From the calculations, we can see that the half life of the material is 11.4 days
What is radioactivity?The term radioactivity refers to the spontaneous disintegration of a radioactive nucleus. The time taken for half of the radioactive material to remain.
Given that;
N/No = (1/2)^t/t1/2
N = amount that remained
No = amount that remained in the beginning
t = time taken
t1/2 = half life of the substance
N =Noe^-kt
4.995 ×10^9 = 1.75 x 10^12e^-55k
3.5* 10-2=e^-55k
k = ln3.5* 10-2/-55
k =0.06095
t1/2 = 0.693/0.06095
t1/2 = 11.4 days
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advantages of artificial silk over natural silk
Answer:
Less expensive than natural fibers
Strong and long-lasting
Easily available
Easy to maintain
Dry up quickly
To what temperature must a balloon, initially at 9°C and 4.00 L, be heated in order to have a volume of 6.00 L?
The balloon must be heated to a temperature of 150 °C in order to have a volume of 6.00 L.
How are volume and temperature of gases related?The volume of a gas is directly proportional to the temperature of the gas.
According to Charles' law: V1/T1 / = V2/T2
V1 =4.0 L
T1 = 9°C = (273. + 9) K = 282 K
V2 = 6.0 L
T2 = ?
T2 = V2×T1/V1
T2 = 6 × 282 / 4 = 423 K
423.2 K = 423 -273 = 150 °C
Therefore, the balloon must be heated to a temperature of 150 °C in order to have a volume of 6.00 L.
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1. When conducting this experiment, some procedures call for heating the substance several times and recording the mass after each heating, continuing until the mass values are constant. Explain the purpose of this process and how it might reduce errors.
The purpose of this process is to reduce the risk of having outliers of false results.
What is a good scientific experiment?It is important to bear in mind that a good scientific experiment usually tests one independent variable at a time, and that is why it is important to keep all other potential variables constant and to use a control group.
Although, the experiment you are referring to in your question is missing the general principle when conducting an experiment is the running of multiple tests before coming up with an actual test result.
Therefore, when completing a science experiment it is important to run multiple tests like heating the substance several times until a constant mass value is obtained, in other to ascertain the results. the reason why such process is undertaken is to reduce the risk of having outliers of false results.
A scientific experiment involves several procedures and this depends on the type and purpose of the experiment.
for example ;
An experiment with the purpose of determining how the mass of an object reacts to heat will require the mass of the object to be recorded after heating the object/substance several times.
Hence we can conclude that the purpose of the process is to reduce the risk of having outliers of false results.
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How can noble gas electron configuration be achieved?
Answer:
A noble gas configuration of an atom consists of the elemental symbol of the last noble gas prior to that atom, followed by the configuration of the remaining electrons. So for sodium we make the substitution of (Ne) for the 1s22s22p6 part of the configuration. Sodium's noble gas configuration becomes (Ne) 3s1.
Which statement below is true about a nuclear power plant?
O There is no air pollution from its operation.
O It produces less electricity than a coal-burning power plant.
O No fuel is needed for this type of power plant.
O It is not possible for a leakage of nuclear material.
Answer:
There is no air pollution
Explanation:
Unless there is a meltdown.
Nuclear plants generate far more power than coal plants
FUEL is needed....nuclear fuel
Leakage CAN happen.... see info on Three Mile Island or Cchernobryl (Ukraine)
If you add 25 g of CaCl2 to 1000. mL of water, what would the concentration of the solution be in grams/liter?
If you add 25 g of CaCl2 to 1000. mL of water, what concentration of the solution would be 0. 225 grams/liter
What is molarity?
Molarity or molar concentration(M) is defined as the amount of a substance in a given volume of solution.
It is also known as the moles of a solute in a liter of the solution.
