Answer: The original mass of the sample of Uranium-235 is 0.7308 mg
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for calculating rate constant
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{7.0\times 10^8years}=0.099\times 10^{-8}years^{-1}[/tex]
b) for time of [tex]2.8\times 10^9[/tex] years
[tex]2.8\times 10^9=\frac{2.303}{0.099\times 10^{-8}}\log\frac{a}{0.04625}[/tex]
[tex]\log\frac{a}{0.04625}=1.2[/tex]
[tex]\frac{a}{0.04625}=15.8[/tex]
[tex]a=0.7308mg[/tex]
The original mass of the sample of Uranium-235 is 0.7308 mg
Which of the following is best described by the term macroscopic?
A. H₂O
B. Water is composed of two hydrogen atoms and one oxygen atom.
C. Water in the liquid phase boils to become a gas.
D. Water molecules in the solid phase are tightly held together.
Answer:
D
Explanation:
because macroscopic is visible to the naked eye.
The atomic mass of boron is 10.811. What is the mass number of the most
abundant isotope of boron?
A.9
B.12
C.11
D.10
Answer:
C.11
Explanation:
Boron-11 makes up around 80% of all natural Boron. And, typically, the quickest way to determine the most abundant isotope of an element is to just round the atomic mass to the nearest whole number.
Use the balanced "ham sandwich" equation from the concept,
repeated below.
2H + C +T+5P+ 2B + H2CTP, B2
How many slices of cheese are required to make as many
sandwiches from 16 slices of bread?
A8
B16
C40
D32
8 slices of cheese are required to make 8 ham sandwiches from 16 slices of bread based on the stoichiometry of the reaction.
What is the balanced equation of the production of ham sandwich?The balanced equation of the production of ham sandwich is given below:
[tex]2H + C +T+5P+ 2B \rightarrow H_2CTP_5B_2 \\ [/tex]
From the stoichiometry of the reaction, 2 slices of bread and 1 slice of cheese are required to make 1 atm sandwich.
There are 16 slices of bread present to make ham sandwich.
Number of slices of cheese required = 16/2 = 8 slices.
Therefore, 8 slices of cheese are required.
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A 100g sample of Carbon-14 has a half-life of 5 years. How much Carbon-14 is left after 10 years?
Answer: The amount of carbon-14 left after 10 years is 25 g
Explanation:
Formula used :
[tex]a=\frac{a_o}{2^n}[/tex]
where,
a = amount of reactant left after n-half lives = ?
[tex]a_o[/tex] = Initial amount of the reactant = 100 g
n = number of half lives =[tex]\frac{\text {given time}}{\text {half life}}=\frac{10}{5}=2[/tex]
Putting values in above equation, we get:
[tex]a=\frac{100g}{2^2}[/tex]
[tex]a=\frac{100g}{4}=25g[/tex]
Therefore, the amount of carbon-14 left after 10 years is 25 g
What is the coefficient of MnO2when you balance the equation for this redox reaction? KCN( aq) + KMnO4( aq) + H2O( l) → KCNO( aq) + MnO2( s) + KOH( aq)
Answer:
2MnO2 (s)
Explanation:
3KCN(aq) + 2KMnO4(aq) + 1H2O(l) → 3KCNO(aq) + 2MnO2(s) + 2KOH(aq)
Reactants:
K: 5
C: 3
N: 3
Mn: 2
O: 9
H: 2
Products:
K: 5
C: 3
N: 3
Mn: 2
O: 9
H: 2
Identify the missing particle in the following nuclear reaction:
4219 K +
Answer:
427.50
Explanation:
The question requests for the missing particle in a nuclear reaction involving the Potassium isotope. Unfortunately, the reaction is incomplete. Nonetheless, the conservation laws of atomic number and atomic mass would be employed to find the missing particle if the equation was complete.
Explanation:In this nuclear reaction, both the atomic number and the atomic mass must be conserved. For atomic numbers (proton numbers), you add the atomic numbers on one side of the equation and set it equal to the sum of atomic numbers on the other side. The same thing applies to atomic mass (proton + neutron numbers). However, the nuclear reaction is not complete.
This question is seeking to determine the missing particle in this nuclear reaction involving potassium (K). The missing part of the nuclear equation would help us determine the product particles after a certain type of nuclear decay. Unfortunately, the reaction is not completely given, if it were we could utilize conservation laws to identify the missing particle.
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Determine which elements or compounds are missing from the following reaction equation: hydrogen + ________ → water
Answer:
Oxygen
Explanation:
Water's formula is H20. Which is two hydrogen and one oxygen.
Explain what domain would best be represented by the "?" in the diagram.
A) Eukarya because the organisms are all eukaryotic.
B) Eukarya because the organisms are all prokaryotic.
C) Bacteria because some of the organisms are autotrophs.
