Answer:
0.625 kg
Explanation:
Since 90.6 is 3 half-lives from 30.2 (90.6/30.2 = 3) , divide the initial mass of the sample by 2, and divide that quotient by 2, and divide THAT quotient by 2 to determine how much remains after 3 half-lives.
The mass will remain at 1.6 kg.
How to find the mass after 90.6 years?Mass after t years:
The mass of the elements after t years is given by the following equation:
M(t) = M(0)(1-r)[tex]^{t}[/tex]
The half-life of Cs-137 is 30.2 years.
This means that:
M (30.2) = 0.5 M (0)
M (t) = M (0)(0.9773)[tex]^{t}[/tex]
If the initial mass of the sample is 5 kg, how much will remain after 90.6 years?This is M(151), with M(0) = 100.
Then,
M(90.6) = 5(0.9773)[tex]^{90.6}[/tex]
= 5*0.24
= 1.2 kg
Cesium-137 emits beta particles as it decays to the barium isotope, Ba-137m.
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did the microscope revolutionize surgery
Answer:
Yes
Explanation:
What helps transport proteins made by ribosomes?
If the reactants have a potential energy of 10.2 kJ/mol and the products have a potential energy of 15.7 kJ/mol, what is ΔH?
Answer:
your answer
Explanation:
Think about the systems around you for example you’re reading this text on a computer system write definition for the word system
Answer:
A system is a group of related parts that work together as a whole.
Explanation:
edmentum.
A system is a set of interacting elements regarded as a distinctive entity for the purpose of study or observation. It can be physical like planets in a solar system, abstract like the systems operating in a computer, or organic like our nervous system.
Explanation:A system can be defined as a set of elements that interact with each other and can be considered as a single entity, often for the purpose of study or analysis. This grouping can be physical, such as planets in a solar system, or conceptual, like the motor and visual systems in the human body. Systems, whether isolated, closed, or open, abide by certain laws, including conservation laws. Isolated and closed systems have minimal interactions with their environment, while open systems can exchange energy and/or matter with their surroundings.
Examples of systems can be seen everywhere, from how your computer operates as a system, to natural systems such as your nervous system processing sensory information and controlling your body's functions.
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Which of the following describes a boiling point?
A. Phase change from a solid to a liquid occurring at a specific
temperature and pressure
B. Phase change from a liquid to a gas occurring at a specific
temperature and pressure
c. Phase change from a gas to a liquid occurring at a specific
temperature and pressure
D. Phase change from a solid to a gas occurring at a specific
temperature and pressure
Answer:
Phase change from a liquid to a gas occurring at a specific temperature and pressure
Explanation:
Boiling is a physical process in which a substance changes its state from liquid to vapor state.
In this context ,boiling point is the threshold temperature at which changes of state from liquid to vapor occurs. The boiling point also depends upon atmospheric pressure of environment as well. For the same substance, boiling point at two different pressure will differ significantly.
For example : Boiling point of water at sea level is 100 degree Celsius
while at 6,250 ft , Boiling point of water is 93.4 degree Celsius.
Based on above discussion option B Phase change from a liquid to a gas occurring at a specific temperature and pressure is the correct answer.
Answer: B) Phase change from a liquid to a gas occurring at a specific temperature and pressure.
Is it small intestine or Stomach or Rectum or Bladder
Answer: C. Rectum
Explanation:
Molar mass c3h8
Total molar mass for carbon atoms
Total molar mass for hydrogen atoms
Carbon percent composition
Hydrogen percent composition
Answer:
1. 44.11 g
2. 36.03 g
3. 8.08 g
4. 81.7%
5. 18.3%
Explanation:
1. 12.01+12.01+12.01+1.01+1.01+1.01+1.01+1.01+1.01+1.01+1.01=44.11
2. 12.01×3= 36.03
3. 1.01×8= 8.08
4.(36.03/44.11)×100= 81.7%
5. (8.08/44.11)×100= 18.3%
The molar mass of C3H8 is 44.094 g/mol. The carbon percent composition is 81.72% and the hydrogen percent composition is 18.28%.
Explanation:The molar mass of C3H8 (propane) can be calculated by adding up the atomic masses of the atoms in the molecule. Carbon has a molar mass of 12.01 g/mol, and there are 3 carbon atoms in C3H8, so the total molar mass for carbon atoms is 12.01 g/mol x 3 = 36.03 g/mol. Hydrogen has a molar mass of 1.008 g/mol, and there are 8 hydrogen atoms in C3H8, so the total molar mass for hydrogen atoms is 1.008 g/mol x 8 = 8.064 g/mol.
