short story about The Blind Date by Jeffrey Archer
A sample of radioactive waste has a half-live of 40 years and an activity level of 4 curies. After how many years will the activity level of this sample be 0. 5 curies?
After 160 years, the activity level of the sample will be 0.5 curies.
What is half-life?Half life of any radioactive waste is the half decay of that product.
The formula is [tex]\dfrac{\lambda }{\lambda_1} = 2^\dfrac{a}{b}[/tex]
Where, λ is 4 cruies
λ1 is 0.5 cruies
b = 40 years
Putting the values in the equation
[tex]\dfrac{4}{0.5} = 2^\dfrac{a}{40}\\\\\\\dfrac{a}{40} = 4\\ = 160 years[/tex]
Thus, the correct option is 160 years.
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What volume of a 0.295 M nitric acid solution is required to neutralize 24.8 mL of a 0.107 M potassium hydroxide solution
Answer: 9.00 mL
Explanation:
[tex]M_{A}V_{A}=M_{B}V_{B}\\(0.295)V_{A}=(0.107)(24.8)\\V_{A}=\frac{(0.107)(24.8)}{(0.295)} \approx \boxed{9.00 \text{ mL}}[/tex]
In[7.60x10-³] = In(5.63×10-2) - (k s¯¹)(480 s)
Answer:
I'm not understand that question
I'm so sorry
6. Which of these are ways that humans are helping endangered animal populations? (Select all that apply.)
requiring a license to hunt
establishing protected preserves
captive breeding
laws to protect endangered species
The ways in which humans are helping endangered animal populations are as follows:
establishing protected preserveslaws to protect endangered speciesWhat are endangered species?Endangered species are species which are in danger of becoming extinct throughout all or a significant portion of its range.
Extinction refers to the non-existence of a particular species of an organism on the Earth.
One of the ways by which a species of animal can become endangered is through indiscriminate poaching, hence, the ways by which humans are helping endangered animal populations are as follows:
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Answer:
b and
Explanation:
Use the following equation to answer the following question
3 H2 + Na2 —-> 2 NH3
a) Determine the limiting reactant when 5.78 g of H2, and 6.28 g N2 are reacted to make NH3 you expect to get out of the chemical reaction.
Answer: nitrogen
Explanation:
Converting 5.78 g of hydrogen to moles, we know that the formula mass of hydrogen is about 2(1.00794)=2.01588 g/mol, so 5.78 grams is about 5.78/2.01588=2.867 mol.Converting 6.28 g of nitrogen to moles, we know that the formula mass of nitrogen is about 2(14.0067)=28.0134 g/mol, so 6.28 grams is about 6.28/28.0134 = 0.22417 mol.From the equation, we know that for every 3 moles of hydrogen consumed, 1 mole of nitrogen is consumed.
Considering the hydrogen, the reaction can occur 2.867/3=0.955 times.Considering the nitrogen, the reaction can occur 0.22417 times.Therefore, nitrogen is the limiting reactant.
What is the change in the freezing point of water when 35.0 g of sucrose is
dissolved in 300.0 g of water?
Kf of water = -1.86°C/mol
molar mass sucrose = 342.30 g/mol
ivalue of sugar = 1
A. -0.183°C
B. 0.0606 °C
C. 0.217°C
D. -0.634°C
From the calculations, we can see that, the change in the freezing point is -0.634°C.
What is freezing point?The term freezing point refers to the temperature at which a liquid is changed to solid.
Given that;
ΔT = K m i
Number of moles sucrose = 35.0 g/ 342.30 g/mol = 0.1 moles
molality = 0.1 moles/ 300.0 * 10^-3 Kg
= 0.33 m
Thus;
ΔT = -1.86°C/mol * 0.33 m * 1
= -0.634°C
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What kind of scientist would study how mistletoe harms trees
Answer:
A Dendrologist! They are the type of Scientist that studie trees.
Can someone help??. This is super hard
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Question 29 of 32
Why does a scientist form a hypothesis?
A. To prove a theory
B. To explain the data that are collected from an experiment
C. To explain his or her opinion about an observation
D. To provide a statement that can be tested with an experiment
A scientist form a hypothesis because he wants to : (D). To provide a statement that can be tested with an experiment
Meaning of hypothesisA hypothesis can be defined as a statement that is proposed by a scientist and needs to be tested by other scientist.
