotes chemical reactions.
The more concentrated the buffer solution, the greater its buffer capacity.
If the buffer capacity is 10 times larger, then the buffer solution can absorb 10 times more strong acid or base before undergoing a significant change in pH.
Hence, we need to take this into consideration when increasing either the acid or base concentration in order to increase the buffering capacity of a solution.
Learn more about acid here:
https://brainly.com/question/3700851
#SPJ2
If the temperatures were raised slowly under the same conditions, would ice made from fresh water or sea water melt first? Which would boil first? Which of these would allow the temperature of an ice cream maker to drop below 0°C? Which requires colder temperatures to freeze, unsalted roads or salted roads? Which requires more heat to boil, pure water or a sugar solution used for making candy?
Answer:
1.sea water 2.fresh water 3. Salt and ice
4.salted roads 5. Sugar solution used for making candy
Explanation:
Because Truck
Answer:
salted roads
sugar something
pure water
Explanation:
trust me bro
what happened to the sound as vibration of an object increase in strength
Answer:
A.The sound becomes louder.
And
C.The sound waves get further.
Explanation:
Louder the sound it will travel long.
Muscles and bones work together when muscles move bones through contracting and
relaxing.
A.true
B.false
I think it's true.
Explanation:
Muscles move bones through contracting and relaxing
PLEASE HELPP!
a 55g block of metal has a specific heat of 0.45 J/g°C. What will be the temperature change of this metal if 450 J of heat energy are added?
Answer:
18.18 C
Explanation:
m=55
C=0.45
Q=450zj
ch.temp=?
Q=mct
450 = (55)(.45)T
450 = 24.75
/24.75 = /24.75 (cancels out)
18.18 is the answer
how can a scientist make a solution using salt and water?
Answer:
by boiling water and add the salt
Explanation:
because salt dissolves better if mixed with hot water which makes the process faster and effective
Which one is not soluble in water Licl, lioh or li3po4
Answer:
li3po4
Explanation:
Balance the single replacement chemical reaction.
Explanation:
B) 3CuCl2+2AL..….2AlCl3+3Cu
hope it helps.
Balanced Equation:
3CuCl₂ + 2Al = 2AlCl₃ + 3Cu
811.68 J of energy are used on a 95g chunk of unknown metal. Calculate the resulting temperature change if the specific heat of the metal is 0.534 J/g*C. oC
Answer:
16 °C
Explanation:
Step 1: Given data
Provided heat (Q): 811.68 JMass of the metal (m): 95 gSpecific heat capacity of the metal (c): 0.534 J/g.°CStep 2: Calculate the temperature change (ΔT) experienced by the metal
We will use the following expression.
Q = c × m × ΔT
ΔT = Q/c × m
ΔT = 811.68 J/(0.534 J/g.°C) × 95 g = 16 °C
What is the most likely effect of people logging a forest faster than it can grow back?
The forest will eventually disappear and no longer provide any resources.
The forest will eventually reach a smaller population size and remain at that size.
The forest will gradually grow faster to keep up with increased demand.
The forest will keep its current population size and continue to provide resources.
Answer:
D
Explanation:
A growing body of scientific evidence shows that the felling of tropical forests creates optimal conditions for the spread of mosquito-borne scourges, including malaria and dengue. Primates and other animals are also spreading disease from cleared forests to people.
A watt is
A. 1 cal/s.
B. 1 joule/s.
C. 1 s/cal.
D. 1 s/joule.
Answer:
The answer would be B. 1 joule/s.
Explanation:
The answer is B because the power in general is normally defined as energy over time. Watts are defined as 1 Watt = 1 Joule per second (1W = 1 J/s) which means that 1 kW = 1000 J/s.
Another reason why it's B is because I had the same exact question in class, I took a screenshot of it a day ago:
Hope this helps
1. When there is light, photosynthesis can
A. occur, in the chloroplast.
B. not occur, and the stomata will not be open.
C. not occur, and the stomata will be open.
D. occur, in the
mitochondria.
Answer:
A
Explanation:
Answer:
A. occur, in the chloroplast.
Explanation:
Photosynthesis occur in chloroplasts, with the help of sunlight. Where mitochondria help in respiration
Question 3
Which of the objects on the shelf has the greatest inertia?
10 kg
5 kg
2kg
a
b
2 kg
5 kg
10 kg
С
d
The all have the same inertia
5.36 liters of nitrogen gas are at STP. What would be the new volume if we increased the moles from 3.5 moles to 6.0 moles?
Answer:
[tex]V_2=9.20L[/tex]
Explanation:
Hello there!