How to determine the concentrationFormula:
Concentration or molarity = number of moles ÷ volume
The number of moles is derived thus;
Number of moles = mass ÷ molar mass
mass of CaCl2 = 25g and molar mass = 110. 98 g/mol
Number of moles = 25 ÷ 110. 98 = 0. 225 mol
Given the volume = 1000 ml = 1 liter
Concentration = 0.225 ÷ 1 = 0. 225 grams/liter
Therefore, If you add 25 g of CaCl2 to 1000. mL of water, the concentration of the solution would be 0. 225 grams/liter
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Suppose that 0.25M IBr in a flask is allowed to reach equilibrium at 150oC. The equilibrium concentration of Br2 is 0.013 M. Determine the Kc at this temperature. 2IBr(g) ←→ I₂(g) + Br₂(g)
Suppose that 0.25M IBr in a flask, the Kc at the given temperature is mathematically given as
Kc=0.00336814413
What is the Kc at the given temperature?Generally, the equation for Chemical Reaction is mathematically given as
2IBr--->T2+8r_2
Therefore
K={I2*Br2}/IBR^2
K=x^2/(0.25-2x)^2
Kc=0.13M^2/0.224M^2
Kc=0.00336814413
In conclusion, the Kc at the given temperature
Kc=0.00336814413
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b. The sedative Demerol hydrochloride has the formula
C15H22CINO2. How many grams are in 0.025 mole of
Demerol hydrochloride?
Dinitrogen oxide (or nitrous oxide), N₂O, also known as
laughing gas, is widely used as an anesthetic in dentistry.
The number of grams present in 0.025 mole of Demerol hydrochloride is 7.094 grams.
What is Demerol hydrochloride?It is a drug used in treating severe or moderate pain.
The moles are given = 0.025
The formula is C₁₅H₂₂CINO₂
The elements that present are C, H, Cl, N, O.
The molecular weight are given:
Carbon: 12.0107
Hydrogen: 1.00784
Chlorine: 35.453
Nitrogen: 14.007
Oxygen: 15.999
Multiply the molecular weight with moles and add them
(15 x 12.0107) + (22 x 1.00784) + (1 x 35.453) + (1 x 14.007) + (2 x 15.999) = 283.79098 grams per mole.
Now, multiply the number of moles given with the total molecular weight
283.79098 x 0.025 = 7.094
Thus, the number of grams are 7.094.
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HELPP!!
Methane (CH4) undergoes combustion. Which products form?
A. CO₂ and H₂
B. C and H₂O
C. CO₂ and H₂O
D. CO₂, H₂O, and 02
Answer: C. CO₂ and H₂O
Explanation:
Combustion reactions produce carbon dioxide and water.
Convert 7.50 mol of Li₂O to grams
Answer:
224.1105 grams is the answer
What’s properties my change during a chemical reaction
Answer:
The signs of chemical change include changes in color, temperature, the production of light, changes in odor, and the formation of gases.
Two identical syringes are filled to the same volume at the same temperature and pressure. If one
syringe is filled with chlorine gas and the other with nitrogen gas
A. the syringe filled with nitrogen gas contains more moles of gas.
B. the syringe filled with nitrogen gas contains more grams of gas.
C. the different gases have the same average kinetic energy.
D. the molecules of chlorine gas have a higher average velocity than the molecules of nitrogen gas.
Could someone explain why the answer is C?
The temperature is the same, so the amount of kinetic energy will also be the same.
What is the number of molecules in CaCo3
Answer:
Solution — Molar mass (Molecular mass in gram) of CaCO3 = 40+12+3×16 = 100 g No. of moles of CaCO3 = No. of molecules/Avogadro constant = 6.022 × 1023/ 6.022 × 1023 = 1 mole Mass of CaCO3 = No. of moles × molar mass = 1 × 100 g = 100 g.
Explanation:
The decay of a living things allows chemical elements to be lost.
Answer: is is true
Explanation:
How many moles of aluminum oxide (Al2O3) are produced by reacting 5 moles of iron oxide (FeO)?
