Answer:
Every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. Therefore, there must be the same number of atoms of each element on each side of a chemical equation.
Explanation:
YW :)
Cobalt-60, with a half-life of 5.0 days, is used in cancer radiation treatments. A hospital purchases a 30.0g supply of it and stores it on a shelf in a closet. The next time a hospital worker grabs the bottle, though, they find that it only contains 3.75 g remaining! Assuming the bottle had never been opened, how long was the bottle sitting on the shelf before the worked grabbed it?
Answer:
Bottle is sitting on the shelf for 15 days.
Explanation:
Given data:
Co-60 half life = 5 days
Total amount = 30.0 g
Amount left = 3.75 g
Time taken = ?
Solution:
AT time zero = 30 g
AT first half life= 30g /2 = 15 g
At 2nd half life = 15 g/ 2 = 7.5 g
At 3rd half life = 7.5 g/2 = 3.75 g
Now we will calculate the sitting time of bottle.
Half life = Time taken / number of half lives
3× 5 days = time taken
Time taken = 15 days
Bottle is sitting on the shelf for 15 days.
a 25.00 gram sample of ice at0.0c melts and then warms u to 20.0c. how much energy is absorbed? this problem is represented on the heating curve as sections
Ice in a 25.00-gram sample melts at 0.0 °C and subsequently heats to 20.0 °C. The energy taken in is 10.5 KJ. The heating curve in sections 2 and 3 illustrates this issue.
we know that,
melts 25.00g 335J = 8375 J
-1g
warm t=mC\(_{p}\)ΔT=25.00g×4.184 J/g°C×20.0 °C=2092 J
Add together = 10467J=10.47 KJ≅10.5 KJ
Energy is the ability to conduct work in physics. Additionally, there is heat and work, which is energy moving from one body to another. Energy is always identified in accordance with its nature once it has been transferred. Therefore, the heat transported may manifest as thermal energy while work performed may result in mechanical energy.
Motion is a property of all energies. Anybody in motion, for instance, possesses kinetic energy. Even while at rest, a tensioned object like a spring or bow has the capacity to move; this is because of the way it is built.
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what could cause a population of deer to decrease?
Explanation:
more predators, less deers. also starvation, and diseases.
determine the mass of calcium phosphate that can be produced from the reaction of 3.75 g of calcium chloride with 4.25 g of potassium phosphate
The mass of calcium phosphate, Ca₃(PO₄)₂ that can be produced from the reaction of 3.75 g of calcium chloride with 4.25 g of potassium phosphate is 3.11 g
How do i determine the mass of of calcium phosphate produced?Let us begin by obtaining the limiting reactant. This obtained as follow
3CaCl₂ + 2K₃PO₄ → Ca₃(PO₄)₂ + 6KCl
Molar mass of CaCl₂ = 111 g/molMass of CaCl₂ from the balanced equation = 3 × 111 = 333 g Molar mass of K₃PO₄ = 212 g/molMass of K₃PO₄ from the balanced equation = 2 × 212 = 424 gFrom the balanced equation above,
333 g of CaCl₂ reacted with 424 g of K₃PO₄
Therefore,
3.75 g of CaCl₂ will react with = (3.75 × 424) / 333 = 4.77 g of K₃PO₄
From the above calculation, we can see that a higher amount (i.e 4.77 g) of K₃PO₄ than what was given (i.e 4.25 g) is needed to react with 48 g of CaCl₂
Thus, the limiting reactant is K₃PO₄
Finally, we shall determine mass of calcium phosphate, Ca₃(PO₄)₂ produced. Details below:
3CaCl₂ + 2K₃PO₄ → Ca₃(PO₄)₂ + 6KCl
Molar mass of K₃PO₄ = 212 g/molMass of K₃PO₄ from the balanced equation = 2 × 212 = 424 gMolar mass of Ca₃(PO₄)₂ = 310 g/molMass of Ca₃(PO₄)₂ from the balanced equation = 1 × 310 = 310 gFrom the balanced equation above,
424 g of K₃PO₄ reacted to produce 310 g of Ca₃(PO₄)₂
Therefore,
4.25 g of K₃PO₄ will react to produce = (4.25 × 310) / 424 = 3.11 g of Ca₃(PO₄)₂
Thus, the mass of calcium phosphate, Ca₃(PO₄)₂ produced is 3.11 g
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the results of a separation using two-dimension gel electrophoresis are shown here.
The results of the separation using two-dimensional gel electrophoresis reveal the distribution and abundance of proteins in a sample.
Two-dimensional gel electrophoresis is a powerful technique used to separate complex mixtures of proteins based on their isoelectric point (pI) and molecular weight. The first dimension of this technique involves isoelectric focusing (IEF), where proteins are separated based on their charge. A pH gradient is established across the gel, and when an electric field is applied, proteins migrate towards the pH region where their net charge is zero, resulting in their separation according to their pI.
In the second dimension, the proteins from the first dimension gel are placed on top of a polyacrylamide gel, which is then subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). In SDS-PAGE, proteins are separated based on their molecular weight. The proteins from the first dimension gel are now distributed along a single axis according to their pI and separated further by size during electrophoresis.
The resulting gel displays a complex pattern of spots, each representing a specific protein in the sample. By comparing the protein patterns obtained from different samples or conditions, researchers can identify changes in protein expression, post-translational modifications, or protein interactions. These results can provide insights into cellular processes, disease mechanisms, and biomarker discovery.
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a bod test was conducted using multiple bottles containing 30 ml of wastewater and 270 ml of dilution water and a nitrification inhibitor so only carbonaceous bod utilization would occur in the test. the average initial do of the mixture was 9.0 mg/l. on day 5 the average do in the bottles tested measured 4 mg/l. after 30 days the average do in the bottles tested measured 2 mg/l and after 50 days the average do in the bottles tested again measured 2 mg/l. a nitrification inhibitor was added to the initial mixture, so only carbonaceous bod utilization was occurring in the test. a) what is the bod 5 of the wastewater? b) what is the ultimate carbonaceous bod? c) how much bod remains after 5 days? d) based on the data above, estimate the reaction rate constant k (1/day)
a) The BOD5 of the wastewater can be calculated as follows:
Initial DO - Final DO = BOD5
9.0 mg/l - 4.0 mg/l = 5.0 mg/l (BOD5)
b) The ultimate carbonaceous BOD can be estimated by assuming that all the BOD has been utilized. Therefore, it is equal to the BOD5 value.
Ultimate carbonaceous BOD = BOD5 = 5.0 mg/l
c) The amount of BOD remaining after 5 days can be calculated as follows:
Initial DO - DO after 5 days = BOD remaining
9.0 mg/l - 2.0 mg/l = 7.0 mg/l (BOD remaining after 5 days)
d) To estimate the reaction rate constant k, we can use the first-order rate equation:
BODt = BOD5 * e^(-kt)
where BODt is the BOD remaining at time t, and e is the base of the natural logarithm.
Using the data at day 30:
2.0 mg/l = 5.0 mg/l * e^(-k*30)
k = 0.0461 (1/day)
Therefore, the estimated reaction rate constant k is 0.0461 (1/day).
A BOD test was conducted using a mixture of 30 mL wastewater and 270 mL dilution water, with a nitrification inhibitor added. The initial DO was 9.0 mg/L.
a) The BOD5 of the wastewater is calculated by subtracting the DO after 5 days (4 mg/L) from the initial DO (9.0 mg/L), resulting in a BOD5 of 5 mg/L.
b) The ultimate carbonaceous BOD can be determined by subtracting the DO after 30 days (2 mg/L) from the initial DO (9.0 mg/L), giving a value of 7 mg/L.
c) The amount of BOD remaining after 5 days can be determined by subtracting the BOD5 from the ultimate carbonaceous BOD (7 mg/L - 5 mg/L), which equals 2 mg/L.
d) To estimate the reaction rate constant k (1/day), more data points are needed. Based on the information provided, a reliable estimation of k cannot be made.
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100 Point test please help
Which environmental concern for ecosystems is directly related to the growing urban population of the world?
Climate change
Melting glaciers
Urban runoff
Rising sea levels
Answer:
sorry if this is wrong bt j would say rising sea levels
the double bond in ethene is made up of a pi bond and a sigma bond formed by lateral overlap of two p orbitals
The unhybridized pz orbitals on each carbon overlap to a π bond (pi).The sigma bond framework of the ethylene molecule is produced by the overlap of hybrid orbitals or by the interaction of a hybrid orbital and a 1s hydrogen orbital.
Each carbon still has its unhybridized pz orbital, though. Sigma bond are typically the only types of single bonding between atoms. One sigma bond and two pi bonds make up triple bonds. One sigma () bond makes up a single bond, one and one pi () bond makes up a double bond, and one and two bonds make up a triple bond.
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How many particles are in 23 grams of carbon tetrafloride
Answer:
5.399772727e22 atoms/particles or 5.39 x 10^22 atoms/particles
Explanation:
so to convert you’re going to convert grams to moles and moles to atoms/particles:
grams to moles:
23g CF4 x 1 mol
———— = 0.26136 mol
88g (molar mass of CF4)
moles to atoms/particles:
[2.066 • 10^23 is avogadro's number and is always used to convert to atoms/particles]
0.26136 mol x 2.066 • 10^23
———————
1 mol
this gives you 5.399772727e22 atoms/particles
so 5.399772727e22 atoms/particles or 5.39 x 10^22 atoms/particles for scientific notation
hope this helps :)
The arrows in the chart below represent phase transitions. Three bars are shown labeled Solid, Liquid, and Gas. They are connected by arrows labeled 1 to 6. Arrow 1 points from liquid to gas; arrow 2 from solid to liquid, arrow 3 from solid to gas, arrow 4 from gas to liquid, arrow 5 from liquid to solid, and arrow 6 from gas to solid. Which arrows represent the phase transitions in which heat energy is gained? 1, 2, and 3 2, 3, and 5 3, 4, and 5 4, 5, and 6 Mark this and return
The arrows that represent the phase transitions in which heat energy is gained is : (A). 1, 2 and 3
Meaning of phase transitionsPhase transitions can be defined as the changing of matter from one form to another due to the addition or gaining of heat or due to the removal or loss of heat.
Phase transitions in matter are majorly between three phases which are: Solid, Liquid and Gas.
In conclusion, The arrows that represent the phase transitions in which heat energy is gained is : (A). 1, 2 and 3
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Calculate the average acceleration of a car with a starting velocity of 0 m/s that accelerates to 9
m/s in 3 seconds.
Answer:
3 m/s
Explanation:
I found the unit rate which is 9/3 = 3
calculate the concentration in ppm of lead in a solution that contains 193.0 mg pb per 2.35 kg of solution
The concentration of lead in a solution that contains 193.0 mg pb per 2.35 kg of solution is equals to the 82.13 ppm.
We have, a solution with presence of lead, pb. This solution contains 193.0 mg pb per 2.35 kg of solution. We have to determine the concentration of lead in solution in ppm. The mass fraction of a substance in a mixture/solution is the ratio of the mass of that substance to the total mass of the mixture. Formula of mass fraction is
Mass Fraction (x) = Mass of Salute/Mass of Salution (0)
Now, Mass of lead, pb = 193.0 mg
Mass of solution = 2.35 kg
So, mass fraction, y = 193 × 1/10³ g/2.35 × 10³g
= 82.13/10⁶
Now in ppm , y× 10⁶ ppm
= 82.13 ×10⁶/10⁶ ppm
= 82.13 ppm
Hence, required concentration is 82.13 ppm.
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Name three organelles and explain the function of each.
this is more science
giving 15 points
if 15 grams of carbon is present at the beginning of a reaction,how many grams of carbon will be present in the products?
The law of conservation states that the mass of the element remains the same during the course of the reaction.
The law of reaction conformed by the following:-
Mass of reactantMass of productAccording to the question, the amount of carbon is 15g in the reactant and the amount will remain same at the end of reaction, which is product that is 15g.
Hence, the amount remain same in the reaction that is 15g.
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What is the frequency of a red laser that has a wavelength of 676 mn
The frequency of a red laser that has a wavelength of 676 nm would be 4.43 x \(10^{14\) hertz.
Frequency of wavesThe frequency and wavelength of a wave are related by the following equation:
λf = c
Where λ is the wavelength of the wave in meters, f is the frequency in Hertz, and c is the speed of light in a vacuum.
in this case, λ = 676 nm = 6.76 x \(10^{-7\) m
c = 299,792,458 m/s
Making f the subject of the formula:
f = c/λ
= 299,792,458/6.76 x \(10^{-7\)
= 4.43 x \(10^{14\) hertz
In other words, the frequency of a red laser that has a wavelength of 676 nm would be 4.43 x \(10^{14\) hertz.
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Magnets are classified based upon how they occur either naturally or man made true or false
Answer:
True
Explanation:
Permanent artificial, temporary artificial and natural. They are classified by the way in which they have achieved magnetism and by how long they remain magnetic.
What is the percent, by mass, of water in MgSO4.2H20
Answer:51.1%
Explanation:
Mass percent : It is defined as the mass of the given component present in the total mass of the compound. Formula used : First we have to calculate the mass of and . Mass of = 18 g/mole Mass of = 7 × 18 g/mole = 126 g/mole Mass of = 246.47 g/mole Now put all the given values in the above formula, we get the mass percent of in . Therefore, the mass percent of in is, 51.1%
To produce electricity a generator needs what kind of imput
Answer: Mechanical Energy
Explanation:
To produce electricity, a generator needs an input of mechanical energy. Mechanical energy is a combination of potential energy and kinetic energy. Generators use this to create electricity to power light bulbs, technological devices, and more!
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What can be said about elemental families? how does this help chemists understand how elements react?
On the basis of their chemical and physical characteristics, the elements in the periodic table can be divided into groups or families.
Chemists can predict how elements will interact based on their positions in the periodic table by understanding elemental families. For example, alkali metals such as sodium and potassium are extremely reactive because they have a single valence electron.
Alkali metals, alkaline earth metals, halogens, noble gases, transition metals, and other substances are included in these families.
Because all members of a family have the same number of valence electrons—the outermost electrons involved in chemical bonding—the elements in that family share comparable chemical characteristics.
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which procedure is recommended when a student needs more of a hazardous material
When a student needs more of a hazardous material, the recommended procedure is to follow proper safety protocols and guidelines, including consulting with the instructor or supervisor.
Handling hazardous materials requires careful consideration of safety measures to minimize the risks involved. In this situation, the student should first consult with their instructor or supervisor to communicate their need for more of the hazardous material. The instructor or supervisor can provide guidance on the appropriate procedures to follow, including assessing the necessity for the material and ensuring that the student has the necessary training and knowledge to handle it safely.
It is crucial to understand the risks associated with the hazardous material and follow all safety guidelines and protocols. This may include wearing appropriate personal protective equipment (PPE), working in a well-ventilated area, and using proper storage and disposal methods.
Furthermore, it is important to adhere to any legal requirements or regulations regarding the procurement and handling of hazardous materials. This may involve obtaining the necessary permits or licenses, ensuring compliance with safety standards, and maintaining proper documentation.
By following these recommended procedures, students can ensure their safety and the safety of others while obtaining the required amount of hazardous materials.
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The deflection of earths planetary is example of
Answer:
The Coriolis effect is an apparent deflection in the paths of moving objects caused by Earth's faster speed near the equator than near the poles. In the solar system, the greatest expression of this effect occurs in planetary atmospheres. On Earth, for example, the air around us moves freely above the ground.
Explanation:
Which ions produce similar colors in the flame tests?
Answer:
Two ions that produced similar colors in the flame test were Ca+2 and Sr+2. 3.
Explanation:
The colors are produced when an electron jumps to a higher level and then jump back down.
Ba2+ and Cu2+ and Sr2+ and Li+ were the pair with the similar color. Sr and Li displayed red colors, while Ba and Cu had mild greenish yellowish hues.
Why do some ions in the flame test generate colors that are similar?
The precise sizes of the potential energy jumps differ from metal to metal. As a result, the flame color of each metal will differ due to its unique spectral line pattern. The movement of the electrons in the metal ions contained in the compounds results in the hues of the flame.
The energy released by each electron when it returns to its initial condition determines the hue of the light that is produced.
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3. Could a molecule
contain only one atom?
What is the definition of a covalent bond?
1. A bond between two positive ions
2. A bond between a positive and a negative ion
3. A bond between two negative ions
4. A bond between two atoms
Answer:
4. A bond between two atomsExplanation:
A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms. These electrons are simultaneously attracted by the two atomic nuclei. A covalent bond forms when the difference between the electronegativities of two atoms is too small for an electron transfer to occur to form ions.
An arrow is moving at 35 m/s and travels for 5 seconds. How far does the arrow travel eters
Answer:
175 meters
Explanation:
Applying,
v = d/s............... Equation 1
Where v = velocity of the arrow, d = distance traveled by the arrow, t = time
make d the subject of the equation
d = vt............. Equation 2
From the question,
v = 35 m/s, t = 5 seconds.
Substitute these values into equation 2
d = (35×5)
d = 175 meters.
what is the molarity of a solution that contains 0.350 mol of Na2S in 1.30 L of solution
Answer: 0.27 M
Explanation:
molarity = (0.350)/(1.30) = 0.27 M
Using chemical equations, show how the triprotic acid h3po4 ionizes in water. Phases are optional.
The acid that contains three hydrogen ions are called triprotic acid.
The triprotic acid h3po4 ionizes in water:White solid pure anhydrous phosphoric acid melts into a viscous liquid at 42.35 degrees Celsius. Phosphoric acid, which contains three ion hydrogen atoms, acts as a triprotic acid in an aqueous solution. The hydrogen ions disappear one at a time.
H₃PO₄ (aq) ⇄ H⁺ (aq) + H₂PO₄⁻ (aq) Kₐ₁ = 7.5 × 10⁻³
H₂PO₄⁻ (aq) ⇄ H⁺ (aq) + H₂PO₄²⁻ (aq) Kₐ₂ = 6.2 × 10⁻³
HPO₄²⁻ (aq) ⇄ H⁺ (aq) + PO₄³⁻ (aq) Kₐ₃ = 7.5 × 10⁻³
The first dissociation constant of phosphoric acid indicates that it is not an especially potent acid. It is a weaker acid than hydrochloric acid and sulfuric acid, but stronger than acetic acid. The ease with which each subsequent dissociation stage happens decreases. As a result, H₂PO₄⁻ is a relatively weak acid but HPO₄²⁻ is an extremely weak acid.
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which electron pair geometry do you think is more stable for methane, tetrahedral or square planar? explain your choice.
Tetrahedral arrangement for electron pair geometry is more stable for methane when compared between tetrahedral and square planar.
In comparison, the square planar arrangement is not as stable as the tetrahedral arrangement. The reason behind this is as each C-H bond (molecular orbital) can be defined as a region of high electron (negative charge) density. It is just like repelling where each bond will repel the others and will move as far away from the other bonds as much as they could.
In a methane molecule, the carbon atom forms covalent bonds with four hydrogen atoms that are not similar to one another and there are no lone pairs on the carbon atom. Hence, the four hydrogen atoms are at the four corners of the tetrahedron, and carbon is at the center.
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The international space station (ISS) is 109 m long by 75 m wide and has a volume of about 932 m3 . Assuming air is about 70% nitrogen and 20% oxygen, how many molecules of each are approximately in the ISS knowing that the pressure is 1 atm and the temperature 293 K? Additionally, since the average person exhales 0.500 m3 of CO2 per day, which is about 1 kg, if the oxygen and CO2 scrubber system cuts outs, estimate how long do four astronauts have on the ISS before the air is no longer breathable and they pass out knowing humans need at least 80% of oxygen to keep vital organs healthy. (rO2 = 1.429 kg/m3 and rCO2 = 1.977 kg/m3 )
Approximately 2.22 x \(10^2^5\) molecules of nitrogen and 6.29 x \(10^2^4\)molecules of oxygen are present in the International Space Station (ISS). If the oxygen and CO2 scrubber system fails, four astronauts on the ISS have approximately 73 hours before the air becomes unbreathable and they risk losing consciousness.
The ISS has a volume of approximately 932\(m^3\). Given that air is approximately 70% nitrogen and 20% oxygen, we can calculate the number of molecules of each gas present in the ISS.To calculate the number of molecules, we need to use the ideal gas law equation, which states that PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature.First, we convert the volume of the ISS to liters: 932 \(m^3\) = 932,000 liters.
Next, we calculate the number of moles of each gas using the ideal gas law equation. The pressure is given as 1 atm, and the temperature is 293 K.
For nitrogen:
PV = nRT
(1 atm)(932,000 L) = n(0.0821 L·atm/(mol·K))(293 K)
n ≈ 2.93 x \(10^4\) moles
For oxygen:
PV = nRT
(1 atm)(932,000 L) = n(0.0821 L·atm/(mol·K))(293 K)
n ≈ 8.29 x \(10^3\) moles
Finally, we convert the number of moles to the number of molecules by multiplying by Avogadro's number (6.022 x \(10^2^3\) molecules/mol).
For nitrogen:
2.93 x \(10^4\) moles × 6.022 x \(10^2^3\) molecules/mol ≈ 2.22 x \(10^2^5\) molecules
For oxygen:
8.29 x \(10^3\) moles × 6.022 x \(10^2^3\) molecules/mol ≈ 6.29 x \(10^2^4\) molecules
Therefore, approximately 2.22 x \(10^2^5\) molecules of nitrogen and 6.29 x \(10^2^4\) molecules of oxygen are present in the ISS.
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What is the relationship between the density of the air molecules and the air pressure?
Please answer now