Answer:
15 days
Explanation:
Given half-life = 5 days => k = 0.693/half-life = 0.693/5 days⁻¹
A = A₀e^-k·t => t = ln(A/A₀) / -k = ln(1/8) / -0.1386 days⁻¹ = 15 days
The element with half life of 5 days have the decay constant of 0.1386 dy⁻¹ will take 15 days to decay to its 1/8th part of initial amount.
What is half life ?Heavy unstable radioactive isotopes undergo nuclear decay by the emission of charged particles. Nuclear decay is a first order reaction.
Thus, the decay constant k = 1/t ln W0/Wt
where t is the time of decay, W0 be the initial amount and Wt be the amount after time t.
The half life of the element = 5 days.
decay constant = 0.693/t1/2
k = 0.693/5 days = 0.1386 days⁻¹.
The time taken to decay to 1/8th of its original amount is calculated as follows:
t = 1/k ln Wo/(Wo/8 )
= ln 8/0.1386 days⁻¹
= 15 days.
Therefore, the days before the element decay to its 1/8th of original amount is 15 days.
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At constant pressure for which of the reactions shown below should Delta H be greater than Delta E°?
1.2 SO2(g) + O2(g) - 2 SO3(g)
II. C5H12(9) + 8 O2(g) - 5 CO2(g) + 6 H20(1)
III. H2(g) + Br2(g) → 2 HBr(9),
IV. N204(9) - 2 NO2(g)
Answer: [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex] has higher value of [tex]\Delta H[/tex] than [tex]\Delta E[/tex]
Explanation:
The realtion between enthalpy change and internal energy change is:
[tex]\Delta H=\Delta E+\Delta n_gRT[/tex]
where,
= enthalpy of the reaction
= internal energy of the reaction
[tex]\Delta n_g[/tex] = change in the gaseous moles of the reaction = Moles of product - Moles of reactant
R = gas constant
T = temperature
1. [tex]2SO_2(g)+O_2(g)\rightarrow 2SO_3(g)[/tex]
[tex]\Delta n_g[/tex] = 2-3 = -1
2. [tex]C_5H_{12}(g)+8O_2(g)\rightarrow 5CO_2(g)+6H_2O(l)[/tex]
[tex]\Delta n_g[/tex] = 5-9 = -4
3. [tex]H_2(g)+Br_2(g)\rightarrow 2HBr(g)[/tex]
[tex]\Delta n_g[/tex] = 2-2 = 0
4. [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex]
[tex]\Delta n_g[/tex] = 2-1 = 1
Thus reaction . [tex]N_2O_4(g)\rightarrow 2NO_2(g)[/tex] has higher value of [tex]\Delta H[/tex] than [tex]\Delta E[/tex]
At constant pressure the given reaction that shows ΔH would be greater than ΔE is;
IV); N₂0₄(g) → 2NO₂(g)
In chemistry, he meaning of ΔH and ΔE are;
- ΔH means the change in enthalpy, which is heat content.
- ΔE means the change in energy of a system.
Now, for a closed system the relationship between ΔH and ΔE is given by;
ΔH = ΔE + PΔV
where PΔV = ΔnRT
Thus; ΔH = ΔE + ΔnRT
where Δn = number of moles of product in the gaseous state - number of moles of reactants.
Thus, if Δn is negative, then ΔE would be greater than ΔH but if Δn is positive, then ΔH would be greater than ΔE
I) 2SO₂(g) + O₂(g) ⇒ 2SO₃(g)
number of moles of product = 2
number of moles of reactants = 2 + 1 = 3
Δn = 2 - 3
Δn = -1 and so ΔE would be greater than ΔH
II) C₅H₁₂(g) + 8O₂(g) ⇒ 5CO₂(g) + 6H₂0(l)
number of moles of product = 5 (6 is not used because water is in liquid and not gas)
number of moles of reactants = 8 + 1 = 9
Δn = 5 - 9
Δn = -4 and so ΔE would be greater than ΔH
III) H₂(g) + Br₂(g) → 2HBr(g)
number of moles of product = 2
number of moles of reactants = 1 + 1 = 2
Δn = 2 - 2
Δn = 0 and so ΔE would be equal to ΔH
IV) N₂0₄(g) → 2NO₂(g)
number of moles of product = 2
number of moles of reactants = 1
Δn = 2 - 1
Δn = +1 and so ΔH would be greater than ΔE
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A falling book in mid-air has___
A. both potential and kinetic energy
B. only kinetic energy
C. chemical energy
D. only potential energy
The potential and kinetic energy of a falling book is present. Kinetic energy is indeed the force driving motion, manifested in the motion of a particle, an object, or a collection of particles.
