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.
Where are electrons found in an atom?
Answer:
outside the nucleus
Explanation:
How many mL of 0.715 M HCl is required to neutralize 1.25 grams of sodium carbonate? (producing carbonic acid)
I really couldn't find the answer since molarity and volume for sodium carbonate are not given.
I will mark the correct answer with steps as best answer.
Answer:
34 mL
Explanation:
We'll begin by calculating the number of mole in 1.25 g of sodium carbonate, Na₂CO₃. This can be obtained as follow:
Mass of Na₂CO₃ = 1.25 g
Molar mass of Na₂CO₃ = (23×2) + 12 + (16×3)
= 46 + 12 + 48
= 106 g/mol
Mole of Na₂CO₃ =?
Mole = mass /molar mass
Mole of Na₂CO₃ = 1.25 / 106
Mole of Na₂CO₃ = 0.012 mole
Next, we shall determine the number of mole HCl needed to react with 0.012 mole of Na₂CO₃.
The equation for the reaction is given below:
Na₂CO₃ + 2HCl —> H₂CO₃ + 2NaCl
From the balanced equation above,
1 mole of Na₂CO₃ reacted with 2 moles of HCl.
Therefore, 0.012 mole of Na₂CO₃ will react with = 0.012 × 2 = 0.024 mole of HCl.
Next, we shall determine the volume of HCl required for the reaction. This is illustrated:
Mole of HCl = 0.024 mole
Molarity of HCl = 0.715 M
Volume of HCl =?
Molarity = mole /Volume
0.715 = 0.024 / volume of HCl
Cross multiply
0.715 × volume of HCl = 0.024
Divide both side by 0.715
Volume of HCl = 0.024 / 0.715
Volume of HCl = 0.034 L
Finally, we shall convert 0.034 L to mL
This can be obtained as follow:
1 L = 1000 mL
Therefore,
0.034 L = 0.034 L × 1000 mL / 1 L
0.034 L = 34 mL
Therefore, 34 mL of HCl is needed for the reaction.
The amount of HCl required for counterbalancing 1.25 g of Na2CO3(Sodium Carbonate) would be:
- [tex]34 ml[/tex]
Given that,
Mass of Na2CO3 [tex]= 1.25 g[/tex]
To find the Moles of Na2CO3, we will find the molar mass of Na2CO3,
Molar Mass of or Na2CO3 [tex]= 106 g/mol[/tex]
So,
Moles of Na2CO3 [tex]= mass /molar mass[/tex]
[tex]= 1.25/106[/tex]
[tex]= 0.012 mol[/tex]
To determine the quantity of HCl required to display the reaction with 0.012 mol of Na2CO3
[tex]Na_{2} CO_{2} + 2HCl[/tex] → [tex]H_{2}CO_{3} + 2NaCl[/tex]
While balancing the equation, we know that [tex]0.012[/tex] × [tex]2 = 0.024 mole of HCl[/tex] is necessary to process the reaction.
Now,
As we know,
HCl moles [tex]= 0.024[/tex]
Molarity of HCl [tex]= 0.715 M[/tex]
∵ Quantity of HCl required = Moles/Molarity
[tex]= 0.024 / 0.715[/tex]
[tex]= 0.034 l[/tex] [tex]or 34ml[/tex]
Thus, 34 ml is the correct answer.
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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:
A 1.om sample of dry air at
at 25°c at 786mmHg contains 0.925g Nitrogen Plus other gases including oxygen, argon and carbon dioxide. what is the partial pressure of Na with the air sample.
Answer:
Is the question not supposed to be what is the partial pressure of Nitrogen not Sodium
Calculate the percent composition of C in carbon dioxide.
Answer:
27.27%
Explanation:
The compound FeCl3 Is made of.
Answer:
iron and chlorine
Explanation:
Help it’s about Binary compounds and transition metals
Answer:
Cr 6+ & SO4 2-
Explanation:
Sulfate is a polyatomic ion that has a charge of 2-. There are three of them in the chemical formula so it equates to a 6- total charge. Thus, chromium must have a 6+ charge to give the compound a neutral charge.
Suppose you have a 1:1:1 by weight mixture of three solid compounds, salicylic acid 4-nitroaniline naphthalene. You dissolve 1 gram of this mixture in diethyl ether, and place a tiny drop of the ether solution on a TLC plate. After developing the TLC plate, you see three spots. Which compound would would you expect to have the largest Rf value
Answer:
The correct answer is - 4-nitroaniline.
Explanation:
It is given that all three solid compounds salicylic acid + 4-nitroaniline + naphthalene are equal in the ratio in the mixture and then 1 gram of this mixture is dissolved in the diethyl ether and run a drop of the solution on TLC plate. This plate shows three spots.
