Answer: 1 mole = 6.02 x 10^ 23
Explanation:
The number of atoms in one mole of helium is equal to 6.022×10²³ He atoms.
What is Avogadro's number?Avogadro’s constant can be demonstrated as the proportionality factor that utilizes to count the number of particles such as ions, molecules, atoms, or ions in a sample of the substance.
Avogadro's number can be defined as the approximate count of nucleons in 1 gram of substance. The value of the Avogadro number is the mass of 1 mole of a compound, in grams, and is the number of nucleons in one particle.
The value of Avogadro’s number is equal to 6.022×10²³ per mole.
Given, the number of moles of the helium = 1 mol
Helium is a monatomic gas so it contains only one atom in its one molecule.
The number of atoms of Helium in one mole = 6.022 × 10²³
Therefore, the total number of atoms contained in a 1 mole sample of
helium is 6.022 × 10²³.
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If the solubility of salicylic acid is 77.8 g/L of water at 100oC and 1.4 g/L of water at 10oC, a) calculate the minimum amount (in mL) of boiling water necessary to dissolve 2.0 g of impure salicylic acid for recrystallization. b) If the solution is cooled to room temperature and then to 10oC with an ice/water bath, what is the maximum amount of solid salicylic acid isolated after vacuum filtration
Answer:
a. 25.7mL are necessaries.
b. 1.964g of salicylic acid can be isolated.
Explanation:
a. As the solubility of salicylicic acid in boiling water is 77.8g/L, to dissolve 2.0g of salicylic acid are necessaries:
2.0g * (1L / 77.8g) = 0.0257L =
25.7mL are necessariesb. Then, at 10°C the solution just can dissolve 1.4g/L, that is:
0.0257L * (1.4g/L) = 0.036g of salicylic acid are dissolved.
And will precipitate:
2.0g - 0.036g =
1.964g of salicylic acid can be isolatedURGENT A gas occupies a volume of 2.4 L at 0.14 ATM. What volume will the gas occupy at 0.84 ATM ?
a
0.28 L
b
14 L
c
0.40 L
d
2.5 L
Answer:
c 0.40 L
Explanation:
Calculate by using Boyle's Law P₁V₁=P₂V₂
(0.14atm)(2.4L) = (0.84atm)(V₂)
0.336 atmL = (0.84atm)(V₂)
V₂ = 0.336 atmL/0.84atm
V₂ = 0.4 L
Compared to water, metals heat up faster because they have
Answer: the answer would be a lower specific heat.
Explanation:
I am doing a exam in science need help.
What type of energy comes from the motion of tiny particles of matter?
Answer:
here you are
Explanation:
atomic energy
Calculate the moles of argon gas at STP in 33 L. Round answer to 2 significant figures.
Answer:
1.5 mol
Explanation:
Step 1: Given data
Volume of argon gas: 33 LStandard temperature: 273.15 KStandard pressure: 1 atmStep 2: Calculate the moles corresponding to 33 L of argon at standard temperature and pressure (STP)
At STP, 1 mole of argon gas occupies 22.4 L.
33 L × 1 mol/22.4 L = 1.5 mol
Calculate the pH of a 0.75 M solution of H2SO4.
Answer:
न्द्न्द्ज्द्ज्फ्ज्फ्ज
Use this picture to explain that an electrically charged object can attract an uncharged object without any contact. Your answer should be at least three sentences long. (2 points) a balloon hanging from a string with small pieces of paper stuck to the bottom of it, with a few pieces on the ground
Answer: Insufficient amount of work provided.
Explanation:
3. Pepsi puts 355 ml of soda in a can. How many drops is this?
Wich stament describes to organ systems working together to get rid of waste played by cells
Answer:
C. Kidneys filter wastes from the bloodstream and produce urine
Explanation:
8. 53.4 mL of a 1.50 M solution of NaCl is on hand, but you need some 0.800 M
solution. How many mL of 0.800 M can you make?
9. A stock solution of 1.00 M NaCl is available. How many milliliters are needed
to make 100.0 mL of 0.750 M
10.2.00 L of 0.800 M NaNO, must be prepared from a solution known to be 1.50
M in concentration. How many mL are required?
PLS answer ASAP!! WILL MARK AS BRAINLYIST!
Write a mechanism for the conversion of the aldol addition product, 3-hydroxy-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propanone, to the aldol condensation product, (E)-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propenone. Be as complete as possible and show electron flow for all steps.
Solution :
"Aldol" stands for the abbreviation, aldehyde and alcohol. When a ketone or an aldehyde's enolate reacts with the carbonyl of a molecule at the alpha carbon, under the acidic or basic conditions so as to obtained the ketone or β-hydroxy aldehyde, is known as an aldol reaction.
For the conversion of the aldol addition product of a 3-hydroxy-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propanone to an aldol condensation product of (E)-3-(4-nitrophenyl)-1-(2-pyridyl)-1-propenone, the mechanism is given in the diagram a below :
Element R has three isotopes. The isotopes are present in 0.0825, 0.2671, and 0.6504 relative
abundance. If their masses are 81, 115, and 139 respectively, calculate the atomic mass of element
R. (No decimals).
The average atomic mass of the element R that has three isotopes is 127.805.
How to calculate average atomic mass?Average atomic mass is the weighted average of the atomic masses of the naturally occurring isotopes of an element.
The average atomic mass of an element can be calculated by summing up the product of the percent abundance and masses of each isotope as follows;
Average atomic mass of R = (0.0825 × 81) + (0.2671 × 115) + (0.6504 × 139)
Average atomic mass = 6.6825 + 30.7165 + 90.4056 = 127.805
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What products will form when bromine is added to gallium chloride?*
A.)no reaction will occur
B.)gallium bromide and chlorine
C.)gallium bromine and chloride
D.)bromine chloride and gallium
Calculate the percent by mass of the solute in an aqueous solution of 27.2 g ethanol in 250 g of total solution.
Answer:
Explanation:
H
Mass percent can be calculated from the mass of solute in grams divided by the mass of solution multiplied by 100. The percent by mass of the solute in aqueous solution of 27.2 g ethanol in 250 g of total solution 10.88 %.
What is mass percentage?Mass percentage is term used to represent the concentration of a solution. Mathematically mass percent of a component in a mixture is the mass of the component divided by the total mass multiplied by 100.
A solution is made of a solvent and solute. Thus, the total mass of the solution is the sum of mass of solute and mass of the solvent. Here, the solute is ethanol with a mass of 27.2 g. The total mass of solution is 250g.Hence, the mass percent of ethanol can be calculated as follows:
Mass percent of ethanol = mass of ethanol/total mass ×100
= (27.2/250)×100
= 10.88 %.
Hence, the percent by mass of solute ethanol in the total solution is 10.88%.
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Climate indicators are events occurring that identify climate change as more than a change in temperature. What is happening to each event as
the climate changes?
Temperatures are
sea levels are
carbon dioxide levels in the atmosphere are
, and the amount of sea ice is
For the blanks it’s either increasing or decreasing
Answer:
As the climate changes, temperatures are increasing, sea levels are rising, carbon dioxide levels in the atmosphere are increasing, the pH of the ocean is decreasing, and the amount of sea ice is decreasing.
Explanation:
A gas has a volume of 10 L at 200 K and a pressure of 1.5 atm . What would the volume of the gas be at 300 K and 2atm of pressure ?
Answer:
jeyjeyjetnetney
Explanation:
thmrhmrhmrum
Would a salt-cured egg be a physical or chemical change?
For a science experiment, I placed an egg in water that had three tablespoons of salt for one week. After 4 days, the egg cracked. At the end of the week, I took it out and cracked the egg. The egg yolk was now solid. This is also called salt-cured eggs. However, I'm not sure whether this is a physical or chemical change.
Answer:
I believe it is a physical change
Explanation:
The telltale sign of a chemical change is the formation of a new substance. They also usually involve the production of energy (heat, light, sound etc.)
What is the mass in grams of 8.65 mol C8H18?
Answer in standard notation to zero decimal places.
PLEASE HELP THIS IS DUE AT 11:59 AT MIDNIGHT AND IM FREAKING OUT
Answer:
m = 998 g
Explanation:
Hello there!
In this case, according to the definition of the molar mass as the mass of one mole of the compound, it is possible to state the 1 mole of C8H18 has a mass of 114.26 grams; therefore, the mass in 8.65 moles turn out to be:
[tex]m=8.65mol*\frac{114.26g}{1mol}\\\\m=998g[/tex]
In agreement to the notation requirement.
Best regards!
Aqueous solutions containing approximately 3 percent(w/w) H2O2 are sold in drug stores as a disinfectant. Determination of the actual concentration of H2O2 in a bottle of peroxide solution was done by diluting 1.50 mL to 100 mL with water, acidifying with dilute H2SO4 and titrating with a 0.01411 M KMnO4 solution. 32.17 mL of the permangate solution was needed to reach the end point of the titration. What is the actual molar concentration of the H2O2 solution]
Answer:
0.01804 M KMnO4 Solution.
Explanation:
3 Percent(w/w) H2O2 Are Sold In Drug Stores As A Disinfectant. ... H2O2 In A Bottle Of Peroxide Solution Was Done By Diluting 1.50 ML To 100 ML With Water, Acidifying With Dilute H2SO4 And Titrating With A 0.01804 M KMnO4 Solution.
Using the rules that we developed in this chapter (ARIO), we might have expected these two compounds to have the same pKa. Nevertheless, they are different. Salicylic acid is apparently more acidic than its constitutional isomer. Can you offer an explanation for this observation
Answer:
The correct answer is
- after deprotonation carboxylic acid stabilizes by binding -OH group with hydrogen bonding in salicylic acid and while it's not possible with its constitutional isomer (para-hydroxy benzoic acid).
The more electronegative atoms are replaced by the H atom of the carboxylic group and form more stabilize carboxylic acid which not takes place in para-hydroxy benzoic acid.
Why does a red object appear red?
O A. It reflects light of wavelengths other than red.
OB. It absorbs light of red wavelengths.
O C. It absorbs light of wavelengths other than red.
O D. It reflects infrared radiation.
Right answers only for brainly
Answer:
Objects appear different colours because they absorb some colours (wavelengths) and reflected or transmit other colours. ... For example, a red shirt looks red because the dye molecules in the fabric have absorbed the wavelengths of light from the violet/blue end of the spectrum
A red object appear red because it absorbs light of wavelengths other than red. Therefore, option C is correct.
What is wavelength ?The distance between identical points (adjacent crests) in adjacent cycles of a waveform signal propagated in space or along a wire is defined as the wavelength. This length is typically specified in wireless systems in meters (m), centimeters (cm), or millimeters (mm) (mm).
A transverse wave's wavelength is defined as the distance between two adjacent crests. A longitudinal wave's wavelength can be calculated as the distance between two adjacent compressions.
The wavelengths that are reflected or transmitted are what we see as colors. A red shirt, for example, appears red because the dye molecules in the fabric have absorbed light wavelengths from the violet/blue end of the spectrum. The only light reflected from the shirt is red light.
Thus, option C is correct.
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Only 5 minutes to answer!
Why are the weather satellites important on Mars?
Answer:
they can track the weather which can show if it would be posssible to live or have life on mars
Explanation:
The Earth's asthenosphere is a structural layer
A.
that is made of the crust and the uppermost part of the mantle.
B.
that is contained completely within the crust.
C.
that is contained completely within the upper mantle.
D.
that is made of the mantle and the uppermost part of the crust.
Answer:
Dont completly trust me here but i think its a but id try and wait for someone else just be careful
Explanation:
What is the molarity of the resulting solution when 300. mL of a 0.400 M solution is diluted to 800.
mL?
Answer:
0.150M
Explanation:
hope it helps!!!!!!!!!!!!
The molarity of the resulting solution when 300. mL of a 0.400 M solution is diluted to 800 mL is 0.15M.
Molarity is defined as the ratio of the number of moles of solute present in a solution, to the volume of that particular solution in litres.
It is calculated by using the formula
M₁V₁ = M₂V₂
M₁= initial molarity of the solution
V₁ = initial volume of the solution
M₂ = final molarity of the solution
V₂ = final volume of the solution
Given data,
M₁ = 0.400 M (initial molarity)
V₁ = 300 mL (initial volume)
V₂ = 800 mL (final volume)
Substituting the values we get
M₁V₁ = M₂V₂
.4× 300/800 = M₂
Therefore, molarity of the resulting solution = .15
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Why do you think there are different stars in each nighttime section of the artifact?
Answer:
The sky looks different in each nighttime section of the artifact because the artifact sections represent different seasons. ... Different constellations are visible on different nights throughout the year because of the earth's orbit. The Earth orbits around the sun. A full orbit is 365 days or one year.
Explanation:
What do you think a mutation is?
What is the entropy of this collection of training examples with respect to the positive class B. What are the information gains of A1 and A2 relative to the training dataset For A3, which is a continuous attribute, compute the information gain for every possible split. C. What is the best split (among A1,A2, and A3) according to the information gain
The data set is missing in the question. The data set is given in the attachment.
Solution :
a). In the table, there are four positive examples and give number of negative examples.
Therefore,
[tex]$P(+) = \frac{4}{9}$[/tex] and
[tex]$P(-) = \frac{5}{9}$[/tex]
The entropy of the training examples is given by :
[tex]$ -\frac{4}{9}\log_2\left(\frac{4}{9}\right)-\frac{5}{9}\log_2\left(\frac{5}{9}\right)$[/tex]
= 0.9911
b). For the attribute all the associating increments and the probability are :
[tex]$a_1$[/tex] + -
T 3 1
F 1 4
Th entropy for [tex]$a_1$[/tex] is given by :
[tex]$\frac{4}{9}[ -\frac{3}{4}\log\left(\frac{3}{4}\right)-\frac{1}{4}\log\left(\frac{1}{4}\right)]+\frac{5}{9}[ -\frac{1}{5}\log\left(\frac{1}{5}\right)-\frac{4}{5}\log\left(\frac{4}{5}\right)]$[/tex]
= 0.7616
Therefore, the information gain for [tex]$a_1$[/tex] is
0.9911 - 0.7616 = 0.2294
Similarly for the attribute [tex]$a_2$[/tex] the associating counts and the probabilities are :
[tex]$a_2$[/tex] + -
T 2 3
F 2 2
Th entropy for [tex]$a_2$[/tex] is given by :
[tex]$\frac{5}{9}[ -\frac{2}{5}\log\left(\frac{2}{5}\right)-\frac{3}{5}\log\left(\frac{3}{5}\right)]+\frac{4}{9}[ -\frac{2}{4}\log\left(\frac{2}{4}\right)-\frac{2}{4}\log\left(\frac{2}{4}\right)]$[/tex]
= 0.9839
Therefore, the information gain for [tex]$a_2$[/tex] is
0.9911 - 0.9839 = 0.0072
[tex]$a_3$[/tex] Class label split point entropy Info gain
1.0 + 2.0 0.8484 0.1427
3.0 - 3.5 0.9885 0.0026
4.0 + 4.5 0.9183 0.0728
5.0 -
5.0 - 5.5 0.9839 0.0072
6.0 + 6.5 0.9728 0.0183
7.0 +
7.0 - 7.5 0.8889 0.1022
The best split for [tex]$a_3$[/tex] observed at split point which is equal to 2.
c). From the table mention in part (b) of the information gain, we can say that [tex]$a_1$[/tex] produces the best split.
How many protons are in nitrogen
Answer:
Explanation:
There are 7 protons in nitrogen
7 TYPE OF NITRONGEN
. . .
The weak base ionization
constant (Kb) for C4H4N2 is
equal to
Answer:
A
Explanation:
The weak base ionization constant (Kb) for [tex]C_{4} H_{4} N_{2}[/tex] is equal to Option A.
Are weak foundations made of ionized?A weak foundation is a base that makes ionize only slightly in an aqueous solution. Remember that a foundation can be defined as an object, which receives a hydrogen ion from another object.
What is the kb of a weak foundation?To obtain an aqueous solution of a weak acid, the dissociation constant is called the acid ionization constant (Ka). Similarly, the constant equilibrium of a weak base reaction with water is the base ionization constant (Kb). In any conjugate acid-base pair, KaKb = Kw.
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someone please answer this question i will mark you brainliest!!