Explanation:
From the question given above, the following data were obtained:
Half-life (t½) = 9.7 days
Time (t) = 60 days
Percentage remaining after 60 days =?Next, we shall determine the number of half-lives that has elapsed. This can be obtained as follow:
Half-life (t½) = 9.7 days
Time (t) = 60 days
Number of half-lives (n) =?
n = t / t½
n = 60 / 9.7Finally, we shall determine the percentage remaining. This can be obtained as follow:
Let the original amount be N₀
Let the amount remaining be N
Number of half-lives (n) = 60 / 9.7
N = N₀ / 2ⁿ
Divide both side by N₀
N/N₀ = 1/2ⁿ
N/N₀ = 1 / 2⁽⁶⁰÷⁹•⁷⁾
N/N₀ = 0.0137
Multiply by 100 to express in percentage
N/N₀ = 0.0137 × 100
N/N₀ = 1.37%Therefore, the percentage remaining after 60 days is 1.37%
NOTE; N/N₀ is the fraction remaining.Learn more: https://brainly.com/question/14883322
Radon-220 undergoes alpha decay with a half-life of 55.6 s.?
Assume there are 16,000 atoms present initially and calculate how many atoms will be present at 0 s, 55.6 s, 111.2 s, 166.8 s, 222.4 s, and 278.0 s (all multiples of the half-life). Express your answers as integers separated by commas.
Calculate how many atoms are present at 50 s, 100 s, and 200 s (not multiples of the half-life).
The half life of a radioactive isotope refers to the time taken for half of the number of original number of atoms present in the sample to decay.
The equation below gives the number of atoms present at time t
[tex]N=Noe^-kt[/tex]
N = Number of atoms present at time t
No = Number of atoms initially present
k = decay constant
t = time taken
Given that;
t1/2 = 0.693/k
where t1/2 = half life
k = 0.693/t1/2
k = 0.693/ 55.6 s
k = 0.0125 s-1
Substituting values;
N = 16,000 e^-0.0125(0)
N = 16,000 atoms
At 50 s
N = 16,000 e^-0.0125(50)
= 8564 atoms
At 100 s
N = 16,000 e^-0.0125(100)
= 4584 atoms
At 200 s
N = 16,000 e^-0.0125(200)
= 1313 atoms
https://brainly.com/question/2998270
tính ΔH° của phả ứng sau ở 200°C
CO+1÷2O=CO2
ΔH°
work 10
HOMEWORK ASSIGNMENTS Content
Detai
Question 1
6.25 Points
р А.
71
Calculate AE of a gas for a process in which the gas evolves 24 J of heat and has 9 of work done on it.
A
✓
A -33)
B +33)
Gradin
-220)
D) +15)
E -15)
Question 2
6.25 Points
Answer
A
Explanation:
due to high specific heat capacity it loses heat and has low temperature
The decomposition of ammonia is: 2 NH3(g) ⇌ N2(g) + 3 H2(g). If Kp is 1.5 × 103 at 400°C, what is the partial pressure of ammonia at equilibrium when N2 is 0.20 atm and H2 is 0.15 atm?
Answer:
"[tex]6.7\times 10^{-4} \ atm[/tex]" is the right answer.
Explanation:
Given:
Partial pressure of [tex]N_2[/tex],
= 0.20 atm
Partial pressure of [tex]H_2[/tex],
= 0.15 atm
[tex]K_p = 1.5\times 10^3[/tex] at [tex]400^{\circ} C[/tex]
As we know,
⇒ [tex]K_p = \frac{pN_2\times pH_2^3}{pNH_3^2}[/tex]
By putting the values, we get
[tex]1.5\times 10^3=\frac{0.20\times (0.15)^3}{pNH_3^2}[/tex]
[tex]pNH_3^2 = \frac{0.000675}{1.5\times 10^3}[/tex]
[tex]=6.7\times 10^{-4} \ atm[/tex]
Please guys please answer this
Answer:
1. Because the rules will keep you safe it prevents you from getting hurt.
2.i) don't taste chemical
ii) Always wear protective gears
iii) be careful with tool
iv) wear protective gloves
Explanation:
help everyone get out quickly
Can someone teach me step by step how finding the oxidation number in this problem:
Fe in Fe(CIO2)3
Answer:
+3
Explanation:
u see sum of oxidation number in all situations have to be 0
ClO2 =-1
so Fe is +3
11. An isotope Q has 18 neutrons a mass number of 34. (a) (i) What is an isotope? An isotope is one of two or C (b) Write its electron arrangement. Mass number=34 Number of neutrons=18 Number of Protons = 34-15-16 (c) To which period and group does Q belong? Protors - Electons - Atomic number Period - Group (d) How does Q form its ion?
