Answer:
25 minutes
Explanation:
V = Volume = [tex]90\ \text{m}^3[/tex]
[tex]C_0[/tex] = Radon concentration under steady state = 1.5 Bq/L
k = Radon decay rate = [tex]2.09\times 10^{-6}\ \text{s}^{-1}[/tex]
[tex]Q[/tex] = Venting rate = [tex]0.14\ \text{m}^3/\text{s}[/tex]
[tex]C_f[/tex] = Final concentration of radon = 0.15 Bq/L
Theoretical detention time is given by
[tex]\theta=\dfrac{V}{Q}\\\Rightarrow \theta=\dfrac{90}{0.14}\\\Rightarrow \theta=642.86\ \text{s}[/tex]
We have the relation
[tex]C_f=C_0e^{-(\dfrac{1}{\theta}+k)t}\\\Rightarrow t=\dfrac{\ln\dfrac{C_f}{C_0}}{-(\dfrac{1}{\theta}+k)}\\\Rightarrow t=\dfrac{\ln\dfrac{0.15}{1.5}}{-(\dfrac{1}{642.86}+2.09\times 10^{-6})}\\\Rightarrow t=1478.25\ \text{s}=\dfrac{1478.25}{60}=24.63\approx 25\text{minutes}[/tex]
The time taken to reach the acceptable level of concentration is 25 minutes.
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.
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.
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
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.
As mentioned in the kinetic molecular theory, what is the main reason that the volume of gas particles can be considered zero?
a)The bonds present in gas particles are stronger than other bonds, pulling atoms in closer to each other, causing a shorter bond length which greatly decreases the volume.
b)When atoms enter the gas phase, they are less affected by gravity, which lowers their mass and in turn, their volume.
c)The real volume of the gas particles is extremely small when compared to the entire volume of their container.
d)Gas particles constantly expand and contract, which constantly alters their volume. When these volumes are averaged, a value of zero is obtained.
Answer:
The real volume of the gas particles is extremely small when compared to the entire volume of their container.
d)Gas particles constantly expand and contract, which constantly alters their volume. When these volumes are averaged, a value of zero is obtained
Explanation:
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!
A student investigated whether the number of bees he saw was related to the temperature outside. His results are on the graph below. Explain the relationship between temperature and the number of bees he saw. Use evidence from the graph to support your answer
Answer:
OOH a lot of points! too bad you scammed me :) its what you get i gueess
Explanation:
Answer:
The number of bees increased as the heat increased.
Explanation:
The line is on a steady 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 %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!
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
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
A 0.6467-g portion of manganese dioxide was added to an acidic solution in which 1.1701 g of a chloride-containing sample was dissolved. Evolution of chlorine took place as a consequence of the following reaction: After the reaction was complete, the excess was collected by filtration, washed, and weighed, and 0.3104 g was recovered. Express the results of this analysis in terms of percent aluminum chloride.
Answer:
29.39% of AlCl₃ in the sample
Explanation:
Based on the reaction:
MnO₂(s) + 2Cl⁻ + 4H⁺ → Mn²⁺ + Cl₂(g) + 2H₂O
We can find the amount of chloride in solution with the amount of MnO₂ that reacted as follows:
Initial mass MnO₂ = 0.6467g
Recovered mass = 0.3104g
Mass that reacted = 0.6467g - 0.3104g = 0.3363g
Moles MnO₂ -Molar mass: 86.9368g/mol-:
0.3363g * (1mol / 86.9368g) = 3.868x10⁻³ moles MnO₂
Moles Cl⁻:
3.868x10⁻³ moles MnO₂ * (2mol Cl⁻ / 1mol MnO₂) = 7.737x10⁻³ moles Cl⁻
Moles of AlCl₃ and mass -Molar mass AlCl₃: 133.34g/mol-:
7.737x10⁻³ moles Cl⁻ * (1mol AlCl₃ / 3mol Cl⁻) = 2.579x10⁻³ moles AlCl₃
2.579x10⁻³ moles AlCl₃ * (133.34g / mol) =
0.3439g of AlCl₃ are present in the sample.
The percent is:
0.3439g of AlCl₃ / 1.1701g * 100 =
29.39% of AlCl₃ in the sampleDUE 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:
https://brainly.com/question/30831361
#SPJ3
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.
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.
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".
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.
Gallium (, ) is a metalloid obtained from its salts during the smelting of ores of other elements, like Zinc. has broad applicability in the electronics industry. It is also used as a safe replacement for mercury in thermometers as it melts at and has a heat of fusion of . What is the entropy change of of gallium in as it melts when placed on a surface at
The given question is incomplete. The complete question is:
Gallium (Ga, 69.723 g/mol) is a metalloid obtained from its salts during the smelting of ores of other elements, like Zinc. has broad applicability in the electronics industry. It is also used as a safe replacement for mercury in thermometers as it melts at 29.8 °C and has a heat of fusion of 5.59 kJ/mol. What is the entropy change of 22 g of gallium in J/K as it melts when placed on a surface at 29.8°C?
Answer: The entropy change of of gallium in as it melts when placed on a surface at is 5.81 J/K
Explanation:
Latent heat of fusion is the amount of heat required to convert 1 mole of solid to liquid at atmospheric pressure.
Amount of heat required to melt 1 mole of Ga = 5.59 kJ
Mass of Ga given = 22 gram
Heat required to melt 69.723 g of Ga = 5.59 kJ
Thus Heat required to melt 22 g of Ga = [tex]\frac{5.59kJ}{69.723}\times 22=1.76kJ[/tex]
Temperature = [tex]29.8^0C=(273+29.8)kJ=302.8kJ[/tex]
Now entropy change = [tex]\frac{\text {heat of fusion}}{\text {temperature in K}}=\frac{1.76kJ}{302.8K}=0.00581kJ/mol=5.81J/K[/tex]
Thus the entropy change of of gallium in as it melts when placed on a surface at [tex]29.8^0C[/tex] is 5.81 J/K
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.
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 :)
What is the change in enthalpy when 180 g of water vapor condenses at 100°C? (AH, = 40.67 kJ/mol)
a. 565 kJ
b. -565 kJ c.
-407 kJ d.
407 kJ
Answer:
[tex]Q=-407kJ[/tex]
Explanation:
Hello there!
In this case, considering that the heat has two forms, sensible (variable temperature) and latent (constant temperature), we can notice that phase changes account for latent heat as the temperature remains the same. In such a way, given the enthalpy of vaporization of water, 40.67 kJ/mol, the enthalpy of condensation (reverse process) is the negative value, -40.67 kJ/mol; therefore, the associated latent heat would be:
[tex]Q=180g*\frac{1mol}{18.02g} *-40.67\frac{kJ}{mol} \\\\Q=-407kJ[/tex]
Best regards!
The answer is
C) -407 kJ d
A double-replacement reaction takes place when aqueous Na,co, reacts with aqueous Sn(NO3), according to the following equation. Na,co, + Sn(NO,)
You would expect one of the products of this reaction to be
20
Sn2(CO3)2
NaNO,
O Nas
OCNO,
Answer:
[tex]Sn(CO_3)_2[/tex] and [tex]NaNO_3[/tex].
Explanation:
Hello there!
In this case, according to the described chemical reaction between sodium carbonate and tin nitrate, we can write the undergoing chemical reaction:
[tex]2Na_2CO_3+Sn(NO_3)_4\rightarrow Sn(CO_3)_2+4NaNO_3[/tex]
Thus, we notice that the products are strontium carbonate and sodium nitrate, whose formulas are [tex]Sn(CO_3)_2[/tex] and [tex]NaNO_3[/tex] respectively.
Best regards!
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.
Considering change of state descriptions, select the name of the change of state for when energy is absorbed. Group of answer choices sublimation freezing condensation deposition
Answer: Sublimation
Explanation:
Sublimation : It is a process in which a solid directly changes to gaseous phase by providing heat.
Freezing is a process in which a liquid changes into solid phase when allowed to cool.
Condensation is a process in which a gas changes into liquid phase when allowed to cool.
Deposition is a process in which a gas deposits as solid phase when allowed to cool.
Thus change of state where energy is absorbed is sublimation.
Bryan is doing a science experiment on the stomata of plants. Bryan has a tomato plant. He uses wax to cover all the stomata on the leaves of the plant. After five days, Bryan observes that the plant is wilting. What is the best explanation for Bryan’s observation?
A. The plant released too much water into the air B. The plant was unable to carry out transpiration. C. Condensation could not occur on the leaves of the plant.
D. The plant was unable to take in water through its leaves
Answer: The answer is B
The most adequate explanation for the observation done by Bryan would be:
B). The plant was unable to carry out transpiration.
Stomata are characterized as the "tiny pores present in a leaf's epidermis which allows the gas or water vapor to pass."In the given experiment, Bryan has covered these pores which will prevent the process of photosynthesis to take place. This will result in the failure of the transpiration process in the plant to take place and its associated processes as well.
Thus, option B is the correct answer.
Learn more about "Experiment" here:
brainly.com/question/11256472
how to calculate relative abundance of copper isotopes
Answer: Atomic mass (Cu) = (x)(63.0 amu) + (1 – x)(65.0 amu) = 63.5 amu 63.0x + 65 – 65.0x = 63.5 –2x = –1.5 x = 0.75 The percent abundance of each isotope is 75.0 % (Cu-63) and 25.0 % (Cu-65).
Explanation: As you know, the average atomic mass of an element is determined by taking the weighted average of the atomic masses of its naturally occurring isotopes.
Simply put, an element's naturally occurring isotopes will contribute to the average atomic mass of the element proportionally to their abundance.
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!!!
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:
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