D) Archaea because the organisms are all diverse bacteria.
The correct answer is 'Eukarya because the organisms are all eukaryotic' since the organisms mentioned have cells with nuclei. Bacteria and Archaea are both prokaryotic and do not contain organisms with eukaryotic cells.
Explanation:The correct answer to the question is A) Eukarya because the organisms mentioned are all eukaryotic. This means that the cells of these organisms contain nuclei. The domain Eukarya includes diverse groups such as animals, plants, fungi, and protists. These kingdoms are distinguished by the presence of eukaryotic cells, which differentiate them from prokaryotic cells found in the other two domains, Bacteria and Archaea, both of which lack a nucleus. Bacteria and Archaea are known as prokaryotes and often consist of single-celled organisms. Eukarya, on the other hand, can consist of both unicellular and multicellular organisms. Therefore, Option B 'Eukarya because the organisms are all prokaryotic' is incorrect as eukaryotes have a nucleus. Option C 'Bacteria because some of the organisms are autotrophs' is not correct either since autotrophy is not exclusive to Bacteria and does not define domain classification on its own. Lastly, Option D 'Archaea because the organisms are all diverse bacteria' is incorrect because Archaea is a separate domain, and it encompasses organisms that are genetically distinct from bacteria and eukaryotes, despite their prokaryotic cell structure.
Select all the correct location on the image.
The image shows a model of a nuclear reaction. Which objects could hit other atoms, producing a chain reaction?
All the foursingle neutron /proton in the image coming out of the chain reactions and bombarding are responsible of producing a chain reaction.
What is a nuclear reaction ?
It is the change in the identity or characteristics of an atomic nucleus, induced by bombarding it with an energetic particle.
The bombarding particle may be an alpha particle, a gamma-ray photon, a neutron, a proton, or a heavy ion.
In the given image of a nuclear reaction the objects which could hit other atoms, producing a chain reaction are all the four single neutron /proton coming out of the chain reactions and bombarding.
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Answer:
Picture of model of a nuclear reaction attached.
Explanation:
How much heat is required to heat 9.61g of ethanol (CH3CH2OH) from 24.10C to 67.30C?
Answer:
a.)
To warm the liquid from 35°C to 78°C:
(2.3 J/g-K) x (42.0 g) x (78 - 35) = 4154 J
To vaporize the liquid at 78°C:
(38.56 kJ/mol) x (42.0 g C2H5OH / 46.06867 g C2H5OH/mol) = 35.154 kJ
Total:
4.154 kJ + 35.154 kJ = 39.3 kJ
b.)
To warm the solid from -155°C to -114°C:
(0.97 J/g-K) x (42.0 g) x (-114°C - (-155°C)) = 1670 J
To melt the solid at -114°C:
(5.02 kJ/mol) x (42.0 g C2H5OH / 46.06867 g C2H5OH/mol) = 4.5766 kJ
To warm the liquid from -114°C to 78°C:
(2.3 J/g-K) x (42.0 g) x (78 - (-114)) = 18547 J
To vaporize the liquid at 78°C:
35.154 kJ (as in part a.)
Total:
1.670 kJ + 4.5766 kJ + 18.547 kJ + 35.154 kJ = 59.9 kJ
Explanation:
1021.27 J heat is required to heat 9.61g of ethanol from 24.1⁰C to 67.3⁰C
What is Specific Heat?The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.
It is a measure of how much energy it takes to raise the temperature of a substance. It is the amount of heat necessary to raise one mass unit of that substance by one temperature unit.
It is given by the formula -
Q = mcΔT
where, Q = amount of heat
m = mass
c = specific heat
ΔT = Change in temperature
Given,
Mass of ethanol = 9.61g
Initial temperature = 24.1⁰C
Final temperature = 67.3⁰C
Q = mcΔ T
= 9.61 × 2.46 × ( 67.3 - 24.1)
= 1021.27 J
Therefore, 1021.27 J heat is required to heat 9.61g of ethanol from 24.1⁰C to 67.3⁰C
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A gas is confined to a steel tank with a fixed volume . At 293 K, the gas exerts a pressure of 8.53 atm. After heating the tank , the pressure of the gas increases to 10.4 atm. What is the temperature of the heated gas?
Answer: The temperature of the heated gas is 357 K
Explanation:
To calculate the final temperature of the system, we use the equation given by Gay-Lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.
Mathematically,
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
where,
[tex]P_1\text{ and }T_1[/tex] are the initial pressure and temperature of the gas.
[tex]P_2\text{ and }T_2[/tex] are the final pressure and temperature of the gas.