The percent composition can be calculated by dividing the molar mass for each element by the total molar mass of C3H8. The carbon percent composition is (36.03 g/mol / 44.094 g/mol) x 100% = 81.72%. The hydrogen percent composition is (8.064 g/mol / 44.094 g/mol) x 100% = 18.28%.
An electric current is flowing through the cord below.
What will happen to this current if a magnet is brought near the cord?
A.
It will exert a force on the electric current.
B.
The resistance of the wire will decrease.
C.
The electric current will stop flowing.
D.
It will exert a force on the voltage.
Answer:
A
Explanation:
Answer:
es la A
Explanation:
Disturbed soil is when top soil and subsoil are mixed.
O
True
U
False
Answer:
true
Explanation:
The A horizon, known as the topsoil, is essential for plant production due to its rich organic content, while the B horizon, or subsoil, is denser and stores inorganic nutrients.
Explanation:Topsoil is considered the A horizon, consisting of partially decayed organic matter that enhances soil moisture retention, while the Subsoil is the B horizon, a dense layer with inorganic nutrients accumulation.
In understanding soil composition and structure, it's crucial to identify the different layers or horizons that make up the soil profile. The topsoil is referred to as the A horizon, which is the layer where the soil possesses a mixture of organic material and inorganic products of weathering. This horizon is typically dark due to the presence of organic matter, making it highly crucial for plant production as it retains water and facilitates oxygen diffusion necessary for root respiration. Below the topsoil lies the subsoil, known as the B horizon. This layer accumulates mostly fine material that has been translocated downwards from the A horizon, making it denser. The subsoil is critical for the storage of inorganic nutrients but is lighter in color and has fewer organic materials compared to the topsoil.
Determine the empirical formula of a compound that is 39.99% carbon, 53.28% Oxygen and 6.73% Hydrogen
Answer:
CH2O
Explanation:
Pretend you have a 100 gram sample.
39.99 g C * (1 mol/12.01 g) = 3.33 moles C
53.28 g O * (1 mol/16 g) = 3.33 moles O
6.73 g H * (1 mol/ 1.008 g) = 6.676 moles H
You can see from this data that there are double the number of moles of H compared to the moles of C and O.
To find the empirical formula, you divide all the moles by the least number of moles. In this case, the least number of moles is 3.33. So for carbon and oxygen, divide 3.33 by 3.33... this equals 1. For H, divide 6.676 by 3.33... this is about equal to 2. Therefore, the empirical formula is CH2O. :)
Hope this was helpful!
Answer: [tex]COH_2[/tex]
Explanation:
39.99% C
53.28% O
6.73% H
First step:
Change % to g
39.99g C
53.28g O
6.73g H
Second step:
Calculate the number of g/mol using atomic mass.
[tex]39.99gC(\frac{1mol}{12g} )=3.332mol[/tex]
[tex]53.28gO(\frac{1mol}{16g})=3.330mol[/tex]
[tex]6.73gH(\frac{1mol}{1g} )=6.73mol[/tex]
Third step:
Determine the smallest number of moles and divide each compound by it. When you get the result, simply put the whole number, not decimals.
[tex]C=\frac{3.332mol}{3.330mol}=1[/tex]
[tex]O=\frac{3.330mol}{3.330mol} =1[/tex]
[tex]H=\frac{6.73mol}{3.330mol}=2[/tex]
Fourth step:
Rewrite those number under the compounds.
This empirical formula should be: [tex]COH_2[/tex]
5. The image above represents a cell going
through meiosis. How do you know the
image does not represent mitosis?
A Mitosis only has one cell division set.
B Mitosis only occurs in
reproductive
cells, such as the ones in the picture.
C Mitosis is involved in the production of
haploid sex cells.
D Mitosis divides cells into eight cells, not
four.
Answer:
The correct answer is option A, that is, mitosis only has one cell division set.
Explanation:
The two kinds of nuclear division that takes place at the time of cell differentiation are meiosis and mitosis. In the process of mitosis, the cells of the body get divide, while in meiosis the sex cells are differentiated.
While going through the process of mitosis, the cell divides only one time, on the other hand, during meiosis a cell divides two times. After going through mitosis production of two diploid daughter cells takes place, while after going through meiosis generation of four haploid daughter cells takes place. Thus, it is clear from the diagram that the process of meiosis is taking place, as the formation of four haploid cells is taking place as the cell is dividing two times.