So in a simple statement, hypothesis in its raw state is an untested and unproven fact that is propagated by a scientist.
In conclusion, a scientist form a hypothesis because he wants to : To provide a statement that can be tested with an experiment
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What do esters aldehydes and ketones all have in common? (Look back at
table R and be specific!)
what is the wavelength of an electromagnetic wave that has a frequency of
1.82 x 1018 hz in a vacuum? (the speed of light in a vacuum is 3.00 x 108
m/s.)
The wavelength of an electromagnetic wave that has a frequency of 1.82 x 10¹⁸ Hz in a vacuum is 1.65 × [tex]10^{-10}[/tex]m.
How to calculate wavelength?The wavelength of a wave can be calculated by dividing the speed of the wave by its frequency.
According to this question, a wave has a frequency of 1.82 x 10¹⁸ Hz in a vacuum and speed of light in a vacuum is 3.00 × 10⁸ m/s.
λ = [tex]\frac{v}{f}[/tex]
Wavelength (λ) = 3 × 10⁸ ÷ 1.82 × 10¹⁸
Wavelength (λ) = 1.65 × [tex]10^{-10}[/tex] m
Therefore, the wavelength of an electromagnetic wave that has a frequency of 1.82 x 10¹⁸ Hz in a vacuum is 1.65 × [tex]10^{-10}[/tex]m.
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Question 2
1 p
White phosphorus ignites easily. This is an example of _____ property
- physical
- neither
- chemical
- both
Answer:
Chemical properties because if it was physical property then it will glow in dark
Based on table n, uranium-238 and uranium-235 have different
a)decay modes
b)half lives
c)number of protons
d)number of electrons
According to table N, the isotopes uranium-238 and uranium-235 have different half lives.
What are radioactive nuclides?Radioactive nuclides are those nuclides that are able to undergo radioactive decay. They have specific modes of decay that is peculiar to each isotope.
Hence, according to table N, the isotopes uranium-238 and uranium-235 have different half lives.
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Consider a 1.0-L sample of helium gas and a 1.0-L sample of argon gas, both at room temperature and atmospheric pressure. Do the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample
Yes, the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample.
What is Average Kinetic Energy ?The average kinetic energy of a gas molecule is defined as the product of half of the mass of each gas molecule and the square of the RMS speed.
The average kinetic energy equation is independent of Molar mass.
It's only a function of temperature.
So if they're at the same temperature they will have the same average kinetic energy.
Therefore, the atoms in the helium sample have the same average kinetic energy as the atoms in the argon sample
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Could someone explain this for me I don't understand?
Answer:
Ok so I assume they gave u a reaction before asking this question. Look at that reaction and try to figure out what substances are changing in valency, if there is a substance(s) that doesn't change its valency then it's a spectator ion.
Leslie incorrectly balances an equation as 2c4h10 12o2 → 8co2 10h2o. which coefficient should she change? 2 8 10 12
[tex]2C_4H_10+13O+2[/tex] → [tex]8CO_2+10H_2O[/tex] is the balanced chemical equation.
Hence, she should change the coefficient to 2, 13, 8, 10.
What is a balanced chemical equation?A balanced equation contains the same number of each type of atom on both the left and right sides of the reaction arrow.
[tex]2C_4H_10+13O+2[/tex] → [tex]8CO_2+10H_2O[/tex] is the balanced chemical equation.
Hence, she should change the coefficient to 2, 13, 8, 10.
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Answer:
Its d
Explanation:
i did the quiz
A woman is deciding between three alarm systems to install in her home. Each alarm system produces a wave with a different wavelength and decibel level, as shown in the following table.
If the woman wants the alarm with the lowest pitch, which alarm should she choose? Explain your answer.
Based on the data in the table, which alarm produces sound waves with the greatest amplitude? Explain your answer.
Write 3–4 sentences identifying which alarm has the lowest pitch and explain why you chose that alarm?
Write 3–4 sentences identifying the alarm that produces a sound with the greatest amplitude and explain why you chose that alarm?
Answer:
Based on the data in the table, which alarm produces sound waves with the greatest amplitude? Explain your answer.
this bit says based on the table but there is no table.