We are given:
[tex]P_1=8.53atm\\T_1=293K\\P_2=10.4atm\\T_2=?[/tex]
Putting values in above equation, we get:
[tex]\frac{8.53}{293K}=\frac{10.4}{T_2}\\\\T_2=357K[/tex]
Hence, the temperature of the heated gas is 357 K
The current in a closed circuit measures 80 amps. The resistance through a clock connected in the circuit is 2 ohms. What is the voltage of the circuit?
a
40 volts
b
110 volts
c
160 volts
d
60 volts
the subject is SCIENCE
Two scientists made the same observation during an investigation. Since their explanations differed about the observation, they
made additional observations. Why would more observations be helpful for this investigation?
A)
More observations will show both scientists' explanations are not correct.
B)
More observations are needed to show both scientists' explanations are
correct
More observations will prove the scientists' investigation was done
incorrectly.
2)
More observations could help resolve differences in the scientists
explanations.
Answer:
more observations could help resolve differences in the scientists explanations
Explanation:
Making additional observations is crucial when scientists have differing explanations for an observation. More observations provide more data points, increasing the validity of their findings, and can help resolve differences by giving a more comprehensive understanding of the situation.
Explanation:When two scientists make differing explanations about an observation, making more observations is necessary to better understand the event or phenomenon under investigation. Additional observations provide more data points, which add validity to their findings and may lead to a consensus if they consistently show a particular trend. Through additional observations, they can eliminate potential biases or errors that may have occurred in their initial observation. Consequently, more observations might help in resolving differences in the scientists' explanations due to a better, more comprehensive understanding of the observation with varied perspectives.
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For an Ohmic conductor, tripling the voltage without changing the resistance will cause the current to
A.
increase by a factor of 9.
B.
decrease by a factor of 9.
C.
increase by a factor of 3.
D.
decrease by a factor of 3.
Answer:
a
Explanation:
Why are prefixes not used in naming ionic compounds?
Answer:
Since we can't utilize charges to make sense of what number of every particle we have (as we did with ionic mixes), we need to determine with prefixes mono-, di-, tri-, tetra, penta-, hexa-,, etc.
What advantage does gasoline have over electricity for cars?
Final answer:
Gasoline has a higher energy density than electricity stored in lithium-ion batteries, enabling more energy to be carried per unit of weight. Gasoline vehicles can refuel quickly, offering convenience for long-distance travel, while electric vehicles require longer recharge times. Additionally, gasoline's safety profile is relatively high given its energy content, as it burns rather than explodes.
Explanation:
One of the main advantages that gasoline has over electricity for powering cars is its higher energy density. Gasoline contains approximately 13 kWh/kg, while the energy density of lithium-ion batteries is about 0.2 kWh/kg, which is substantially lower. This means that gasoline can deliver more energy per unit of weight than batteries can, making it a more energy-dense fuel source.
An additional advantage is the rapid refueling capability of gasoline vehicles. A car can fill its tank with gasoline at a rate of 15 MW, allowing it to be ready for further travel in a matter of minutes, whereas electric cars often require hours to fully recharge. This convenience factor is a significant benefit for long-distance travel or in situations where quick refueling is necessary.
Safety is another aspect where gasoline has an advantage. Although gasoline is flammable, it is not as explosive as one might think—the vapor mix with oxygen burns rather than explodes, making it relatively safe for an energy source with such high energy content.
1. What happens when you dissolve acid in water?
a. Positive hydronium ions (H3O+) are released
b. Nothing happens
c. No answer text provided.
d. Negative hydroxide ions (OH-) are released
2. A hydronium ion is like a(n) ______ molecule with an extra hydrogen atom.
a. vinegar
b. water
c. acid
d. base
When you dissolve acid in water positive hydronium ions are released. Therefore, the correct option is option A.
What is acid?Any material that when dissolved in water has an acidic taste, may alter the color of some indicators (such as reddening blue litmus paper), can react with some metals (such as iron) to release hydrogen, can combine with bases to produce salts, and can accelerate some chemical changes (acid catalysis).
Acids are examples of both organic chemicals that belong towards the carboxyl group, sulfonic acid, as well as phenol groups as well as the inorganic substances referred as the mineral acids, such as sulfuric, nitric, hydrochloric, as well as phosphoric acids. When you dissolve acid in water positive hydronium ions are released.
Therefore, the correct option is option A.
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i need help with this
Protons are located in the nucleus of the atom along with neutrons, have a positive charge, and a mass of 1.673 x [tex]10^{-27}[/tex] kg.
What is the relationship between Earth's temperature and the number of sunspots that occur?
Answer:
When there is an increased number of sun spots, it means the surface temperature is decreased which will decrease the temperature of the Earth's surface as well.
Explanation:
Sunspots are temporary phenomena on the Sun's photosphere that appear as spots darker than the surrounding areas. They are regions of reduced surface temperature caused by concentrations of magnetic field flux that inhibit convection. Sunspots usually appear in pairs of opposite magnetic polarity.