The salicylic acid and naphthalene would stay dissolved in the diethyl ether solution due to the 4-nitroaniline could be extracted by adding aqueous acid and involve in the aqueous layer and thus spot of 4-nitroaniline would be with largest Rf value.
Choose all the answers that apply.
The atmosphere:
is made mostly of nitrogen
can be used to transmit radio signals
traps heat from the sun
protects the earth from harmful radiation
is important in the water cycle
Answer:1 2 and 4
Explanation:
A 72.0 g sample of an organic solid is dissolved in 180mL of water. The solid is extracted using one 60 mL extraction in the first extraction of an organic solvent which has a partition (distribution) coefficient with water of 10. The first extraction removed 55.4 g of solid from water. What are the numbers that need to go in box A and B to calculate the volume of solvent (y) that would be necessary to remove an additional 7.0g from the remaining sample dissolved in water. You DON'T have to complete the calculation to solve for y.
Answer:
[tex]V_{7.0}\approx 235ml[/tex]
Explanation:
From the question we are told that
mass of sample [tex]M=72.0 grams[/tex]
volume of water [tex]V=180 mL[/tex]
volume for extraction [tex]V'=60mL[/tex]
partition (distribution) coefficient water [tex]d=10[/tex]
initial extraction removal [tex]x=55.4g[/tex]
Generally the equation for the weight of sample [tex]x_n[/tex] is mathematically given by
[tex]x_n=x*(\frac{DV}{DV+V'})^n[/tex]
[tex]x_n=55.4(\frac{10*180}{10*180+60})^1[/tex]
[tex]x_n=53.613g[/tex]
Generally the weight extracted [tex]x_e[/tex] is therefore
[tex]w_e=x-x_n[/tex]
[tex]w_e=55.4-53613[/tex]
[tex]w_e=1.787[/tex]
[tex]w_e=1.787[/tex] is extracted with 60ml solvent .
Therefore volume of solvent (y) that would be necessary to remove an additional 7.0g
[tex]V_{7.0}=\frac{60}{1.767}*7[/tex]
[tex]V_{7.0}=235.030ml[/tex]
[tex]V_{7.0}\approx 235ml[/tex]
Question 6 of 10
How much energy is required to vaporize 2 kg of gold? Use the table below
and this equation: Q = mLvapor
Substance
Latent Heat
Fusion
(melting)
(kJ/kg)
Melting
Point
(°C)
Latent Heat
Vaporization
(boiling) (kJ/kg)
Boiling
Point
(°C)
Aluminum
400
660
1100
2450
Copper
207
1083
4730
2566
Gold
628
1063
1720
2808
Helium
52
-270
21
-269
Lead
24.5
327
871
1751
Mercury
11.4
-39
296
357
Water
335
0
2256
100
Answer: Q = mlvap
Q = (2 kg)(1 kmol/197 kg)(1,000 mol/1 kmol)
Q = 10.15 kJ
2126 joules of energy in form of thermal energy is required to vaporize 2 kg of gold.
What is thermal energy?Thermal energy is defined as a type of energy which is contained within a system which is responsible for temperature rise.Heat is a type of thermal energy.It is concerned with the first law of thermodynamics.
Thermal energy arises from friction and drag.It includes the internal energy or enthalpy of a body of matter and radiation.It is related to internal energy and heat .It arises when a substance whose molecules or atoms are vibrating faster.
These vibrating molecules and atoms collide and as a result of which heat is generated in a substance , more the collision of particles , higher is the thermal energy.
Amount of heat is calculated as, Q=2×1063 =2126 joules as per the given formula.
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Use the following Balanced Equation to complete the question: 2 Al + 6 HBr → 2 AlBr3 + 3 H2
If you have 10 moles of Al how many moles of H2 can be produced?
*Will give Brainly!*
When NH3(g) reacts with O2(g) to form N2O(g) and H2O(l), 342 kJ of energy are evolved for each mole of NH3(g) that reacts. Write a balanced thermochemical equation for the reaction with an energy term in kJ as part of the equation.
Answer: [tex]2NH_3(g)+2O_2(g)\rightarrow N_2O(g)+3H_2O(l)+684kJ[/tex]
Explanation:
The skeletal thermochemical equation for the reaction is:
[tex]NH_3(g)+O_2(g)\rightarrow N_2O(g)+H_2O(l)+342kJ[/tex]
The balanced thermochemical equation for the reaction is:
[tex]2NH_3(g)+2O_2(g)\rightarrow N_2O(g)+3H_2O(l)+684kJ[/tex]
When 1 mole of [tex]NH_3[/tex] reacts with oxygen , heat released = 342 kJ
Thus when 2 moles of [tex]NH_3[/tex] reacts with oxygen , heat released = [tex]\frac{2}{1}\times 342 kJ=684kJ[/tex]
Compare the number of moles calculated in parts a) 0.03 and b). 0.064. Which of the three possible reactions discussed is consistent with these results?
Answer:don’t click link ur gonna get ur info taken
Explanation:
what is the mass concentration in ppm of NaCl of 0.01% mass/mass
A-10
B-100
C-10^3
D-10^4
E-10^5
Answer:
B-100
Explanation:
ppm is an unit of concentration that could be defined as the mass in mg of solute (In this case, NaCl) per kg of solution.
Now, a solution of NaCl that is 0.01% by mass, contains 0.01g of NaCl in 100g of solution.
To solve this question, we must convert the mass of NaCl to mg and the mass of solution to kg:
Mass NaCl:
0.01g * (1000mg / 1g) = 10mg
Mass Solution:
100g * (1kg / 1000g) = 0.10kg
The ppm are:
10mg / 0.10kg =
100ppm
Right answer is:
B-100How many moles of NaOH are contained in 56.0 mL of a 2.40 M solution of 1 point
NaOH in water? (**Use only numerical answers with 3 significant figures.
The units are given in the question.)
Your answer
Answer:
1.34 mol
Explanation:
Molarity, which is the molar concentration of a solution, can be calculated by dividing the number of moles (n) by the volume (V).
That is;
Molarity (M) = n/V
According to the information provided in this question;
M = 2.40M
V = 56.0 mL = 56/1000 = 0.056 L
Since molarity = n/V
number of moles = M × V
n = 0.056 × 24
n = 1.34 mol
You have a bag of chips at a constant pressure of 1 Atm with a volume of .5 L and a temperature of 10C. The bag is left under the sun for a couple of hours at a temperature of 35 C, what will its new volume be?
Answer:
0.54 L
Explanation:
Given that,
Initial volume, V₁ = 0.5 L
Initial temperature, T₁ = 10°C = 283 K
Final temperature, T₂ = 35 C = 308 K
We need to find the final volume. The relation between the volume and temperature is given by :
[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{0.5\times 308 }{283}\\\\V_2=0.54\ L[/tex]
So, the new volume is 0.54 L.
How much energy ( in joule ) does the Sun emit in one day (24 hours)? I've previously answered with 3.32, but it was incorrect. Please help thanks.
It is about 3.86 which is 10⁶⁶ watts
Answer:
410 quintillion Joules or 430,000,000,000,000,000,000 Joules
A buffered solution _______. Select the correct answer below: fails to keep hydronium and hydroxide ion concentrations nearly constant when strong acids or bases are added. maintains a constant or nearly constant pH when small amounts of strong acids or bases are added. acts to keep the hydroxide ion concentration nearly constant. acts to keep the hydronium ion concentration nearly constant.
The correct option for the given question about Buffer Solution is Option B) which is maintains a constant or nearly constant pH when small amounts of strong acids or bases are added.
What is a Buffer Solution?When a little quantity of acid or base is diluted or added, the buffer solution undergoes very slight variations in its hydrogen ion concentration (pH). pH may be maintained in buffer solutions, which are mixtures of a weak acid and its conjugate base or a weak base and its conjugate acid.Acidic and alkaline buffers are the two main groups into which buffer solutions are commonly categorized.A weak acid and its salt are combined with a strong base to create an acidic buffer, which has an acidic pH.A weak base, its salt, and a strong acid are combined to create an alkaline buffer, which has a basic pH.
Thus we conclude that when weak acids or bases are supplied in small amounts, the pH remains steady or almost constant.
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Help will give brainliest no “click this link”
The longest continuous carbon chain comprises five carbon atoms connected by single bonds, so the root name will be pentane. There is a methyl group (—CH3) attached to carbon 3 (since this molecule is symmetrical, the methyl substituent will always be on carbon 3 regardless of which end you begin counting). Thus, the name of this molecule would be 3-methylpentane.
Which of the following methods of fossil formation is formed in dry areas due to a lack of moisture?
a
Mummification
b
Casts and molds
c
Amber fossil
d
Carbonization
The methods of fossil formation in dry areas due to a lack of moisture is mummification. The correct option is a.
What is mummification?Mummification is the process of deliberately drying or embalming flesh to preserve the body after death.
This typically entailed removing moisture from a deceased body and desiccating the flesh and organs with chemicals or natural preservatives such as resin.
Mummification served the purpose of keeping the body intact so that it could be transported to a spiritual afterlife.
The body was stripped, positioned on a slanted table, and washed in natron solution (a naturally occurring salt used both as soap and a preservative).
The brain was extracted from the skull through a hole in the ethmoid bone (the bone separating the nasal cavity from the skull cavity).
Thus, the correct option is A.
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Is chemistry required to get into speech language pathology?
Answer:
As of right now (4-7-2021), the physical science requirement for the SLP certificate must be met by completing coursework in the areas of either chemistry or physics.
.35L sample of helium gas is collected at 295 K and 0.98 ATM what volume would this gas occupy at STP
Answer:
0.3857 litres is the answer
wich strong nucleophil h2s or water??and why??
According to my notes, nucleophilicity order is directly proportional to basicity order in an aprotic medium, and is inversely proportional to basicity order in protic medium. And H2O is a stronger base than H2S, so it should be the strong nucleophile, but the answer is given as H2S is the stronger nucleophile.
hope this helped, good luck <3
Identify the most and the least basic compound in each of the following sets. Leave the remaining answer in each set blank. a) Sodium acetate: _______ Ammonia: _______ Sodium ethoxide: _______ b) Sodium acetate: _______ Sodium chloroacetate: _______ Sodium fluoroacetate: _______ c) Sodium acetate: _______ Sodium methoxide: _______ Sodium phenoxide:
Answer:
The correct answer is -
a) Sodium acetate: least Ammonia: _______ Sodium ethoxide: most
b) Sodium acetate: most Sodium chloroacetate: _______ Sodium fluoroacetate: least
c) Sodium acetate: least Sodium methoxide: most Sodium phenoxide:
Explanation:
A) In this case the basicity can be found by the stability of the base, Sodium acetate is the most stable base due to resonance stabilization of acetate anion. Sodium acetate is the least basic as the lone pair of electrons involved in the resonance here. An ethoxide ion has more electrons to donate an electron pair easily.
Thus, the correct answer is - Sodium acetate is the least basic while sodium ethoxide is the most basic.
B) Fluroacetate gives a very strong acid and the acetate gives the least strong acid among all three as described in case of a), thus, the most basic is acetate and the least is fluoroacetate.
]C) comparing the acidity of the acids formed by the addition of a proton to the anions is an easy and correct way to find the basicity of compounds.
Acetate ion adds a proton ⇒ acetic acid
methoxide adds a proton ⇒ methanol
phenoxide ion adds proton ⇒ phenol
As it is known that the stronger the acid, the weaker is the conjugate base formed by the loss of the proton.
acetic acid is the strongest acid because it can easily give up its proton to form acetate. Methanol is the weakest among all three and hence methoxide anion is the strongest base.
Thus, the correct answer is - sodium acetate is the least basic while sodium methoxide is the most basic.
In a sample of neon, carbon, and oxygen gas, the total pressure is 9 atm.
The partial pressure of neon is 2 atm and the partial pressure of oxygen is 2
atm. What is the partial pressure of carbon?
9 atm
3 atm
5 atm
4 atm
Answer:
5 atm
Explanation:
add boh partial pressures and subtract from total pressure
Consider a solution which is 0.10M in NH3 and 0.20M in NH4Cl. Choose ALL of the following that are false. If a small amount of NaOH is added, the pH becomes slightly more basic. If HCl is added, the H ions react with the NH3. If a small amount of HCl is added, the pH becomes slightly more basic. If NaOH is added, the OH- ions react with the NH3. If NH4NO3 is added, the pH becomes more basic.
Answer:
The incorrect or the false options are -
(B) - If NH4NO3 is added, the pH becomes more basic.
(D) - If a small amount of HCl is added, the pH becomes slightly more basic.
(E) - If NaOH is added, the OH- ions react with the [tex]NH_3[/tex].
Explanation:
The given solution the buffer basic .
When a small amount of either is added, the hydrogen ion reacts with the ammonium ion, raising the pH slightly.When a small amount of HCl is added, the hydronium ion reacts with the ammonia, raising the pH slightly.Therefore , the options A ( If a small amount of NaOH is added, the pH becomes slightly more basic.) and C ( If HCl is added, the H+ ions react with the NH3.) All other B , D , E are false .
Help me I'm desperate :( no links or u will be reported
Answer:
Here is the answer from somewhere in the internet
Helllllp me please
Part D ends with neon Express your answer as an integer. 20
Answer:
attach file please
I a doing an exam in science pls help.
What type of energy comes from the motion of tiny particles of matter?
Answer:
heat
Explanation:
Answer:
Thermal Energy
Explanation:
