2. If the half-life of Francium-233 is 22 minutes, how much time must elapse in order for 60 grams of a 64 gram
sample to undergo decay? In other words, after how many minutes will you only have 4 grams of the original isotope
remaining?
Answer:
88 minutes
Explanation:
64 g ---> 32g ---> 16g ---> 8 g ---> 4 g
So in total, we have 4 half lives to reach 4.0 g
therefore, 4 x 22 minutes = 88 minutes
88 minutes or four half lives are required to have 4 grams of the original isotope remaining.
What is half life?Half -life of a substance is defined as the time which is required for half of the quantity of a radioactive substance to get decayed.It is a term which is used in nuclear chemistry for describing how quickly unstable atoms undergo radioactive decay into other nuclear species by emitting particles or the time which is required for number of disintegrations per second of radioactive material to decrease by one half of its initial value.
During first half life= 64 g of isotope is present , during second half life 1/2×64=32 g of isotope is present, during third half life 1/2×32=16 g of isotope is present.during fourth half life 1/2×16=8 g of isotope is present.
As 1 half life is 22 minutes 4 half lives=4×22=88 minutes.
Thus, 88 minutes are requires for 4 g of sample to remain.
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7. Which structural formula correctly represents a hydrocarbon molecule?
Answer:
the 4th one is the corrent one
51.86% of all the isotopes of an element have a mass of 106.82 amu and 48.14% have a mass of 109.03 amu.
What is the average mass of this element?
Answer:
Average Mass = 107.88 amu
Explanation:
We can calculate the average mass of an element by mutlpying the mass of its isotopes by their respective relative abundance and then making a total sum. Meaning that for this case:
Average Mass = 106.82 amu * 51.86/100 + 109.03 amu * 48.14/100Average Mass = 107.88 amuif 26.8g of copper (ll) chloride are dissolved in sufficient water to make 4.00 L of solution, what is the molarity of the solution? & what is the solvent?
Answer: Molarity of the solution is [tex]4.97 \times 10^{-2} M[/tex] and water is the solvent.
Explanation:
Given: Mass of solute = 26.8 g
Volume = 4.00 L
Now, moles of copper (II) chloride (molar mass = 134.45 g/mol) are calculated as follows.
[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{26.8 g}{134.45 g/mol}\\= 0.199 mol[/tex]
Molarity is the number of moles of a substance divided by volume of solution in liter.
Therefore, molarity of given solution is calculated as follows.
[tex]Molarity = \frac{no. of moles}{Volume (in L)}\\= \frac{0.199 mol}{4.00 L}\\= 0.04975 M\\= 4.97 \times 10^{-2} M[/tex]
Solvent is defined as a component which is present in higher amount in a solution. Generally, a solvent is present in liquid state but it can also be a solid or gas.
In the given solution, copper (II) chloride is dissolved in water so copper (II) chloride is the solute and water is the solvent.
Thus, we can conclude that molarity of the solution is [tex]4.97 \times 10^{-2} M[/tex] and water is the solvent.
What is the difference between strong and weak acids
Answer:
Weak acids don't fully dissociate in the solvent, whereas strong acid do.
Explanation:
Answer: Strong acids dissociate fully in water to produce the maximum number of H + ions. ... Weak acids, such as ethanoic acid (CH 3COOH), do not fully dissociate
Explanation:
Los ácidos fuertes se disocian completamente en agua para producir el máximo número de iones H +. ... Los ácidos débiles, como el ácido etanoico (CH 3COOH), no se disocian completamente
3. Heating the copper product at too high a temperature in an oxygen atmosphere results in the formation of copper( )oxde, . Write the balanced equation for this reaction.
which is the country to use paper currency
Answer:
the first country that uses paper currency is china
the first use of paper currency can be traced back to the year 806 AD in China where they were used as flying currency
More efficient plumbing reduces water pollution by _______. a. using more water b. using less water c. using cleaner water d. using dirty water Please select the best answer from the choices provided
Answer:
b. using less water
Explanation:
Pollution can be defined as the physical degradation or contamination of the environment through an emission of harmful, poisonous and toxic chemical substances.
In the United States of America, the agency which was established by US Congress and saddled with the responsibility of overseeing all aspects of pollution, environmental clean up, pesticide use, contamination, and hazardous waste spills is the Environmental Protection Agency (EPA). Also, EPA research solutions, policy development, and enforcement of regulations through the resource Conservation and Recovery Act.
In homes and offices, an effective and efficient design of pipes and other water-related facilities would go a long way to reduce water pollution because the water used are well managed and properly disposed into sinkholes.
Hence, more efficient plumbing reduces water pollution by using less water
Answer:
B
Explanation:
Explain ocean floor spreading and how this process is related to the mid-ocean ridge
Answer:
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.
Explanation:
Mid-ocean ridges and seafloor spreading can also influence sea levels. As oceanic crust moves away from the shallow mid-ocean ridges, it cools and sinks as it becomes more dense. ... Seafloor spreading proves that the ocean itself is a site of tectonic activity.
When a solute is added to water, the boiling point
Answer:
Boiling-point elevation describes the phenomenon that the boiling point of a liquid (a solvent) will be higher when another compound is added, meaning that a solution has a higher boiling point than a pure solvent. This happens whenever a non-volatile solute, such as a salt, is added to a pure solvent, such as water.
a mieral is ______
a. man-made
b. alive
c. non-living
d. a plant
Answer:
C
Explanation:
A mineral is a composition of different rocks, therefore it is not alive and non livine. It is also not man made, but natural
Why do electrons become delocalised in metals?
Answer:
All of the 3s orbitals on all of the atoms overlap to give a vast number of molecular orbitals which extend over the whole piece of metal. The electrons can move freely within these molecular orbitals, and so each electron becomes detached from its parent atom. The electrons are said to be delocalized.
Explanation:
I hope you understand
_H2+O2=_H2O
balance help please
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How does a new DNA molecule ensure that it has the same nucleotide sequence as the original DNA?
Answer:
This strand contains nucleotides that are complementary to those in the template sequence. Base pairing ensures that the sequence of nucleotides in the existing template strand is exactly matched to a complementary sequence in the new strand, also known as the anti-sequence of the template strand
For the combustion of acetaldehyde, CH2CHO, there is 42L at STP and 79g of Oz. How much water is produced?
Calculate the molarity when 3.55 moles of NaCl are dissolved to make 0.200 L of solution
Answer: The molarity of given solution is 17.75 M.
Explanation:
Given: Moles = 3.55 mol
Volume of solution = 0.2 L
Molarity is the number of moles of a solute present in liter of solution.
Hence, molarity of the given solution is calculated as follows.
[tex]Molarity = \frac{no. of moles}{Volume (in L)}\\= \frac{3.55 mol}{0.2 L}\\= 17.75 M[/tex]
Thus, we can conclude that the molarity of given solution is 17.75 M.
If a blender is plugged into a 128 V outlet that supplies 7.9 A of current, what amount
of power is used by the blender?
Power (P) = Current (1) times Voltage (V)
P = (0) (V)
P=?
1 =7.9A
V=128V
100 W
01011.2 w
267 W
Answer:
Power = 1011.2 Watts
Explanation:
Given the following data;
Voltage = 128 Volts
Current = 7.9 Amperes
To find the power rating;
Mathematically, the power rating of an electrical device is given by the formula;
Power = current * voltage
Power = 128 * 7.9
Power = 1011.2 Watts
18.2L of gas at 95°C and 760 torr is placed in a 15L container at 80 degrees * C ; what is the new pressure ?