Answer:
A i took the test
Explanation:
good luck ;)
If the pressure of a gas is 1.0 atm, the volume is 2.0 L and the temperature is 300 k, how many mols (n) of gas are in the container
Answer: The moles of gas are in the container are 0.08
Explanation:
According to ideal gas equation:
[tex]PV=nRT[/tex]
P = pressure of gas = 1.0 atm
V = Volume of gas = 2.0 L
n = number of moles = ?
R = gas constant =[tex]0.0821Latm/Kmol[/tex]
T =temperature =[tex]300K[/tex]
[tex]n=\frac{PV}{RT}[/tex]
[tex]n=\frac{1.0atm\times 2.0L}{0.0821L atm/K mol\times 300K}=0.08moles[/tex]
Thus the moles of gas are in the container are 0.08
think about the statement "there is no new water on earth" write at least 5 sentences describing how there can be no new water on earth, but the earth doesn't run out of water.
How does litmus paper identify a base
A base turns red litmus blue. Litmus paper is paper that has been treated with a specific indicator, a mixture of 10 to 15 natural dyes that turns red in response when the pH is acidic, and blue when it is basic.
Please need asap. 50 points
Answer:
just do the lab or what ever
Explanation:
because your just taking notes and taking data
Part
A loaf of bread bakes in an oven. The bread is on a rack about one foot above the heat
source. However, the top of the bread cooks just as fast as the bottom. How is heat being
added to the bread?
Explanation:
the convection currents in the oven produced by the heat, cooks both the bottom and the top at the same rate.
Answer:
Explanation:
The air is heated by the heat source in the oven. The hot air rises, surrounds the bread, and heats the bread on all sides.
Will P and O2 share or transfer electrons?
P + O2 →P4,O10
Answer:
They will share electrons .
Explanation:
When P and O2 reacts, they will share electrons as both of the elements are non-metals.
Only metal elements such as K , Na , Ca , etc. can transfer electrons to the other non-metal elements.
Which diagram shows electrons violating the Pauli exclusion principle? A box contains an up arrow.A box contains an up arrow.A box contains an up arrow. A box contains an up and a down arrow.A box contains an up and a down arrow.A box contains an up and a down arrow. A box contains an up and a down arrow.A box contains 2 up arrows.A box contains 2 up arrows. A box contains an up and a down arrow.A box contains an up and a down arrow.A box contains an up arrow.
Answer:
C
Explanation:
The diagram which shows electrons violating the Pauli exclusion principle is: C. a box containing an up and a down arrow and 2 other up arrows.
What is the Pauli exclusion principle?The Pauli exclusion principle can be defined as a principle which states that no two electrons (fermions) in a single atom can have the same values for all four (4) of their electronic quantum numbers.
Furthermore, this principle states that the orbital of an atom can only contain a maximum of two electrons, and they must have opposing spin orientations.
In conclusion, the diagram which shows electrons violating the Pauli exclusion principle is a box containing an up and a down arrow and 2 other boxes with 2 up arrows, that are having the same spin orientations as shown.
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Which biome is characterized as dry with temperature ranging from hot to cold and little plant life? *
Estuary
Tundra
Desert
Grassland
Answer:
c . Desert
Explanation:
desert biome is character as a drive with temperature ranging from Hot cold and little plant life .
Answer:
desert
Explanation:
the desert does not have a diverse community with animals, is very dry with little precipitation, and is usually incredibly hot but has a cold/warm temperature at night in the winter.
Science Question:
Why does the same side of the moon always face Earth?
The rotational period of the moon is different than one revolution around Earth.
The rotational period of the moon is equal to one revolution around Earth.
The rotational period of Earth is the same as that of the moon.
The rotational period of Earth is equal to one revolution around Earth.
Answer:
The rotational period of the moon is equal to one revolution around Earth.
I think this is the answer am not that positive.
Explanation
Only one side of the Moon is visible from Earth because the Moon rotates on its axis at the same rate that the Moon orbits the Earth – a situation known as synchronous rotation, or tidal locking. The Moon is directly illuminated by the Sun, and the cyclically varying viewing conditions cause the lunar phases.
Answer:
The rotational period of the moon is equal to one revolution around the earth
Explanation:
I took the test. Hopes this helps :)
3
Which is visible when an area of the sun's gases are cooler than the surrounding gases?
O sunspots
solar flares
O prominences
O solar winds
Answer:
its sunspots :)
Explanation:
can i pleasee have the brainiest tyty
for my rank
Determine the mass of CO2 and H20 produced after combusting 100 g of acetylene (C2H2).
A. 338.5 g of CO2 and 69.2 g of H20
B. 176 g of CO2 and 36 g of H20
C. 100 g of CO2 and 100 g of H20
D. 400 g of CO2 and 200 g of H20
Answer:
A.
Explanation:
the boiling point is 4172 F