The correct answer is A
Where is the lack of kinetic energy located?Kinetic energy is the term for the energy present in an object in motion. Examples of velocity include your movement as you walk down the street and the planet's rotation around the sun. The formula for kinetic energy is as follows: K.E. is equal to half of an object's mass times its square velocity, or m/v2.
How come kinetic energy is so crucial?The capacity of kinetic energy to perform work is perhaps its most significant quality. The force applied to that of an object when it is moving is referred to as work. This intimate relationship between work and energy makes them go together.
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which of these is the smallest unit?
ds
ks
cs
ms
Answer:
ks
Explanation:
Is it right
In bulk, jelly beans cost 18 cents per ounce.
What is the cost of the jelly beans in dollars per pound?
Explanation:
One pound is equal to 16 ounces. One pound of jelly beans cost $2.88p
Answer:
$2.88
Explanation:
What type of weathering causes mineral. composition of rocks to change?
A:chemical weathering
B:General weathering
C:Mechanical weathering
D:Permeable weathering
Answer:
Chemical weathering
Explanation:
What mass of Cu(s) is electroplated by running 19.5 A of current through a Cu2 (aq) solution for 4.00 h
Answer:
92.46 g
Explanation:
The reaction is
[tex]Cu^{2+}+2e^-\rightarrow Cu[/tex]
I = Current = 19.5 A
t = 4 hours = [tex]4\times 60\times 60=14400\ \text{s}[/tex]
F = Faraday constant = 96485.33 C/mol
Molar mass of copper = 63.546 g/mol
Charge is given by
[tex]Q=It\\\Rightarrow Q=19.5\times 14400\\\Rightarrow Q=280800\ \text{C}[/tex]
Moles of electrons is given by
[tex]\dfrac{Q}{F}=\dfrac{280800}{96485.33}\\ =2.91\ \text{mol}[/tex]
Moles of copper is
[tex]\dfrac{1}{2}\times \dfrac{Q}{F}=\dfrac{1}{2}\times 2.91\\ =1.455\ \text{mol}[/tex]
Mass of copper would be
[tex]\text{Moles}\times \text{Molar mass of copper}=1.455\times 63.546\\ =92.46\ \text{g}[/tex]
The mass of copper electroplated is 92.46 g.
you can answer this for free but im not asking im just saying- why does baby donald trump cartoon with out the funny faces look like boss baby- please dont tell me boss baby is donald trump it would ruin me
Answer:
who knows..
Explanation:
Answer:
oh wow- i-
Explanation:
Models can represent systems
and processes.this is a true or false question
Answer:
True
Explanation:
Hope this helps! :)
Answer:
This is True.
Explanation:
During a chemical reaction, how do the substances that form differ from the substances that react?
Choose the most electronegative atom from the following: K, Mg, As, CI
Potassium (K)
Chlorine (CI)
Arsenic (As)
Magnesium (Mg)
Answer:
Cl
Explanation:
Electronegativity increases as you move up and to the right of the periodic table. For example, Florine is the most electronegative element.
Two gas jars are connected to each other, but they are separated by a closed valve. One gas jar contains oxygen, and the other is empty. What will happen when the valve is opened? (3 points)
a
Oxygen molecules will remain in their original jar because of the very high density of the oxygen molecules.
b
Oxygen molecules will remain in their original jar because there is enough space in the original jar.
c
Oxygen molecules will spread evenly throughout both jars because of weak intermolecular forces.
d
Oxygen molecules will spread through both jars because of the high molecular weight of oxygen.
Answer:
d) Oxygen molecules will spread through both jars because of the high molecular weight of oxygen.
Explanation:
Oxygen molecules will spread evenly throughout both jars because of weak intermolecular forces.
Intermolecular forces hold the molecules of matter together in a particular state of matter.
Gases have the weakest intermolecular forces between them. As such, the molecules of gases are isolated from each other and they move at very high velocities.
Due to weak intermolecular forces between the molecules of oxygen gas, when the valve between the two jars is opened, oxygen gas spreads evenly throughout the both jars.
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CAN you pleaaaase solve this? please please please
Answer:
115.2ml of water should be added.
Explanation:
We start with 46.2ml of 1.396M sugar solution;
We want to end up with a 0.56M sugar solution;
Finding the number of moles in the sugar solution to begin with:
moles of sugar in solution initially = 46.2 × 1.396 = 64.4952
Vd = volume of desired solution (i.e. 0.56M solution)
w = volume of water added
Vd = (46.2 + w)
Using the mol = vol' × conc'n equation:
64.4952 = Vd × 0.56
Vd = 64.4952/0.56
Vd = 115.17
46.2 + w = 115.17
w = 115.17 - 46.2
w = 68.97ml
In an atomic model, what particals are found inside the nucleas of an atom. Thanks
Answer:
protons and nuetrons
Explanation: protons have a positive charge and nuetrons which have no charge together the make up the middle of an nuclues in a atom. i may be incorrect please tell me if i am
What is the correct formula that would result from the combination
of the two ionic species?
The correct formula : BeSO₄
Further explanationChemical formula shows the composition number of the constituent atoms
Polyatomic ion consists of 2 or more ions
The equal charge of the two ions will cancel each other out, while the different charges of the two ions will be crossed each other
Be²⁺ (monatomic ion) has a positive charge of +2, while SO₄²⁻ (polyatomic ion) has a negative -2 charge, so that the two charges with the same magnitude but with different charges cancel each other out so that the compound form is BeSO4
Cu+2AgNO 3 Cu(NO 3 ) 2 +2Ag what are the reactants
Answer:
Cu + 2AgNo3 is the reactants
Which type of drug commonly marketed to consumers does not require a prescription?
A. antidepressant
B. blood pressure medication
C. pain reliever
Answer:
pain reliever
Explanation:
What is the percent yield for carbon dioxide if 10.0 grams of carbon
monoxide yielded 12.81 grams of carbon dioxide from the reaction
below?
2 CO + O2 → 2 CO2
The percent yield : 81.5%
Further explanationPercent yield is the compare of the amount of product obtained from a reaction with the amount you calculated
General formula:
Percent yield = (Actual yield / theoretical yield )x 100%
An actual yield is the amount of product actually produced by the reaction. A theoretical yield is the amount of product that you calculate from the reaction equation according to the product and reactant coefficients
Reaction
2CO+O₂⇒2CO₂
mol CO(MW=28,01 g/mol)
[tex]\tt \dfrac{10}{28.01}=0.357[/tex]
mass CO₂ (theoretical)(MW=44,01 g/mol)
[tex]\tt 0.357\times 44.01=15.712~g[/tex]
the percent yield :
[tex]\tt \dfrac{12.81}{15.712}\times 100\%=81.5\%[/tex]
Calculate the average atomic mass of an element containing 39.9% of atoms with a mass of 69 amu and 60.1% of atoms with a mass of 71 amu. Show your work for credit and round your answer to one decimal place.
Answer:
70.202 amu
Explanation:
From the question given above, the following data were obtained:
Isotope A:
Abundance (A%) = 39.9%
Mass of A = 69 amu
Isotope B:
Abundance (B%) = 60.1%
Mass of B = 71 amu
Average atomic mass =?
The average atomic mass of the element can be obtained as follow:
Average atomic mass = [(Mass of A × A%)/100] + (Mass of B × B%)/100]
= [(69 × 39.9)/100] + [(71 × 60.1)/100]
= 27.531 + 42.671
= 70.202 amu
Therefore, the average atomic mass of the element is 70.202 amu
Perform the following calculation with the
correct number of significant figures.
12.62 +2.3 + 0.34 = ?
What is the answer please help
Answer: C
Explanation:
there should be 2 molecules which leaves A and C. But there should be 1 white circle and 3 black circles which means C is the right answer
what
your events made Gautam Buddha to
go in search of the truth?