An isotope is an element with the same atomic number but different mass number due to differences in number of neutrons.
electron configuration is 2,8,6.
Belongs to group 6 and period group 3.
It forms an ion by accepting 2 electrons
A mixture of argon and neon gases at a total pressure of 874 mm Hg contains argon at a partial pressure of 662 mm Hg. If the gas
mixture contains 12.0 grams of argon, how many grams of neon are present?
Answer:
6.684g
Explanation:
Here, we can use the mole ratio of the gases to calculate.
We know that the mole ratio of the gases equate to their number of moles.
Firstly, we calculate the number of moles of the oxygen gas. The number of moles of the oxygen gas is equal to the mass of the oxygen gas divided by the molar mass of the oxygen gas. The molar mass of the oxygen gas is 32g/mol
Thus, the number of moles produced is 5.98/32 = 0.186875
Where do we move from here?
We know that if we place the partial pressure of oxygen over the total pressure, this would be equal to the number of moles of oxygen divided by the total number of moles. Now let’s do this.
449/851 = 0.186875/n
n =(0.186875 * 851)/449
n = 0.3542
Now we do the same for argon to get the number of moles of argon.
Firstly, we use dalton’s partial pressure law to get the partial pressure of argon. In the simplest form, the partial pressure of argon is the total pressure minus the partial pressure of oxygen.
P = 851 - 449 = 402 mmHg
We now use the mole ratio relation.
402/851 = n/0.3542
n = (402 * 0.3542) / 851
n = 0.1673
Since we now know the number of moles of argon, we can use this multiplied by the atomic mass of argon to get the mass.
The atomic mass of argon is 39.948 amu
The mass is thus 39.948 * 0.1673 = 6.684g
The idea that the behavior of the states of matter is determined by the kinetic energy and movement of their particles is called _____…
A. Sublimation Theory
B. Kinetic Movement Theory
C. Kinetic Molecular Theory
D. Van der Waals Theory
Answer:
C . Kinetic Molecular Theory
What is a litmus solution? How is it obtained?
A bond dissociation energy is A) The energy required to remove an electron from an atom. B) The energy released when an ionic compound dissociates in water. C) The energy required to break a covalent bond. D) The energy produced in a chemical reaction that breaks chemical bonds.
Answer:
The energy required to break a covalent bond
Explanation:
When a chemical bond is formed, energy is released. When a chemical bond is broken, energy is absorbed.
We define the bond dissociation energy as the energy required to break a covalent bond. The process of covalent bond cleavage is endothermic hence energy is absorbed for the process to occur.
The radioactivity due to carbon-14 measured in a piece of a wood from an ancient site was found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produced 160 counts per minute. The half-life of carbon-14, a beta emitter, is 5730 y. The age of the artifact is closest to
Answer:
The answer is "17200 years".
Explanation:
Given:
[tex]A = 20 \ \frac{counts}{minute}\\\\A_{o} = 160\ \frac{counts}{minute}[/tex]
Let the half-life of carbon-14, is beta emitter, is [tex]T = 5730\ years[/tex]
Constant decay [tex]\ w = \frac{0.693}{ T}[/tex]
[tex]= 1.209 \times 10^{-4} \ \frac{1}{year}\\[/tex]
The artifact age [tex]t= ?[/tex]
[tex]A = A_{o} e^{-wt} \\\\e^{-wt} = \frac{A}{A_{o}}\\\\-wt = \ln \frac{A}{A_{o}}\\\\= -2.079\\\\t = 1.7199 \times 10^{4} \ years\\\\\sim \ 17200\ years\\[/tex]
Write the balanced equation for the hydration of CuSO4CuSO4. Indicate the physical states using the abbreviations (ss), (ll), or (gg) for solid, liquid, or gas, respectively. Use (aqaq) to indicate the aqueous phase. Indicate appropriate charges on negative and positive ions if they are formed.
Answer:
CuSO4(s) + 5H2O(l) ----> CuSO4.5H2O(s)
Explanation:
Hydration is the process by which anhydrous CuSO4 acquires molecules of water of crystalization to form the pentahydrate.
The water of crystalization becomes attached go the crystals of the CuSO4 to form the hydrated salt.
Beginning with solid anhydrous CuSO4 we have;
CuSO4(s) + 5H2O(l) ----> CuSO4.5H2O(s)
Compounds such as butane and isobutane that have the same molecular formula but differ in the order in which the atoms are connected are called ____________
a. trans isomers
b. cis isomers
c. conventional isomers
d. constitutional isomers
Answer:
One compound, called n-butane, where the prefix n- represents normal, has its four carbon atoms bonded in a continuous chain. The other, called isobutane, has a branched chain. Different compounds that have the same molecular formula are called isomers.
Answer:
d. constitutional isomers
Explanation:
i hope it will help
What is the balanced equation for the reaction of lithium metal with fluorine gas? Li ( s ) + F ( g ) → LiF ( s ) Li ( s ) + F 2 ( g ) → LiF ( s ) 2 Li ( s ) + F 2 ( g ) → 2 LiF ( s ) Li ( s ) + F 2 ( g ) → LiF
Answer:
2Li(s) + F2(g)→2LiF(s)
Explanation:
Calculate the molarity of the following solution.
45.7 g C10H12 in 5230 mL of solution
unit:
Answer:
Molarity = Moles of solute/Volume of solution(in Litres)
Solute = C10H12
moles of solute = Mass/Molar Mass
Molar Mass of C10H12 = 10(12) + 12(1)
= 132gmol-¹
Mole = 45.7/132 = 0.346mol
Molarity = 0.346/5.23
=0.066M
When hydrogen gas reacts with oxygen gas, water vapour is formed according to the
reaction 2H2 + O2 2H2O. If 3.00 mol of hydrogen gas react with 3.00 mol
of oxygen gas, which reactant will be the reactant in excess?
Explanation:
here's the answer to the question
Select all of the statements that are true about a buffer solution. A buffer solution always changes color when the pH changes. A buffer solution reacts with basic solutions. A buffer solution has a pH of 7. A buffer solution resists small changes in pH. A buffer solution reacts with acidic solutions. At what point on the titration curve for a weak acid is the solution a buffer
Answer: A buffer solution reacts with basic solutions.
A buffer solution resists small changes in pH.
A buffer solution reacts with acidic solutions.
Explanation:
A buffer solution simply refers to an aqueous solution that consist of a mixture of a weak acid and the conjugate. From the options given, the ones application to a buffer solution include:
• A buffer solution reacts with basic solutions.
• A buffer solution resists small changes in pH.
• A buffer solution reacts with acidic solutions.
What is the biggest cause of change in Earth's systems?
A. Heat
B. Motion
C. Friction
D. Plate tectonics
Answer:
heat
Explanation:
because it's the cause of change
Answer:
heat
Explanation:
because it is a natural factor that causes the change in Earth's system
The mass of an empty flask plus stopper is 64.232g. When the flask is completely filled with water the new mass is 153.617 g. The flask is emptied and dried, and a piece of metal is added. The mass of the flask, stopper and metal is 143.557. Next, water is added to the flask containing the metal and the mass is found to be 226.196. What is the density of the metal
Answer:
11.76 g/cm^3
Explanation:
Mass of empty flask and stopper = 64.232g
Mass of flask filled with water = 153.617 g
Mass of water = 153.617 g - 64.232g = 89.385 g
Mass of flask, stopper and metal = 143.557 g
Mass of metal = 143.557 g - 64.232g = 79.325 g
Mass of water, flask, stopper and metal = 226.196 g
Mass of water = 226.196 g - 143.557 g = 82.639 g
Since mass of water =volume of water
Volume occupied by metal = 89.385 cm^3 - 82.639 cm^3 = 6.746 cm^3
Density of metal = mass/volume = 79.325 g/6.746 cm^3
= 11.76 g/cm^3
A Single Orbital With Two Lobes At 90°In A Single Plane And A Node In The Center Would Likely Be Found Where?
a.4s
b.4p
c.4d
d. it would not be found in any of these
e.4f
Which of the following is most likely to happen when a sound wave reflects
off a hard surface? (Assume that neither the source of the sound nor the hard
surface is moving.)
A. A change in speed
B. An echo
C. A change in pitch
D. A beat frequency
В
an echo is caused by the fact that waves can be reflected by solid surfaces, this is due to the dynamic pattern of rarefactions and air seals near the reflecting surface
What particules make up the nucleus
Answer:
nucleus is a collection of particles called protons,which are positively charged..and neutrons which are electrically neutral..electrons which are negatively charged..and neutrons are in turn made up of particles called quarks ..
Explanation:
hope this helps u ...
Answer:
The Nucleus is made up of protons and neutrons.
please see attachment
Answer:
I'll see it
Explanation:
Decide which of the following statements are true and which are false.
True False: Real gas molecules behave most ideally at low temperature and high pressure.
True False: Ideal gas molecules have small volumes and exert weak attractive forces on one another.
True False: At constant temperature, the heavier the gas molecules, the smaller the average velocity.
True False: In order for two separate 1.0 L samples of O2(g) and H2(g) to have the same average velocity, the O2(g) sample must be at a lower temperature than the H
2(g) sample.
True False: At constant temperature, the heavier the gas molecules, the larger the average kinetic energy.
True False: As temperature decreases, the average kinetic energy of a sample of gas molecules decreases.
Answer:
False
True
True
False
False
True
Explanation:
Ideal behavior of gases is observed at high temperature and low pressure when the gas molecules are isolated from each other.
According to the kinetic theory of gases, gases occupy negligible volume and do not exert significant attractive forces on each other.
The average velocity of gases at constant temperature depends on molecular mass. Heavier molecules possess smaller average velocity than lighter molecules at constant temperature.
At constant temperature, molecules of different gases have the same average kinetic energy but different average velocities since they have different molecular masses. So, the average kinetic energy of gas molecules only depends on temperature.
describe briefly the laboratory preparation of methane gas
Answer:
In the laboratory, methane is formed by heating sodium ethanoate with a mixture of sodium hydroxide and calcium oxide, called soda lime, on heating in the presence of a catalyst, calcium oxide, the -COONa group from sodium ethanoate is replaced by the hydrogen atom from sodium hydroxide, forming methane and sodium
Explanation:
Consider the reaction: A(aq) + 2B (aq) === C (aq). Initially 1.00 mol A and 1.80 mol B
were placed in a 5.00-liter container. The mole of B at equilibrium was determined to
be 1.00 mol. Calculate K value.
0.060
5.1
25
17
Ugh
Answer:
17
Explanation:
Step 1: Calculate the needed concentrations
[A]i = 1.00 mol/5.00 L = 0.200 M
[B]i = 1.80 mol/5.00 L = 0.360 M
[B]e = 1.00 mol/5.00 L = 0.200 M
Step 2: Make an ICE chart
A(aq) + 2 B(aq) ⇄ C(aq)
I 0.200 0.360 0
C -x -2x +x
E 0.200-x 0.360-2x x
Then,
[B]e = 0.360-2x = 0.200
x = 0.0800
The concentrations at equilibrium are:
[A]e = 0.200-0.0800 = 0.120 M
[B]e = 0.200 M
[C]e = 0.0800 M
Step 3: Calculate the concentration equilibrium constant (K)
K = [C] / [A] × [B]²
K = 0.0800 / 0.120 × 0.200² = 16.6 ≈ 17
If a buffer is composed of 23.34 mL of 0.147 M acetic acid and 33.66 mL of 0.185 M sodium acetate, how many mL of 0.100 M NaOH can be added before the buffer capacity is reached
Answer:
25.5mL of 0.100M NaOH are needed to reach buffer capacity.
Explanation:
The buffer capacity is reached when the ratio between moles of conjugate base (Sodium acetate) and moles of weak acid (Acetic acid) is 10:
Moles sodium acetate / Moles Acetic acid = 10
The reaction of acetic acid, HA, with NaOH, to produce sodium acetate, NaA is:
HA + NaOH → H2O + NaA
That means the moles of NaOH added = Moles of HA that are being subtracted and moles of NaA that are been produced.
The initial moles of each species is:
Acetic acid:
23.34mL = 0.02334L * (0.147mol / L) = 0.00343 moles Acetic Acid
Sodium Acetate:
33.66mL = 0.03366L * (0.185mol / L) = 0.00623 moles Sodium Acetate
We can write the moles of each species when NaOH is added as:
Moles sodium acetate / Moles Acetic acid = 10
0.00623 moles + X / 0.00343 moles - X = 10
Where X are moles of NaOH added
Solving for X:
0.00623 moles + X = 0.0343 moles - 10X
11X = 0.0281
X = 0.00255 moles of NaOH are needed
In Liters:
0.0255mol NaOH * (1L / 0.100mol) = 0.0255L of 0.100M NaOH are needed =
25.5mL of 0.100M NaOH are needed to reach buffer capacity
draw all the possible isomers of octane
Answer:
helps
Explanation:
Calculate the heat change in calories for melting of 0.30 kg of water at 0*C. The
heat of fusion for water is 80 cal/g. The heat of vaporization of water is 540 cal/g.
The specific heat capacity of water is 1.00 cal/g*C.
Answer: 24 kcal
Explanation:
Given
Mass of water [tex]m=0.3\ kg[/tex]
Temperature of water [tex]T_1=0^{\circ}[/tex]
Heat of fusion [tex]L_f=80\ cal/g[/tex]
Heat of vaporization [tex]L_v=540\ cal/g[/tex]
Specific heat of water [tex]c=1\ cal/g.^{\circ}C[/tex]
Heat require to melt the ice is
[tex]\Rightarrow Q=mL_f\\\Rightarrow Q=0.3\times 1000\times 80\\\Rightarrow Q=24000\ cal\ or\ 24\ kcal[/tex]
Thus, 24 kcal of heat is required to melt 0.3 kg of ice.