In this case, according to the given STP (standard pressure and temperature), it is possible for us to realize that the equation to use here is the Avogadro's law as a directly proportional relationship between moles and volume:
[tex]\frac{V_2}{n_2}= \frac{V_1}{n_1}[/tex]
In such a way, given the initial volume and both initial and final moles, we can easily compute the final volume as shown below:
[tex]V_2= \frac{V_1n_2}{n_1} \\\\V_2=\frac{5.36L*6.0mol}{3.5mol}\\\\V_2=9.20L[/tex]
Best regards!
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.
what type of chart is used to help organize study and predict genetic inheritance?
Answer:
Its a punnet square
Explanation:
the sum of two number is 50,and their difference is 30.find the sum
Answer:
40 and 10
Explanation:
40 plus 10 is 50 40 minus 10 is 30
Answer:
40 and 10
Explanation:
Help please I’ll mark as brainiliest
Answer:
B B
W BW BW
W BW BW
Explanation:
Hope this helps
In the context of a balanced chemical equation, a____is a number to the lower right of an element or ion within formula and it applies to____. A____is a number to the left of a formula and it applies to_____. Only_____should be added or changed when balancing chemical equations.
Answer:
Explanation:
The preceding chapter introduced the use of element symbols to represent individual atoms. When atoms gain or lose electrons to yield ions, or combine with other atoms to form molecules, their symbols are modified or combined to generate chemical formulas that appropriately represent these species. Extending this symbolism to represent both the identities and the relative quantities of substances undergoing a chemical (or physical) change involves writing and balancing a chemical equation. Consider as an example the reaction between one methane molecule (CH4) and two diatomic oxygen molecules (O2) to produce one carbon dioxide molecule (CO2) and two water molecules (H2O). The chemical equation representing this process is provided in the upper half of Figure 1, with space-filling molecular models shown in the lower half of the figure.
What is a renewable resource on Earth?
minerals
coal
wind
petroleum
Answer:
Wind
Explanation:
Wind turbines make energy by the movement of the natural force on earth called 'wind' and renewable resources are resources that can be made from natural and environment-safe objects or things (e.g. Water, Geothermal Heat, The Sun, and Wind)
A chemist weighed out 7.22 g of silver. Calculate the number of moles of silver she weighed out.
Be sure your answer has the correct number of significant digits.
Answer:
0.067 mole Ag°
Explanation:
Given 7.22 g Ag° = 7.22g Ag/ 107.8g/mol = 0.0670 mole Ag° (3 sig. figs.)
PlEASE HELP! 40!
A radioactive form of sodium pertechnetate is used as a brain-scanning agent in medicine. Quantitative analysis of a sample with a mass of 0.8961 g found 0.1114 g of sodium and 0.4749 g of technetium. The remainder was oxygen. Determine the empirical formula.
Answer:
moles Na = 0.1114 g / 22.9898 g/mol=0.004846
moles Tc = 0.4562g /98.9063 g/mol=0.004612
mass O = 0.8961 - ( 0.1114 + 0.4562)=03285 g
moles O = 0.3285 g/ 15.999 g/mol=0.02053
divide by the smallest
0.02053/ 0.004612 =4.45 => O
0.004846/ 0.004612 = 1.0 => Tc
to get whole numbers multiply by 2
Na2Tc2O 9
Explanation:
Hope it right hope it helps
How do humans influence genetic outcomes in artificial selection and what impacts does this have on society?
Answer:
In artificial selection, humans have the capacity to influence certain characteristics of organisms by selective breeding. One can choose desired parental traits determined by genes, which are then passed on to offspring.
a freshwater stream flows into the ocean as shown in the diagram which statement correctly describes how the stream affects these salinity of the ocean
A- salinity increases because the stream adds salt to the ocean.
B- salinity decreases because the stream adds freshwater to the ocean
C- salinity increases because of stream adds freshwater to the ocean
D- salinity Remains the Same because the stream adds freshwater to the ocean
Is vinegar and rubbing alcohol soluble or insoluble?
Five identical test tubes are each filled from the following five copper (11) sulfate stock solutions. Which of the following test tubes would appear the lightest blue?
a) Stock solution made form 0.200 moles of CuSO4 dissolved to a total volume of 400 ml
b) Stock solution made form 0.150 moles of CuSO4 dissolved to a total volume of 300 mL
C)Stock solution made form 0.250 moles of CuSO4 dissolved to a total volume of 500 ml
d) Stock solution made form 0.175 moles of CuSO4 dissolved to a total volume of 400 ml
e) Stock solution made form 0.125 moles of CuSO4 dissolved to a total volume of 300 ml
Answer:
deez cutz
Explanation:
did i get it right