2AI+ 3FeO --> 3Fe + 1Al₂O3
Answer:
1.67 moles Al₂O₃
Explanation:
To find the amount of aluminum oxide produced, you need to start with 5 moles FeO and multiply it by the mole-to-mole ratio displaying the relationship between moles FeO and moles Al₂O₃. This ratio incorporates the coefficients from the equation. Remember, make sure to write the ratio in a way that allows for the cancellation of moles FeO.
2 Al + 3 FeO ---> 3 Fe + 1 Al₂O₃
5 moles FeO 1 mole Al₂O₃
-------------------- x ---------------------- = 1.67 moles Al₂O₃
3 moles FeO
A dunk tank hold 30,533 moles of water? How many grams of water are in the tank?
The mass of water in the tank, given the data from the question is 549594 g
Description of moleThe mole of a substance is related to it's mass and molar mass according to the following equation:
Mole = mass / molar mass
How to determine the mass of water in the tankFrom the question given above, the following data were obtained:
Mole of water = 30533 molesMolar mass of water = 18 g/mol Mass of water = ?The mass of the water can be obtained as follow:
Mass = mole × molar mass
Mass of water = 30533 × 18
Mass of water = 549594 g
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Which of the following is ture about a scientific hypothesis?
N2O4(g) + 4H2(g) → N2(g) + 4H2O(g), solve using standard enthalpies of formation
The standard enthalpy of formation (Δ[tex]H_f[/tex]) is a measure of the energy released or consumed when one mole of a substance is created under standard conditions from its pure elements.
Standard enthalpies (Δ[tex]H_f[/tex]) of formation for given reaction is 978.3 kJ
What is Standard enthalpies of formation?The standard enthalpy of formation is defined as the enthalpy change when one mole of a substance in the standard state (1 atm of pressure and 298.15 K) is formed from its pure elements under the same conditions.
Given reaction ;
[tex]N_2O_4(g) + 4H_2 (g) - > N_2(g) + 4H_2O(g)[/tex]
To Find : Δ[tex]H_f[/tex]
Δ[tex]H_f[/tex] = ∑np Δ[tex]H_f[/tex] (products) – ∑np Δ[tex]H_f[/tex] (reactants)
Δ[tex]H_f[/tex] = [1(Δ[tex]H_f[/tex] [tex]N_2[/tex]) + 4(Δ[tex]H_f[/tex] [tex]H_2O[/tex])] – [1(Δ[tex]H_f[/tex] [tex]N_2O_4[/tex]) + 4(Δ[tex]H_f[/tex] [tex]H_2[/tex])]
Δ[tex]H_f[/tex] = [1(0) + 4(-241.8)] – [1(+9.16) + 4(0)]
Δ[tex]H_f[/tex] = [4(-241.8)] – [1(+9.16)] = 978.3 kJ
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URGENT HELP NEEDED!!! SPACE
Record your observation statements from Space Academy.
When the mass of the sun is larger, Earth moves around the sun at a faster (faster, slower) pace.
When the mass of the sun is smaller, Earth moves around the sun at a slower (faster, slower) pace.
When Earth is closer to the sun, its orbit becomes faster (faster, slower).
When Earth is farther from the sun, its orbit becomes slower (faster, slower).
For each trial, record the orbit number of each planet from the sun. Be sure to indicate the number of planets in the habitable zone after each trial. Create a different configuration of planets for each trial. An example has been supplied for you.
Orbit Number
Planet One Orbit Number
Planet Two Orbit Number
Planet Three Orbit Number
Planet Four Number of planets in the habitable zone Number of planets left in successful orbit
Example: sun's mass 1x
1
3
5
6
1
2
sun's mass 1x—Trial One
1
5
2
3
1
1
sun's mass 1x—Trial Two
1
2
0
0
2
2
sun's mass 2x—Trial One
1
0
0
0
1
0
sun's mass 2x—Trial Two
1
3
2
0
4
0
sun's mass 3x—Trial One
1
2
0
0
2
0
sun's mass 3x—Trial Two
1
0
0
0
1
3
Conclusion:
Your conclusion will include a summary of the lab results and an interpretation of the results. Please answer all questions in complete sentences using your own words.
Using two to three sentences, summarize what you investigated and observed in this lab.
You completed three terra forming trials. Describe the how the sun's mass affects planets in a solar system. Use data you recorded to support your conclusions.
In this simulation, the masses of the planets were all the same. Do you think if the masses of the planets were different, it would affect the results? Why or why not?
How does this simulation demonstrate the law of universal gravitation?
It is the year 2085, and the world population has grown at an alarming rate. As a space explorer, you have been sent on a terraforming mission into space. Your mission to search for a habitable planet for humans to colonize in addition to planet Earth. You found a planet you believe would be habitable, and now need to report back your findings. Describe the new planet, and why it would be perfect for maintaining human life.
The new planet is suitable for human life because it is similar to planet earth.
Describe the new planet, and why it would be perfect for maintaining human life?
The new planet has similar atmosphere just like the earth's atmosphere. It has large amount of vegetation that can hold large amount of animals. It is suitable for growing for different crops that provide food to humans.
So we can conclude that the new planet is suitable for human life because it is similar to planet earth.
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What is the Substance that is oxidized in 2K+ S > K2S
Answer :]
This is an oxidation-reduction (redox) reaction:
S0 + 2 e- → S-II (reduction)
2 K0 - 2 e- → 2 KI (oxidation)
S is an oxidizing agent, K is a reducing agent.
Answer:
K
Explanation:
Here, in this reaction 2 moles of potassium react with 1 mole of sulfur to form 1 mole of potassium sulfide.
Let's compare the electronic configurations of both elements :
⇒ K = {2, 8, 8, 1}
⇒ K can attain noble gas configuration by losing one electron
⇒ K exists as : K⁺
⇒ S = {2, 8, 6}
⇒ S can attain noble gas configuration by the addition of 2 electrons
⇒ S exists as S²⁻
Now, we know that will lose protons when oxidized. Hence, here the substance which is oxidized is K
What is the product of the unbalanced equation below?
H₂(g) + Cl₂(g) →
The Periodic Table
OA. H₂(g) + Cl₂(g)
OB. H₂Cl₂(9)
O C. HC1₂(g)
OD. HCI(g)
D
Explanation:
B/c both the hydrogen and chlorine have the same valance number so if a metal or non metal have the same valance number you should cancel out the numbers and you will have to put only the non metal or metals.
How many moles of au are in 66.4g of au
Answer:
0.3371 moles
Explanation:
gold is 196.967 grams per mole
66.4 grams divided by 196.967 grams per mole =
0.3371 moles
A lead ball is added to a graduated cylinder containing 50.6 ml of water, causing the level of the water to increase to 93.0 mL. What is the volume in milliliters of the lead ball, Vieras? Viead =
42.4 ml is the volume in milliliters of the lead ball if a lead ball is added to a graduated cylinder containing 50.6 ml of water.
What is a graduated cylinder?A tall narrow container with a volume scale is used especially for measuring liquids.
The graduated cylinder contains water
mL is a volume unit.
Water volume = 50.6 ml
The lead ball caused an increase in volume from 50.6 ml to 93.0 mL.
The new volume is the lead ball volume plus the original water volume :
Final volume = Vlead ball+ Water original volume
[tex]93.0 mL= V_(lead ball) +50.6 ml[/tex]
[tex]V_(lead ball) = 93.0 mL - 50.6 ml[/tex]
[tex]V_(lead ball) = 42.4 ml[/tex]
Hence, 42.4 ml is the volume in milliliters of the lead ball.
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Complete the balanced neutralization equation for the reaction below:
HNO3(aq) + Ba(OH)2(aq) →
The complete equation will look thus: [tex]2HNO_3(aq) + Ba(OH)_2(aq) --- > Ba(NO_3)_2 + 2H_2O[/tex]
Balancing equationsIn order for equations to be balanced, the component atoms in the reactants and products must be the same in terms of number.
Thus, in the given equation, the number of H, N, O, and Ba atoms in the reactants and the products must be equal.
Therefore, the overall equation becomes:
[tex]2HNO_3(aq) + Ba(OH)_2(aq) --- > Ba(NO_3)_2 + 2H_2O[/tex]More on balancing equations must be found here: https://brainly.com/question/12192253
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Answer:2HNO3 + Ba(OH)2 → Ba(NO3)2 + 2H2O
Explanation:
HNO3 + Ba(OH)2 = Ba(NO3)2 + H2O
This is what each element is....
H= 1+2=3 H=2
N=1 N=2
O=2+2=4 O=4+1=5
Ba=1 Ba=1
Now to balance each side.....
H=2+2=4 H=2++2=4
N=2 N=2
O=4+2=6 O=4+2=6
Ba=1 Ba=1
The balanced equation is now
2HNO3 + Ba(OH)2 → Ba(NO3)2 + 2H2O
The vapor pressure of benzene at 25°C is 95.1 mm Hg and of toluene 28.4 mm Hg. The mass fractions of benzene and toluene in a solution are 0.5.
a) Calculate the partial pressure of benzene and toluene above the solution.
b) Calculate the total vapor pressure above the solution.
c) Calculate the vapor composition above the solution.
Answer:
df dffdffdfd dffd ff d
Explanation:
df fd df f df df dfdf f fdf df df df fd
The magnet below is cut in half. What will be the result
the cut pieces will have their own north and south pole
The enzyme provided is a stock solution which should be diluted 50-fold with 0.001M HCl immediately before use.
Enzyme :1mg/ml chymotrypsin A in 0.001M HCl
How do I work out this calculation, if I want the 5ml of the diluted enzyme?
In order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.
What is dilution?Dilution is a process whereby a solution of lower concentration is prepared from one of a higher concentration.
Dilution is done by using the dilution formula below:
C1V1 = C2V2C1; Initial concentration of enzyme = 1 mg/mL
C2; Final concentration of enzyme = 1/50 mg/ml = 0.02 mg/ml
V1; Initial volume of enzyme = y
V2; Final volume = 5.0 ml
V1 = C2V2/C1
V1 = 0.02 * 5/1 = 0.1 mL
Therefore, in order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.
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How many grams of carbon monoxide must be placed into a 40.0 l tank to develop a pressure of 965 mm hg at 23 C?
The mass of carbon monoxide, CO that must be placed in the 40 L tank is 58.52 g
How to determine the mole of COVolume (V) = 16.8 L Pressure (P) = STP = 965 mmHg = 965 / 760 = 1.27 atmTemperature (T) = 23 °C = 23 + 273 = 296 KGas constant (R) = 0.0821 atm.L/Kmol Number of mole (n) =?n = PV / RT
n = (1.27 × 40) / (0.0821 × 296)
n = 2.09 moles
How to determine the mass of COMolar mass of CO = 28 g/moleMole of CO = 2.09 molesMass of CO = ?Mass = mole × molar mass
Mass of CO = 2.09 × 28
Mass of CO = 58.52 g
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what is the shape of the molecule that has 2 atoms bonded to a central atom and 1 lone pair of electrons
When there are two bond pairs and one lone pair, the molecule will have a bent molecular shape.
What is the shape of a molecule?The shape of a molecule depends on the orientation and number of electron pairs on the valence shell of the central atom in the molecule. This is based on the postulates of the valence shell electron pair repulsion theory.
When there are two bond pairs and one lone pair, the molecule will have a bent molecular shape.
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Is salmon fortified or enriched?