Answer:
884.56 torr
Explanation:
Formula: [tex]\frac{P_{1}V_{1} }{T_{1}} = \frac{P_{2}V_{2} }{T_{2}}[/tex]
P = Pressure
V = Volume
T = Temperature in kelvin (Celsius + 273.15)
[tex]\frac{(760)(18.2) }{368.15} = \frac{P(15) }{353.15}[/tex]
[tex]P = \frac{(760)(18.2)(353.15) }{(368.15)(15)}[/tex]
P = 884.56169
What nuclear reaction could hydrogen undergo, fission or fusion?*
Answer:
Hydrogen (H) “burning” initiates the fusion energy source of stars and leads to the formation of helium (He).
FUSION Reaction
Explanation:
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Name the following compound
CH 3 – CH 2 – CH = CH – CH 2 – CH 3
Answer:
hex-3-ene
remember the least number rule and since the double bond lies at 3rd C-atom from either ways, the compound is named hex (six carbon atoms) -3(position of double bond)-ene (primary suffix for unsaturated organic compound where any two carbons have double bond). hex-3-ene.
if you have any doubt, please feel free to ask :-))
Which of these phrases accurately describe disproportionation? Check all that apply.
A single compound reacts with itself.
A single compound oxidizes and reduces a second compound.
A single compound is simultaneously oxidized and reduced.
A single compound is produced by the reaction of two ions.
A single compound acts as both the oxidizing agent and the reducing agent.
ANSWER: A,C,E on E2020
Answer:
A single compound is simultaneously oxidized and reduced.
Explanation:
In chemistry, disproportionation is a simultaneous oxidation and reduction of a single chemical specie.
What this means is that; in a disproportionation reaction, only one compound is both oxidized and reduced. This implies that two products are formed during disproportionation. One is the oxidized product while the other is the reduced product.
Consider the disproportionation of CuCl shown below;
2CuCl -----> CuCl2 + Cu
Here, CuCl2 is the oxidized product while Cu is the reduced product.
Answer:
A & c & e
Explanation:
Zoe is frying eggs in a pan. The eggs cook because of _____ of heat. Zoe feels hot as she stands near the stove mostly because of _____ of heat.
Answer:
1) conduction
2) Radiation
Explanation:
Conduction is a mode of heat transfer by which heat energy is transferred through a material, the average position of the particles of the material remaining the same.
Radiation is a process of heat transfer by which heat is transferred from a hotter to a cooler point without any intervening medium.
The pan used to fry the egg is a conductor of heat hence heat can pass through it by conduction thereby enabling the eggs to cook.
Heat can travel without an intervening medium hence Zoe feels hot near the stove. This ability of the heat to travel without an intervening medium is called radiation.
Answer:
Conduction first then radiation.
Explanation:
Convert from °C to K. 13°C
Answer:
286.15 Kelvin
Explanation:
Answer:
286.15
Explanation:
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Answer:
Deserts and oceans appear to be far from one another will little in common, but in fact, they're connected in an intresting way.Water from the open evaporates into clouds that travel and eventually empty the water onto the land,creating much-needed sources of water in dessert areas.Meanwhile,winds from the dessert sweep up billions of tons of dust intosky,at least a quarter of which falls into the ocean and provides nutrients for marine life.
Explanation:
Is sulfur pentoxide a ionic or covalent bond?
Why Uranium consider as non-renewable resource? Please I need it now and short answer with simple meaning!!
Rate in its natural state uranium -235 is a non renewable energy. although small quantities go a long way .For example the fission of one pound of uranium release more energy than burning three million pounds of coal.Nuclear fission reacts splits atoms to release the enriched uranium.
How many formula units (particles of AgNO3) are in 5.50
grams of AgNO3?
a 1.93 x 1022 molecules
b 8.67 x 1021 molecules
C 0.032 molecules
d 6.14 1022 molecules
e, 3.22 x 1022 molecules
Answer:
2.0 X 10²² molecules of AgNO₃Explanation:
Given 5.50 grams of AgNO₃, how many formula units of AgNO₃ are contained in the 5.50 grams of AgNO₃? (formula wt. of AgNO₃ = 169,87 g/mole).
Solution:
1st convert grams to moles => moles AgNO₃ = 5.50 g AgNO₃ / 169.841g AgNO₃ = 0.032377 mole AgNO₃ 2nd calculate number of particles in 0.032377 mole AgNO₃ . Number AgNO₃ molecules in 0.032377 mole AgNO₃ = 0.032377 mole AgNO₃ X 6.023 x 10²³ molecules of AgNO₃ /1.0 mole AgNO₃ = 1.95007 X 10²² molecules of AgNO₃ in 5.50 grams of AgNO₃. The appropriate form of the answer should contain 2 Sig,Figs. based on the data point having the least number of sig.figs. in the given data. This then is 5.50 grams of AgNO₃ which has 2 sig.figs. Therefore, the number of AgNO₃ molecules in 5.5 grams of AgNO₃ = 2.0 X 10²² molecules of AgNO₃. (Note: 1.95 rounds to 2.0).The number of molecules of silver nitrate in 5.5 grams has been [tex]1.93\;\times\;10^2^2[/tex]. Thus, option A is correct.
The formula unit has been given as the number of molecules of the compound. The number of molecules in a mole of compound has been given by the Avogadro law.
According to the Avogadro law, the number of molecules in a mole of sample has been equivalent to the Avogadro number, i.e. [tex]6.023\;\times\;10^2^3[/tex].
Computation for formula unit of Silver nitrateThe given mass of silver nitrate has been 5.50 grams.
The molar mass of silver nitrate has been 169.84 g/mol.
The moles of silver nitrate has been:
[tex]\rm Moles=\dfrac{Mass}{Molar\;mass} \\\\
Moles=\dfrac{5.5}{169.84}\;mol\\\\
Moles=0.032\;mol[/tex]
The moles of silver nitrate in the sample has been 0.032 mol.
The number of molecules of silver nitrate has been:
[tex]\rm 1\;mole=6.023\;\times\;10^2^3\;molecules\\ 0.032\;mol=0.032\;\times\;6.023\;\times\;10^2^3\;molecules\\ 0.032\;mol=1.93\;\times\;10^2^2\;molecules[/tex]
The number of molecules of silver nitrate in 5.5 grams has been [tex]1.93\;\times\;10^2^2[/tex]. Thus, option A is correct.
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Answer:
the property of air shown in the figure describe A.mass
You removed a Coke can from the refrigerator. When you come back a few minutes later, you realize the can has begun to "sweat".
In other words, moisture forms on the outside of the can. Select ALL of the statements that describe the formation of condensation
on the can.
)
A)
Water vapor in the air gains energy, causing it to form condensation on the
can
B)
As water molecules in the air come in contact with the cold can, they will
slow down.
C)
As water molecules in the warm air collide with the cold can, they will lose
energy and become colder.
D)
Vapor molecules in the air are attracted to water molecules on the can
causing them to bind to the can.
E)
Condensation on the can comes from water vapor in the air cooling and
slowing and becoming liquid on the outside of the can
Answer:
B
Explanation:
The statements that describe the formation of condensation on the can are
B) As water molecules in the air come in contact with the cold can, they will slow down.
C) As water molecules in the warm air collide with the cold can, they will lose energy and become colder.
E) Condensation on the can comes from water vapor in the air cooling and slowing and becoming liquid on the outside of the can.
What is condensation?Condensation is the process of converting water vapor into liquid. The process happens when the temperature lowers and the vapor in the air condenses and converts into water molecules.
Here, the condensation occurs near the cold can, the surrounding air condenses, lowered the energy and converts it into water molecules.
Thus, the correct options are B, C, and E.
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How many total atoms are there in C6H12O6 + 6O2?
Explanation:
C - 6 atoms
H - 12 atoms
O - 6 atoms + 12 atoms
total number of stoms = 6 + 12 + 6 + 12 = 36