Answer:
The Buddha (also known as Siddhartha Gotama or Siddhārtha Gautama[note 3] or Buddha Shakyamuni) was a philosopher, mendicant, meditator, spiritual teacher, and religious leader who lived in Ancient India (c. 5th to 4th century BCE).[5][6][7][note 4] He is revered as the founder of the world religion of Buddhism, and worshipped by most Buddhist schools as the Enlightened One who has transcended Karma and escaped the cycle of birth and rebirth.[8][9][10] He taught for around 45 years and built a large following, both monastic and lay.[11] His teaching is based on his insight into duḥkha (typically translated as "suffering") and the end of dukkha – the state called Nibbāna or Nirvana.
The Buddha was born into an aristocratic family in the Shakya clan but eventually renounced lay life. According to Buddhist tradition, after several years of mendicancy, meditation, and asceticism, he awakened to understand the mechanism which keeps people trapped in the cycle of rebirth. The Buddha then traveled throughout the Ganges plain teaching and building a religious community. The Buddha taught a middle way between sensual indulgence and the severe asceticism found in the Indian śramaṇa movement.[12] He taught a spiritual path that included ethical training and meditative practices such as jhana and mindfulness. The Buddha also critiqued the practices of Brahmin priests, such as animal sacrifice.
A couple of centuries after his death he came to be known by the title Buddha, which means "Awakened One" or "Enlightened One".[13] Gautama's teachings were compiled by the Buddhist community in the Suttas, which contain his discourses, and the Vinaya, his codes for monastic practice. These were passed down in Middle-Indo Aryan dialects through an oral tradition.[14][15] Later generations composed additional texts, such as systematic treatises known as Abhidharma, biographies of the Buddha, collections of stories about the Buddha's past lives known as Jataka tales, and additional discourses, i.e, the Mahayana sutras.
Explanation:
Consider the following reaction. MgCl2(aq)+2NaOH(aq)⟶Mg(OH)2(s)+2NaCl(aq) A 187.0 mL solution of 0.103 M MgCl2 reacts with a 33.58 mL solution of 0.839 M NaOH to produce Mg(OH)2 and NaCl. Identify the limiting reactant.
Answer:
NaOH is the limiting reactant and MgCl2 is in excess.
Explanation:
let's calculate the mole of each reactant.
number of moles of MgCl2 = [tex]\frac{187}{1000} L* 0.103 mol / L =0.01926 mol\\[/tex]
number of moles of NaOH = [tex]\frac{33.58 }{1000}L * 0.839 mol/L =0.0282 mol[/tex]
as per the reaction , 1 mol of Magnesium choloride reacts with 2 moles of NaOH
hence 0.01926 needs 0.01926x2= 0.03852 moles of NaOH , but there are only 0.0282 moles of NaOH available .
The limiting reactant for the reaction between 187.0 mL solution of 0.103 M MgCl₂ and 33.58 mL solution of 0.839 M NaOH is NaOH
We'll begin by calculating the number of mole of MgCl₂ and NaOH present in the solution.
For MgCl₂:Volume = 187 mL = 187 / 1000 = 0.187 L
Molarity = 0.103 M
Mole of MgCl₂ =?Mole = Molarity x Volume
Mole of MgCl₂ = 0.103 × 0.187
Mole of MgCl₂ = 0.019 mole For NaOH:Volume = 33.58 mL = 33.58 / 1000 = 0.03358 L
Molarity = 0.839 M
Mole of NaOH =?Mole = Molarity x Volume
Mole of NaOH = 0.839 × 0.03358
Mole of NaOH = 0.028 moleFinally, we shall determine the limiting reactant. This can be obtained as follow:
MgCl₂ + 2NaOH —> Mg(OH)₂ + 2NaCl
From the balanced equation above,
2 moles of NaOH required 1 mole of MgCl₂.
Therefore, 0.028 mole of NaOH will require = [tex]\frac{0.0282}{2}\\[/tex] = 0.014 mole of MgCl₂
From the calculations made above, we can see that only 0.014 mole of MgCl₂ out of 0.019 mole reacted completely with 0.028 mole of NaOH.