Some plant seeds are adapted to sprout with a limited amount of water. For what environmental change are these seeds most likely adapted? earthquake tsunami drought global warming
Answer:
drought
Explanation:
In an ecosystem, some plant seeds are adapted to sprout with a limited amount of water. They are adapted to drought.
What is an ecosystem?
Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.
Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.
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What must occur in order for a gas-discharge lamp to produce light?
On top of Mt. Yale in Colorado (elevation 14,202 feet), you step on a scale and weigh 183 pounds, using the same scale in New Orleans (elevation 4 feet) you would weigh ?
A. More than on top of Mt. Yale
B. Less than on top of Mt. Yale
C. The same as on top of Mt. Yale
Please help.. an explanation would really help as well..
On top of Mt. Yale in Colorado (elevation 14,202 feet), you step on a scale and weigh 183 pounds, using the same scale in New Orleans (elevation 4 feet) you would weigh more than on top of Mt. Yale.
Hence, option A is correct.
What are pounds?Pound, unit of avoirdupois weight, equal to 16 ounces, 7,000 grains, or 0.45359237 kg, and of troy and apothecaries' weight, equal to 12 ounces, 5,760 grains, or 0.3732417216 kg. The Roman ancestor of the modern pound, the libra, is the source of the abbreviation lb.
183 is to 14202 as x is to 4
183/14202 = x/4
14202x = 183(4)
x = 183(4)/14202
x = 0.0515 pounds
Hence, option A is correct.
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Using general tendencies and the chart given in the introduction, predict the most likely mode of decay of each of the following radioactive isotopes.
Drag the appropriate items to their respective bins.
Note: Based on the valley of stability, the following processes generally tend to produce more stable neutron-to-proton (n/p) ratios:
Nuclei with Z≥84 tend to undergo α emission.
Nuclei with high n/p ratios undergo β ( 0−1e) emission.
Heavy nuclei with low n/p ratios are more likely to undergo electron ( 0−1e) capture.
Light nuclei with low n/p ratios are more likely to undergo positron (01e) emission.
The classification "high" or "low" n/p ratio can be determined by finding the coordinates on the graph that correspond to the number of protons (x or horizontal value) and neutrons (y or vertical value) in a given isotope. Then, observe whether this set of coordinates is above, within, or below the stability valley.
My Effort to Solve it myself:
K-47, Hg-190, Th-232, Na-20, I-137
# of.... p n order of greatest atomic mass
K: 19 28 4
Hg: 80 110 2
Th: 90 142 1
Na: 11 9 5
I: 53 84 3
Answer:
K-47 undergoes beta decay
Hg-190 undergoes electron capture or alpha decay
Th-232 undergoes alpha decay
Na-20 undergoes positron emission
I-137 undergoes beta decay
Explanation:
Stability of a nucleus is decided by the neutron /proton (n/p) ratio. For lower elements of atomic number 1-20, n/p=1. Elements with higher atomic numbers tend to have a slight excess of neutrons to reduce the repulsive forces between the protons.
Beta emission decreases the n/p ratio, positron emission increases the n/p ratio, electron capture increases the n/p ratio and alpha decay increases the n/p ratio.
Note that a nucleus may undergo several decay processes before stable nucleus (nuclei) is/are formed.
The decay mode of radioactive isotopes is primarily determined by the atomic number (Z) and the neutron-proton (n/p) ratio. For example, K-47 and Hg-190, with high n/p ratios, would decay through β emission. Th-232, having Z≥84 and a high n/p ratio would undergo α emission. Na-20, being a light nucleus with a low n/p ratio would do positron emission, and I-137 with high n/p ratio would do β emission.
Explanation:Based on our understanding of nuclear stability and decay, radioactive isotopes decay in a way that brings them closer to a state of stability. They do this by adjusting their neutron to proton ratios (n/p) through various forms of decay. The mode of decay depends largely on the Z number (atomic number) and the n/p ratio.
K-47 (19 protons, 28 neutrons) has a high n/p ratio, thus it will likely undergo β ( 0−1e) emission.Hg-190 (80 protons, 110 neutrons) also has a high n/p ratio and is likely to decay through β ( 0−1e) emission. Th-232 (90 protons, 142 neutrons), with Z≥84 and a high n/p ratio, is most likely to undergo α emission. Na-20 (11 protons, 9 neutrons) is a light nuclei with a low n/p ratio, so it will most likely undergo positron (01e) emission. I-137 (53 protons, 84 neutrons) has a relatively high n/p ratio and would therefore most likely undergo β ( 0−1e) emission.Learn more about Radioactive Decay here:
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Pitchblende is ore of _____.
plutonium
curium
uranium
radium
Answer:
Uranium
Explanation:
Answer:
Uranium
Explanation:
You have a 5.0 L balloon that you bought in Denver(0.85 atm). If you take
that balloon back to sea level, where the pressure is 1.0 atm, what will the
new volume of the balloon be?
Answer:
New volume of the balloon at sea level (V1) = 4.25 L
Explanation:
Given:
Present volume (V) = 5 L
Present pressure (P) = 0.85 atm
Pressure at sea level (P1) = 1 atm
Find:
New volume of the balloon at sea level (V1) = ?
Computation:
According to Boyles law:
⇒ P × V = P1 × V1
⇒ 0.85 × 5 = 1 × V1
⇒ 4.25 L = V1
New volume of the balloon at sea level (V1) = 4.25 L
Ice melting is not a chemical change because __________.
A) a new reactant is formed
B) a new substance is not formed
C) a precipitate is no present
D) there is increased activation energy
Answer:
B.) A new substance is not formed
Explanation:
hope this helps
Ice melting is not a chemical change because a new substance is not formed.
What is a chemical change?Chemical changes are defined as changes which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical change.
There are several characteristics of chemical changes like change in color, change in state , change in odor and change in composition . During chemical change there is also formation of precipitate an insoluble mass of substance or even evolution of gases.
There are three types of chemical changes:
1) inorganic changes
2)organic changes
3) biochemical changes
During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.
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To measure temperature scientists used?
What color on the pH paper indicates that an acid has formed?
Answer:
red
Blue litmus paper turns red under acidic condition
Explanation:
Answer: Acidic Ph Levels: Lime green, yellow, orangle, and red
Explanation:
Alkaine Ph Levels: Purple, blue, and light green.
Neutral Ph Level: A bright green.
Acidic Ph Levels: Lime green, yellow, orangle, and red
Therefore, once the Ph paper indicates if the color is lime green, yellow, orangle, or red then that means it's acidic.
I hope this helps!
In your own words, describe how a hurricane forms. (5 points)
Which of the following factors would negatively impair the water quality in a watershed? I. irresponsible use of industrial chemicals II. increase of the amounts of fertilizers and pesticides used on farmlands III. decrease in sewage discharge into lakes and rivers
II and III only
I, II, and III
I and II only
I only
Answer:
1 and 2 only
Explanation: These will make a bad impact on water.
Consider the balanced equation below.
N2H4 + 2H2O2 → N2 + 4H2O
What are the mole ratios of hydrazine (N2H4) to hydrogen peroxide (H2O2) and hydrazine to water?
1:2 and 1:4
1:3 and 1:4
1:2 and 3:5
1:3 and 3:5
Answer:
A.)
Explanation:
From the balanced equation, it is clear that the mole ratio of the hydrazine to hydrogen peroxide is 1 :2 and that of hydrazine to water is
1 :4.
What is mole ratio ?The mole ratio is the ratio between the number of moles of a reactant to the number of moles of another reactant.
The balanced chemical equation for the reaction is:
N2H4 + 2H2O2 → N2 + 4H2O
From the equation, the mole ratio of hydrazine (N2H4) to hydrogen peroxide (H2O2) is 1:2, which means that for every one mole of hydrazine used, two moles of hydrogen peroxide are used.
Similarly, the mole ratio of hydrazine (N2H4) to water (H2O) is 1:4, which means that for every one mole of hydrazine used, four moles of water are produced.
Therefore, the correct option is 1:2 and 1:4.
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In this experiment, you will measure all masses in
kilograms. Convert the book's mass to kilograms.
Answer:
0.498 kg
Explanation:
Answer:
The first answer is 498
The second answer is 0.498
Explanation:
14. How many grams of NaCl are contained in 0.350 kg of a
0.238 m solution of sodium chloride?
83.3 g
0
4.87 g
4.87 g
O
13.9 g
o
1.43 g
Answer:
4.87g
Explanation:
Step 1:
Data obtained from the question. This includes the following:
Mass of solution = 0.35kg
Molality = 0.238 m
Mass of NaCl =..?
Step 2:
Determination of the number of mole of NaCl in the solution.
Molality of a solution is simply defined as the mole of solute per unit kg of the solvent. It is given as:
Molality = mol of solute /mass of solvent (kg)
With the above formula, we calculate the mole of NaCl present in the solution as follow:
Molality = mol of solute /mass of solvent (kg)
0.238 = mol of NaCl /0.35
Cross multiply
mol of NaCl = 0.238 x 0.35
mol of NaCl = 0.0833 mol
Step 3:
Determination of the mass of NaCl in 0.0833 mol of NaCl.
This is illustrated below:
Number of mole NaCl = 0.0833 mol
Molar Mass of NaCl = 23 + 35.5 = 58.5g/mol
Mass of NaCl =..?
Mass = number of mole x molar Mass
Mass of NaCl = 0.0833 x 58.5
Mass of NaCl = 4.87g
Therefore, 4.87g of NaCl is contained in the solution.
why are viruses (specifically) so dangerous?
Answer:
Over 700,000 lives are taken by the AIDs virus every year. Hepatitis C claims the lives of over 200,000 people each year and haemorrhagic fevers caused by viruses such as Ebola have resulted in over 20,000 deaths.
Explanation:
Nitrogen gas (112 g) reacts with hydrogen gas to produce 40.8 g of ammonia according to the following
equation:
N2 + 3 H2 → 2 NH3
Calculate the percent yield of ammonia.
Answer:
%yield of NH₃ = 30%
Explanation:
Actual yield of NH₃ = 40.8g
Theoretical yield = ?
Equation of reaction
N₂ + 3H₂ → 2NH₃
Molar mass of NH₃ = 17g/mol
Molarmass of N = 14.00
2 molecules of N = 2 * 14.00 = 28g/mol
Number of moles = mass / molar mass
Mass = number of moles * molar mass
Mass = 1 * 28.00 = 28g of N₂ (the number of moles of N₂ from the equation is 1).
From the equation of reaction,
28g of N₂ produce (2 * 17)g of NH₃
28g of N₂ = 34g of NH₃
112g of N₂ = x g of NH₃
X = (112 * 34) / 28
X = 136g of NH₃
Theoretical yield = 136g of NH₃
% yield = (actual yield / theoretical yield) * 100
% yield = (40.8 / 136) * 100
% yield = 0.3 * 100
% yield = 30%
For a social experiment I have to take peoples guesses so PLEASE ANSWER
Someone polled 30,000 Floridians to see what their biggest fear is. Figure out the most common
A.Tourist Drivers
B.Palmetto Bugs
C.Snakes
D.Fire Ants
E.Sinkholes
F.Sharks
G.Broken A/C
H.Alligators
I.Hurricanes
Answer:
I. hurricanes
Explanation:
Answer:
C
Explanation:
Reptiles generally pose some sort of natural bewilderment to most people.
A healthy breakfast supplies 230.000 calories how many joules is that same breakfast? 4.18
Joules i calone
Since 4.184 Joules equals one calorie, simply we need to make a cross multiply equation.
4.184J/1cal=x J/230000cal
Then we can multiply the crosses and set them equal to each other. 4.184(230000)=1x
962320=x
The healthy breakfast supplies 962320 joules worth of food.
A sample of gas starts at 1.00 atm, 0.00 degrees Celsius, and 30.0 mL. What is the volume if the temperature increases to 27.0 degrees Celsius and the pressure increases to 2 atm?
Answer:
16.48mL
Explanation:
The following data were obtained from the question:
Initial pressure (P1) = 1 atm
Initial temperature (T1) = 0°C = 0°C + 273 = 273K
Initial volume (V1) = 30mL
Final temperature (T2) = 27°C = 27°C + 273 = 300K
Final pressure (P2) = 2atm
Final volume (V2) =..?
Applying the general gas equation, the final volume of the gas can be obtained as follow:
P1V1/T1 = P2V2/T2
1 x 30/273 = 2 x V2/300
Cross multiply to express in linear form
273 x 2 x V2 = 30 x 300
Divide both side by 273 x 2
V2 = (30 x 300)/(273 x 2)
V2 = 16.48mL
Therefore, the new volume of the gas is 16.48mL
The volume of a sample of gas that starts at 1.00 atm, 0.00 degrees celsius, and 30.0 mL is 16.48mL. Details about volume can be found below..
How to calculate volume?The volume of an ideal gas can be calculated by using the following formula:
P1V1/T1 = P2V2/T2
Where;
P1 = initial pressureP2 = final pressureT1 = initial temperatureV1 = initial volumeV2 = final volumeT2 = final temperature1 × 30/273 = 2 × V2/300
0.109 = 2V2/300
32.97 = 2V2
V2 = 16.48mL
Therefore, the volume of a sample of gas that starts at 1.00 atm, 0.00 degrees celsius, and 30.0 mL is 16.48mL.
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