Answer:
0.81 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 we have
[tex]n = \frac{4.9 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{4.9}{6.02} \\ = 0.813953...[/tex]
We have the final answer as
0.81 molesHope this helps you
What is the lengthening of a muscle without damage? And what is the shortening of a muscle?
Answer:
Stretching is the lengthening and contraction is the shortening
Explanation:
Unless it's asking for eccentric as the stretching and concentric as the shortening
Dominant traits are more common in a population then recessive traits
false
true
Answer:
No Just because a trait is dominant does not mean that it is present in the population
Explanation:
Suppose that scientists want to study a feature of the galaxy that is very far away. They decide to use a telescope that observes high-energy gamma rays. Explain why this would be a good choice.
Answer & Explanation:
Gamma rays are the most energetic form of electromagnetic radiation. By observing the distant galaxy at gamma-rays, scientists can search for new physics, test theories, and perform experiments that are not possible in earth-bound laboratories.
A moving 10 kilogram object has 20 Joules of kinetic energy. What is its velocity?
4 m/s
2 m/s
10 m/s
200 m/s
ANSWER THIS GET 25 POINTS!!!!
Sam is walking in a garden on a day represented by the figure above. Which plants in the garden could be blooming on this day?
A:long-day and day-neutral plants
B: day-neutral plants only
C: short-day and day-neutral plants
D: short-day, long-day, and day-neutral plants
Answer:
C: short-day and day-neutral plants
Explanation:
There is no figure above.
different between intermolecular and intra molecular dehydration
Answer: Intermolecular bonds are the forces between the molecules. Intramolecular are the forces within two atoms in a molecule.
Explanation:
DUE IN 1 MINUTE HELP I'M DESPERATE
No changes will ever be made to the scientific classification system. Is this a valid statement? Why or why not? HELP PLZ GIVING BRANLIESTTT
Answer:
No.
Explanation:
Since classification, is a system of categorizing living things new discoveries; animals are discovered everyday. There are some we didn't discover yet, so the scientists are going to have to make another one for the future.
No changes will ever be made to the scientific classification system. This is not a valid statement.
What is scientific classification?Biological Classification is the way scientists use to categorize and organize all of life. It can help to distinguish how similar or different living organisms are to each other
Millions of plants, animals, and microorganisms found on earth, have been identified by the scientists while many new species are still being discovered around the world.
Thus, to classify these newly discovered species, with new characters, new systems of classification have to be devised every now and then.
Therefore, No changes will ever be made to the scientific classification system. This is not a valid statement.
Learn more about scientific classification, here:
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Can light bend around corners to reach an object
Answer: Yes, light can bend around corners. In fact, light always bends around corners to some extent.
Explanation:This is a basic property of light and all other waves. ... The ability of light to bend around corners is also known as "diffraction".
what role does the grass play in the food web?
A. Producer B. Primary Consumer C. secondary Consumer D. Decomposer
Answer:
Producer
Explanation:
I took the test :)
The local weather station is predicting that a warm front will pass through Charlotte, NC in two days.
How will Charlotte's weather most likely be affected by the passing of a warm front?
A The wind speed will decrease.
B The air pressure will increase.
C the temperature will increase.
D The temperature will decrease.
Answer:
C the temperature will increase.
34 g of O2 are reacted with excess Cs, causing a production of 199 g of Cs2O. What is the percent yield of this
reaction?
2 Cs + O2 ---> Cs2O
Answer:
33.23 %
Explanation:
4 Cs + O₂ → 2Cs₂OFirst we convert 34 g of O₂ into moles, using its molar mass:
34 g O₂ ÷ 32 g/mol = 1.0625 mol O₂Then we convert O₂ moles into Cs₂O moles, using the stoichiometric coefficients of the balanced reaction:
1.0625 mol O₂ * [tex]\frac{2molCs_2O}{1molO_2}[/tex] = 2.125 mol Cs₂ONow we convert 2.125 moles of Cs₂O into grams, using its molar mass:
2.125 mol Cs₂O * 281.81 g/mol = 598.85 g Cs₂O598.85 g is the theoretical yield. Finally we proceed to calculate the percent yield:
199 / 598.85 * 100% = 33.23 %HELPP PLZ FAST WILL GIVE BRAINLIEST
Benzene, a nonpolar, colorless solute, is most commonly found in oil and is a major component in gasoline.
In which of these two solvents will benzene most likely dissolve?
Solvent
Characteristics
A
Carbon tetrachloride
• Colorless liquid, noncombustible
• Nonpolar
Ethanol
• Flammable, colorless liquid
• Polar
Methanol
• Distinctive odor; volatile, colorless liquid
• Polar
Cyclohexane
• Strong odor; flammable; colorless liquid
• Nonpolar
OA
OB
ОС
OD
what is the major organic product obtained from the reaction of 1-butanol with aqueous hbr at reflux
Answer:
1-bromobutane
Explanation:
The reaction of butane with aqueous HBr at reflux is an SN2 reaction. The reaction passes through a single transition state in which the bond between carbon and the leaving group as well as the bond between carbon and the incoming nucleophile are being broken and formed simultaneously. It is a synchronous reaction.
The nuclephile attacks from the backside while the leaving group departs. This leads to inversion of configuration of the product.
how do you think a device could change the sound that we hear? Make sure you use vocabulary such as frequency, energy and amplitude
Answer:
good luck tho
Explanation:
Characterize the effect that changes will have on the vapor pressure (v.p.) and boiling point (b.p.) of a liquid by increasing the external pressure on the surface of a liquid at constant temperature. Group of answer choices v.p. does not change, b.p. decreases v.p. decreases, b.p. decreases v.p. does not change, b.p. increases v.p. decreases, b.p. does not change
Answer:
Vapor pressure does not changes , Boiling point of liquid increases.
Explanation:
The external pressure creates the water molecules to move rapidly. The boiling point of liquid will increase as a result of external pressure induced on the surface of the liquid. The temperature must be kept constant to bring the liquid to boil.
How do you balance this:
Br2 + H2O + SO2 = HBr + H2SO4
Answer:
Br2+ 2H2O + SO2= 2HBr + H2SO4
Let's Compare the left side of the equation to the right side of the equation.
Left: Br= 2, H= 2, S= 1, O = 1+2
Right: Br=1, H= 1+2, S=1, O= 4
We can see that only S is balanced and not the other 3 elements.
I'll try to make each element balance.
For Br; I'll multiply by 2 on the left to make it equal to the right.
For H; Since the 2 for Br on the right affected also H, that H ( for HBr) Already has a 2, but then it adds with the other H2( for H2SO4) to give a total of 4 H on the right side. But then there's only 2 H on the left. so we multiply that 2 by a 2 ( which is written infront of the H2O to give a total of 4 H on the left side.
For O; Because of the 2 infront of the H2O, it affects the O in H2O..so now we have 2 O plus the 2 O ( in SO2) to give a total of 4 O which is equal to the right side.
What do concentric contour lines on a topographic map represent?
Answer:
Concentric circles of contour lines indicate a hilltop; concentric circles with hachure marks indicate a close depression.
Explanation:
Hope this helped Mark BRAINLIEST!!!
Reaction of HBr with 3-methylcyclohexene yields a mixture of four products cis-and trans-1-bromo-3-methylcyclohexane and cis-and trans-1-bromo-2-methylcyclohexane. The analogous reaction of HBr with 3-bromocyclohexene yields trans-1,2-dibromocyclohexane as the soul product.
Required:
Draw structures of the possible intermediates and mechanismfor the latter reaction.
Answer:
See explanation
Explanation:
The mechanism of this reaction including intermediates are shown in the image attached to this answer.
The reaction of HBr with 3-bromocyclohexene yields trans-1,2-dibromocyclohexane as the sole product because; the proton first attacks the 3-bromocyclohexene and a brominium ion is formed. This brominium ion is a cyclic intermediate as shown in the image attached.
Attack of a bromine ion afterwards must lead to the formation of trans-1,2-dibromocyclohexane as shown.
What products will form when potassium is added to cold, liquid water?
A.) no reaction will occur
B.) potassium oxohydride and hydrogen
C.) potassium hydroxide and hydrogen
4.) potassium oxide and hydrogen
Answer:
C
Explanation:
Potassium metal reacts very rapidly with water, which forms Potassium hydroxide (KOH) and hydrogen gas (H2).
Answer:
The answer is C
Explanation:
i took a test on this.
A sample of chlorine gas has a volume of 0.30 L at 273 K and 1 atm pressure. What temperature (in ∘C) would be required to increase the volume to 1.0 L ?
Answer:
[tex]T_2=637\°C[/tex]
Explanation:
Hello there!
In this case, considering this problem as pressure constant, since the change is exhibited in temperature and volume only, it is possible for us to use the Charles' law as shown below:
[tex]\frac{V_2}{T_2}=\frac{V_1}{T_1}[/tex]
Thus, by solving for the final temperature, we obtain:
[tex]T_2=\frac{T_1V_2}{V_1}\\\\T_2=\frac{273K*1L}{0.30L}\\\\T_2=910K-273\\\\T_2=637\°C[/tex]
Best regards!
What is the value for AG at 5000 K if AH = -220 kJ/mol and S= -0.05 kJ/(mol-K)?
A. -195 kJ
B. -470. kJ
C. 30 kJ
D. 470 kJ
Answer:
C. 30 kJ
Explanation:
Hello there!
In this case, in agreement to the thermodynamic definition of the Gibbs free energy, in terms of enthalpy of entropy:
[tex]\Delta G= \Delta H-T\Delta S[/tex]
It is possible to calculate the required G by plugging in the given entropy and enthalpy as shown below:
[tex]\Delta G=-220kJ/mol-5000K*-0.05kJ/mol*K\\\\\Delta G=30kJ/mol[/tex]
Therefore, the answer is C. 30 kJ .
Best regards!
It takes 45.60 mL of a 0.225 M hydrochloric acid solution to react completely with 25.00 mL of calcium hydroxide in this reaction below, what is the molar concentration of the calcium hydroxide solution?
2HCl(aq) + Ca(OH)2(aq)!CaCl2(aq) + 2H2O(l)
Given :
It takes 45.60 mL of a 0.225 M hydrochloric acid solution to react completely with 25.00 mL of calcium hydroxide in the given reaction.
2HCl(aq) + Ca(OH)2(aq) --> CaCl2(aq) + 2H2O(l)
To Find :
The molar concentration of the calcium hydroxide solution.
Solution :
From given equation 2 mole of hydrochloric acid react with 1 mole of calcium hydroxide.
So,
[tex]2M_1V_1 = M_2V_2\\\\2\times 0.225 \times 45.60 = M_2 \times 25 \\\\M_2 = \dfrac{20.52}{25}\\\\M_2 = 0.8208 \ M[/tex]
Therefore, molar concentration of the calcium hydroxide solution is 0.8208 M.
Answer:
Molar concentration of the calcium hydroxide solution = 0.2052 M
Explanation:
Volume of HCl = 45.60 mL = 0.0456 L
Molar concentration of HCl = 0.225 M
Volume of Ca(OH)2 = 25.00 mL = 0.025 L
No. of moles of HCl = (0.225 M)*(0.0456 L) = 0.01026 mol
As we know
2 moles of HCl require 1 mole of Ca(OH)2, hence, .01026 moles of HCl will need 0.5*(0.01026) = 0.00513 moles of Ca(OH)2
Molar concentration of Ca(OH)2 = [(0.00513 mol)/(0.025 L)] = 0.2052 M
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 happened on March 15 in the year 44 B.C.? Caesar began a civil war. Caesar's enemies killed him. C. The Council of the Plebs met. d. All enslaved people were freed. Please select the best answer from the choices provided Com o C
Answer:
Caesar's enemies killed him.
Explanation:
On March 15, 44 B.C.E., Julius Caesar was stabbed to death in Rome, Italy. . A group of as many as 60 conspirators decided to assassinate Caesar at the meeting of the Senate on March 15, the ides of March.
Hope this helped!!!
determine the kinetic energy of a 1000-kg rollor coaster car that is moving with the speed of 20.0 m/s
Given :
Mass of roller coaster, m = 1000 kg.
Speed with which roller coaster is moving, v = 20.0 m/s.
To Find :
The kinetic energy if roller coaster.
Solution :
We know, kinetic energy of any object of mass m and speed v is given by :
[tex]K.E = \dfrac{mv^2}{2}\\\\K.E = \dfrac{1000\times 20^2}{2}\ J\\\\K.E = 200000\ J\\\\K.E = 200\ kJ[/tex]
Therefore, the kinetic energy of roller coaster is 200 kJ.
fossil fuels form in sedimentary rocks when-
Answer:
fossil fuels form in sedimentary rocks when increased heat and pressure applies to fossils.
Explanation:
fossil fuels are made when sedimentary rock gets heat and pressure increased.
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!
If objects with a greater mass have greater gravitational pull, why is our solar
system, Sun, planets and asteroids, NOT pulled into Alpha Centauri A?
Answer:
It's too far away
Explanation:
According to classical mechanics, gravitational pull is inversely proportional to the distance squared; as the distance increases, the gravitational pull decreases at a faster and faster rate. Since Alpha Centauri A is a few lightyears (Tens of trillions of kilometers away), without even needing to calculate the force of gravity, it is very miniscule.
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