283.5 g of tin was heated from 25.6 to 107.5°C. How much energy was used to heat tin? (Specific heat capacity of Sn is 0.222 J/g x °C)
Answer: 5150 J
Explanation:
[tex]Q=mc \Delta T\\\\Q=(283.5)(0.222)(107.5-25.6)\\\\Q \approx \boxed{5150 \text{ J}}[/tex]
Scientists made the following two observations about emission spectra: each element has a unique emission spectrum. atoms emit energy only at specific wavelengths. describe how the bohr model explains both of these observations.
In this model, electrons are found on unique levels and when jumping from one level to another, electrons emit light at a specific wavelength.
What is the Bohr model?The Bohr model is an atomic model describing the properties of atoms and their constituents (electrons).
This model states different atoms have specific levels of energy where electrons can be located.
In conclusion, in this model, electrons are found on unique levels and when jumping from one level to another, electrons emit light at a specific wavelength.
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Answer:
In the Bohr model, electrons can exist only in certain energy levels surrounding the atom. The energy levels in each atom are unique. When electrons jump from a higher energy level to a lower one, they emit light at a wavelength that corresponds to the energy difference between the levels.
Explanation:
Ed22
which of the following with the kinetic theory address? a
A. Vibrations in molecules
B. Oxidation states of Adams
C. Shapes of molecules
D. Energy levels and electrons
Answer:A
Explanation:
The kinetic molecular theory of matter states that: Matter is made up of particles that are constantly moving. All particles have energy, but the energy varies depending on the temperature the sample of matter is in.This is turn determines shearer the substance exists in the solid, liquid, or gaseous state.
Match the following terms:
Answer:
See below ~
Explanation:
A to B
⇒ Solid Phase
==========================================================
B to C
⇒ Melting
==========================================================
C to D
⇒ Liquid Phase
==========================================================
D to E
⇒ Vaporizing
============================================================
E to F and beyond
⇒ Gas Phase
If the half-life of a radioactive group of atoms is 100 years, then how old is the rock if there have been two half-lives? show your work
The rock will be 200 years old if there have been two half-lives.
What is the half life ?The half-life of a radioactive isotope refers to its decay period, which is the average lifetime of an atom before it disintegrates.
In this question (t½) of rock is 100 years, which means that after 100 years half of the sample would have decayed and half would be left as it is.
after two half lives or 200 years , the rock will be 200 years old.
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(03.03 MC)
What best describes the bonding in a carbon dioxide molecule? (5 points)
- Carbon shares two of its electrons, and each oxygen shares four of its electrons.
- Carbon shares four of its electrons, and each oxygen shares two of its electrons.
- Carbon receives two electrons from each of the two oxygen atoms.
- Carbon transfers two electrons to each of the two oxygen atoms.
Answer:
- Carbon shares four of its electrons, and each oxygen shares two of its electrons.
Explanation:
Carbon needs 4 electrons to reach a full outer shell while oxygen needs 2 to reach a full outer shell.
Engineers are trying to improve a race car. Their goal is to increase the acceleration of the car using the same engine. Which change shows the best application of Newton’s laws of motion to achieve this goal?
increasing the inertia of the car
decreasing the reaction force
increasing the action force
decreasing the mass of the car
If the engineers are trying to increase the acceleration of the car, they have to decrease the mass of the car.
What is Newtons law?The Newtons laws of motion form the basis of the discussion about motion. We know that from the second law of Newton F = ma
Thus, if the engineers are trying to increase the acceleration of the car, they have to decrease the mass of the car.
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calculate the number of moles of nitrogen monoxide gas used to form 72.0 grams of water vapor.
4 moles of nitrogen monoxide gas used to form 72.0 grams of water vapor.
What is a mole ?A mole is the measurement unit which is used to correlate the molar mass with number of molecules present.
The equation for reaction of Nitrogen monoxide to form water vapor is given by
4NH₃ + 6NO ----> 5N₂ + 6H₂O
72 grams of water vapor means = 72/18 = 4 mole of water vapour
The mole fraction of NO to H₂O is 6 : 6
Therefore for 4 moles of water vapor formation , 4 moles of nitrogen monoxide will be required.
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Based on the activity series provided, which reactants will form products? f > cl > br > i cui2 br2 right arrow. cl2 alf3 right arrow. br2 nacl right arrow. cuf2 i2
The reactants that will form products will be [tex]2CuI_2 + Br2[/tex].
Activity seriesElements at higher positions in the activity series will be able to displace those in lower positions in solutions.
Thus:
[tex]2CuI_2 + Br2 --- > 2CuBr +2 I_2[/tex] because Br is higher than I in the activity series.
Cl cannot displace F in [tex]Cl2 + AlF_3[/tex] because F is higher than Cl in the activity series.
Also, Cl is higher than Br in the activity series, thus, the reaction [tex]Br_2 + NaCl[/tex] cannot form products.
I cannot displace F, thus, [tex]CuF_2 + I_2[/tex] cannot form products.
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Type the correct answer in the box. Use numerals instead of words.
A copper coin with a mass of 6.30 grams changes temperature in the sunshine from 20.0°C to 32.0°C. How much energy is transferred? The specific heat capacity of copper is 0.377 joules/gram degree Celsius. Express your answer to three significant figures.
The amount of energy transferred to the coin is ???
joules.
28.5 J is the amount of energy transferred to the coin.
What is specific heat capacity?The specific heat capacity is defined as the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature increases by 1 K (or 1 °C), and its units are J/(kg K) or J/(kg °C).
Energy is calculated mCΔT formula where,
m(mass)= 6.30 grams
C(specific heat capacity)= 0.377 j/g
ΔT(change in temperature)= 32.0°C- 20°C= 12 °C
Energy is, therefore:
Q = mCΔT
Q= 6.30 g x 0.377 j/g /°C x 12 °C
Q= 28.5 J
Hence, 28.5 J is the amount of energy transferred to the coin.
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Answer:
28.5 J is which what is the amount of energy transferred or given to the coin.
Explanation:
Have a great rest of your day
The one and only
Mr. Universe
For a given reaction, the activation energy is 63. 9 kj/mol. If the reaction rate constant is 4. 1 × 10–3 m–1s–1 at 32. 0ºc, what is the reaction rate constant at –5. 0 ºc? (r = 8. 314 j/k⋅mol)
The reaction rate constant at –5. 0 ºc is k2 is 24.3 KJ.
What is the activation energy?Activation energy is the minimum amount of energy required to carry out a reaction.
The formula is [tex]log \dfrac{k_2}{k_1} = \dfrac{Ea}{2.3R} \;( \dfrac{1}{T_1}- \dfrac{1}{T_2} )[/tex]
Given, K1 is [tex]4. 1 \times 10^3 m^-^1 s^-^1[/tex]
Temperature is 32
k2 is to find?
r = 8.314
Energy is 63.9
[tex]log \dfrac{k_2}{4. 1 \times 10^3 } = \dfrac{63.9 }{2.3\times 8.31} ( \dfrac{1}{32.0}- \dfrac{1}{-5.0} ) = 24.3 kj[/tex]
Thus, the correct option is k2 is 24.3 kJ
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Discuss, how equilibrium shifts in following reaction:
A) 2H2O2(aq) ⇄ 2H2O(l) + O2(s)
B) 3O2(g) ⇄ 2O3(g)?
Both reactions are the examples of reversible reaction and the reaction moves both forward and backward direction.
What happen in the reactions?In the first equation, hydrogen monoxide molecule is broken down into water and oxygen molecule. These two molecules again converted into hydrogen monoxide due to reversible reaction and gets equilibrium.
While on the other hand, in the second equation, oxygen molecule turns into ozone molecule and this ozone molecule again converted into oxygen molecule due to reversible reaction and attains equilibrium.
So we can conclude that both reactions are the examples of reversible reaction and the reaction moves both forward and backward direction.
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What is the name of cuo? explain how you determined the bond type and the steps you used to determine the naming convention for the compound.
The name of CuO is Copper(II) oxide have the two most common oxidation states of copper are +2 and +1.
What is copper oxide used for?Copper oxide is a trace element for the zootechnical and agricultural sector. Cupric oxide is also used as a raw material for the production of catalysts and pigments in the field of ceramics, glass and plastics.
This compound makes two different types of bonds being the hydrogen bond when it's a hydrogen and covalent bond when we have an oxygen or a nitrogen.
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