Therefore, NaOH is the limiting reactant and MgCl₂ is the excess reactant.
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In which of the following elements is the least
amount of energy required to remove the most
loosely bound electron from an atom in the gaseous
state?
A) Sr
B) Ar
C) Al
D C
Answer:
A) Sr
Explanation:
Strontium will require the least amount of energy to remove the most loosely bound electrons from its atom in gaseous state.
This parameter is known as the ionization energy. It is defined as the readiness of an atom to lose an electron.
Metals in group 1 and 2 generally have very low ionization energy due to their large electropositivity The more electropositive a metal is, the lower its ionization energy. This is the reason why strontium will have the least ionization energy.Which of the following biogeochemical cycles does not contain a molecule in a gaseous state?
A 1.59 mol sample of Kr has a volume of 641 mL. How many moles of Kr are in a 4.41 L sample at the same temperature and pressure?
Answer:
The correct answer is 10.939 mol ≅ 10.94 mol
Explanation:
According to Avogadro's gases law, the number of moles of an ideal gas (n) at constant pressure and temperature, is directly proportional to the volume (V).
For the initial gas (1), we have:
n₁= 1.59 mol
V₁= 641 mL= 0.641 L
For the final gas (2), we have:
V₂: 4.41 L
The relation between 1 and 2 is given by:
n₁/V₁ = n₂/V₂
We calculate n₂ as follows:
n₂= (n₁/V₁) x V₂ = (1.59 mol/0.641 L) x 4.41 L = 10.939 mol ≅ 10.94 mol
The number of moles is 10.94 mol.
The calculation is as follows:
As per the Avogadro gases law, the no of moles at the same pressure & temperature should be proportional to the volume.The following formula should be used:
[tex]n_1\div V_1 = n_2\div V_2\\\\n_2= (n_2\div V_1) \times V_2\\\\ = (1.59 mol\div 0.641 L) \times 4.41 L[/tex]
= 10.939 mol
= 10.94 mol
Therefore we can conclude that the number of moles is 10.94 mol.
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What is the frequency of a photon that has a wavelength of 754 um?
Answer:
Explanation:
What is the frequency of a photon that has a wavelength of 754 um?
which of the following disease is not transmitted by mosquito
(a) Dengue (b) Malaria (c)Bain fever (d)Pneumonia
pneumonia is not transmitted by mosquito
Introduction:
Briefly describe the physical behavior you investigated.
What is the exploration about?
What are you trying to discover?
Relate to any previous work.
Use new vocabulary words, if you can.
Answer: im not sure if this is the best answer but i wrote, "This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."
Explanation: hope this helps.
This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."
Thus, For persons with autism, life can be incredibly stressful at times, and their behaviour may be an indication of their utter exasperation or suffering in reaction to a variety of pressures.
Some people struggle with the idea of time and sequencing, thus this can involve onerous tasks, meeting new people, experiencing unpleasant sensory stimuli, a change in routine, switching activities, or having to wait for anything.
The individual may have realized how effective their actions could be in influencing their environment. A behaviour that was initially a reaction to physical discomfort or frustration may later develop into a strategy for evading a request or getting rid of an uncomfortable circumstance.
Thus, This exploration is about how the volume of a gas varies with temperature, and what the effect does to the gas and what effect it has on the results."
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The question is Incomplete, the complete question is:
Briefly describe the physical behavior?
What is the exploration about?
What are you trying to discover?
Relate to any previous work.
Use new vocabulary words, if you can.
In the exploration, I was a bird trying to eat bugs placed in different backgrounds. Each bug was adifferent color, and the color either matched or stood out against the background. What I wastrying to discover was how creatures adapted to their environment and if blending in with theirenvironment helped them or hindered them. I discovered that yes, blending in with theenvironment helps creatures survive.
Please help!!!Which statement accurately describes relationship between weight and mass? If the picture is black just don’t answer
Answer:
A
Explanation:
Mass is a raw measurement, weight is effected by gravity
Question 10 of 10 Which of the following compounds is the most stable? A. Agci B. LICI C. AlCl3 D. CuCl2
Answer:
b
Explanation: