Lead absorption is decreased by the presence of ______ in the body. a) calcium and vitamin D b) calcium and iron c) iron and selenium
Answer: Correct option is B . calcium and iron decrease the absorption of lead in the body.
Explanation: calcium and iron decrease the absorption of lead in the body without affecting its solubility,probably by competing for shared absorptive receptors in the intestinal mucosa. The total body burden of lead does not affect lead absorption. Thus, lead does not have a feedback mechanism which limits absorption.
An inland area has little water or plant life.
What would the climate of this place likely be?
The inland area has a Continental climate.
Inland climates are typically more severe. Summers might be quite hot, and winters could be very frigid. Rainfall can be scarce.
In inland area the water bodies take long time to heat up and cool down, so they absorb all the heat during the spring and summer when the sun is at its greatest before slowly losing it throughout the fall and winter when the temperature starts to drop.
On the other hand, it warms up and cools down far more quickly on land, that's why the inland are more cooler.
Inland absorbs and releases heat energy more quickly than water, inland places typically experience higher temperature variations from day to night and from season to season, so that inland is hotter area also.
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a balloon initially has a volume of 0.400 L. the temperature is 20.C what will be the volume when he heats the balloon up to 250C
The balloon has a capacity of 0.7 L after being heated to 250°C.
We utilize the Charles' Law equation to determine the system's ultimate volume. According to this rule, the volume of a gas under constant pressure is precisely proportional to its temperature.
Mathematically,
V1/T1 = V2/T2
where,
V1 and T1 are the gas's starting volume and temperature.
V2 and T2 are the gas's ultimate volume and temperature.
We receive:
V1 = 0.4L
T1 = 20.C = (20 + 273)K = 293K
V2=?
T2 = 250.C = (250 + 273)K + 523)K
Using the values in the equation above, we obtain:
0.4/293 = V2/523
V2 = 0.7L.
As a result, the balloon has a capacity of 0.7 L after being heated to 250°C.
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A
Choose the correct symbol to
compare these numbers.
-4 [?] 0.589
A. <
B. >
C. =
Hello there!
Answer:
A. <
Explanation:
You should remember that all negative numbers are smaller then positive numbers. For example, -10 < 7 or -9479 < 1
-4 is a negative integer
0.598 is a positive number
So -4 < 0.598 (negative < positive)
Which of the following require(s) resonance structures to more accurately represent their electron arrangements
The correct representation about resonance structures is that The structure of the species cannot be correctly predicted by a single resonance structure and the only way resonance structures vary is in the way the electrons are arranged.
In valence bond theory, resonance is defined as a hybrid structure formed by combining a variety of contributing structure into a resonance hybrid. Because orbitals overlap, resonance happens. Pi bonds, created when two 2p orbitals overlap, are the building blocks of double bonds. These pi orbitals' electrons are delocalized since they will be dispersed across more than two atoms.
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What were the 3 missing elements in the periodic table?
The three missing elements in the periodic table are gallium, germanium and scandium.
Gallium, germanium, and scandium have been all unknown in 1871, however, Mendeleev left areas for every and expected their atomic loads and different chemical properties. Within 15 years, the “lacking” factors have been discovered, conforming to the simple traits Mendeleev had recorded. Scientists in Japan suppose they have eventually created the elusive detail 113, one of the lacking gadgets at the periodic table of factors. Element 113 is an atom with 113 protons in its nucleus — a kind of depend that should be created inner a laboratory as it isn't always located evidently on Earth.
The elements are gallium, germanium and scandium.
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When using a TSO-C129 or TSO-C196 GPS for navigation and instrument approaches, any required alternate airport must have
TSO-C129 and TSO-C196 refer to non-WAAS GPS systems. TSO-C146 refers to WAAS-enabled GPS systems. If non-WAAS GPS is used for navigation and instrument approaches, all required alternate airports must have non-GPS approved operational instrument approach procedures.
TSO-C129 - Airborne Auxiliary Navigation Sensor for Global Positioning System equipment with airborne extensions. TSO-C196 – Auxiliary airborne navigation sensor for GPS units with airborne augmentation.
TSO certification means minimum performance standards for certain materials, parts and equipment used in commercial aircraft. Authorization to manufacture materials, parts, or equipment in accordance with TSO standards is referred to as TSO authorization.
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Assume that you want to create 50.0 g aqueous solution that is 6.213% by mass sodium chloride. How many grams of sodium chloride should you start with
With 3.11 grams of sodium chloride we should start to make an aqueous solution of 50. 0 gm.
When water is used as a solvent then the solution is called the aqueous solution. Water is a good solvent which is naturally abundant and in chemistry, the word "solution" refers to the aqueous solution unless the solvent is specified. It is denoted by "aq".
Mass of aqueous solution = 50 gm
Mass percentage of sodium chloride = 6.213%
Let the mass of sodium chloride is N grams, then,
N = (50/100) × 6.213 gm
N = 0.5 × 6.213
N = 3.11 grams
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how does the hybridization of the sulfur atom change in the series SF2, SF4, SF6?
O sp, sp^3, sp^3 d^2 O sp^3, sp^3 d^2, sp^3 d^2 O sp^3, sp^3, sp^3 d^2 O sp, sp^3 d, sp^3 d^2 O sp^3, sp^3 d, sp^3 d^2
the hybridization of the sulfur atom change in the series SF2, SF4, SF6-Option 1 - sp, sp^3, sp^3 d^2 O sp^3, sp^3 d^2
The hybridization of the sulfur atom changes in the series SF2, SF4, SF6 as follows:
In SF2, the sulfur atom is in the sp hybridized state, meaning it has one s and one p orbital in its valence shell. This allows the sulfur to form a double bond with one fluorine atom.In SF4, the sulfur atom is sp3 hybridized, which means it has one s and three p orbitals in its valence shell. This allows the sulfur to form four single bonds with four fluorine atoms.In SF6, the sulfur atom is sp3d2 hybridized, which means it has one s, three p, and two d orbitals in its valence shell. This allows the sulfur to form six single bonds with six fluorine atoms.It is worth noting that the hybridization of the sulfur atom in SF6 is not very common and it is more likely the octahedral electron pair geometry of SF6 is achieved by the d orbitals of sulfur being empty and the sulfur atom being sp3 hybridized. In summary, the hybridization of sulfur in SF2 is sp, in SF4 is sp3, and in SF6 is sp3d2.
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How would you name this organic compound?
I found a couple ways to name it but I don't know which one's correct.
At one sewage treatment plant, bacteria cultures produce 1000 L of methane gas per day at 1.0 atm pressure. What volume tank (V2) would be needed to store one day's amount of gas at a pressure of 5.0 atm?
At a pressure of 5.0 atm, IS 200 L of gas would need to be stored in the volume tank (V2).
How to find the volume?The mass of a body can be calculated from its volume using density, and vice versa. The mass is equal to the volume multiplied by the density (M = Vd), whereas the volume is equal to the mass divided by the density (V = M/d). Use a laboratory scale to weigh the masses, or use the density formula D = m/V to convert the solvent volume to mass. Find your ultimate volume by multiplying the solute and solvent masses.Volume, which is measured in cubic units, is the area in three dimensions that matter occupies or that is encircled by a surface. Cubic metres (m3), a derived measure, are used as the SI unit of volume.To learn more about volume, refer to:
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A chemist has 200 mL of a 10% sucrose solution. If she adds x milliliters of a 40% sucrose solution, what is the percent concentration of the final mixture
The final concentration of the mixture depends on the value of x.
What is value?Value is the worth of something. It can refer to the monetary worth of an item or service, the usefulness of something, or the importance of an idea, belief, or experience. Value is a subjective concept and can vary from person to person. Generally, it is the positive attributes that an individual or group associates with something that determines its value. The economic concept of value is based on the idea that the value of a good or service is determined by its cost, supply, and demand.
The final concentration of the mixture is equal to:
(200 mL x 10%) + (x mL x 40%) / (200 mL + x mL)
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Which of the following elements when the central atom could exhibit sp 3 d 2 hybridization?
C, S, N, B
in the given following elements when the central atom could exhibit sp 3 d 2 hybridization , Sulphur(S) can exhibit the asked configuration.
Z=16 for Sulphur
Electronic configuration [tex]1S^{2} 2S^{2} 2P^{6} 3S^{2} 3P^{2} 3D^{0}4S^{0}[/tex] here we can clearly see that the energy difference between the 3p and 3d shell is very so sulphur can exhibit the asked configuration.
Z=6 for Carbon C - [tex]1S^{2} 2S^{2} 2P^{2}[/tex]
Z=7 for Nitrogen N- [tex]1S^{2} 2S^{2} 2P^{3}[/tex]
Z=5 for Boron B- [tex]1S^{2} 2S^{2} 2P^{1}[/tex]
Here we can clearly see that the atom is very small d the shell is not present in the configuration above also the energy difference between the shells will be high as they are close to the nucleus hence the asked configuration can not be exhibited.
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Select the correct answer. specific heat is the amount of heat required to raise the temperature of a material by 1°c per what unit?
a. volume
b. joule
c. mass
d. pressure
e. density
Specific heat is the amount of heat required to raise the temperature of a material by 1°c per mass
Specific heat is defined as the amount of heat energy required to elevate the temperature of a material by 1°C per unit mass.
It is a material's physical attribute. The joule per kelvin per kilogram (J/K/Kg) is the standard international measurement of heat capacity.
If a substance has a high specific heat, it simply implies that it will take a long time to heat up, but it will also take a long time to cool down once heated. Water has the highest specific heat value.
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A screw has _____ over the cylinder.
corkscrew-shaped ridge
What is a screw’s output?The screw’s applied force (output force) is always larger than the screw’s applied force (input force). As a result, a screw’s mechanical advantage is always larger than one.Screws are a type of basic machine. They have a thread, which is a corkscrew-shaped ridge wrapped around a cylinder. When driving in a screw, the head is particularly designed to allow a screwdriver or wrench to hold the screw.
Another sort of inclined plane is the screw. When an inclined plane wraps around a straight rod-like structure, a spirally grooved surface with a pointed end is generated. It serves to keep things together.
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What do your results tell you about the directing effects of the substituents on salicylamide?
The amide group in salicylamide is electron withdrawing, the hydroxyl group on the ring is a highly active, electron donating substituent. The hydroxyl group donates electrons, guided entry iodide to a para position.
What does the word "substituent" signify in chemistry?A substituent is an atom that are substituted for an atom here on parent chain of such a hydrocarbon in both chemistry and biochemistry constituting a moiety of the resulting new molecule.
Alkyl groups: are they substituents?Alkyl groups are substitutes created from alkanes. The names of alkyl groups and unbranched alkane chains are similar. Alkyl groups may branch as well. For instance, the butyl substituent has three constitutional isomers.
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Fill in the blank.
When using a graduated cylinder you must look at ________ of the liquid when taking readings.
When using a graduated cylinder you must look at Meniscus of the liquid when taking readings.
How to Read a Graduated Cylinder?The surface at the center of the meniscus, not the top of the ring of liquid clinging to the graduated cylinder's wall, must be read in order to read a graduated cylinder correctly. This "center" will be the meniscus's lowest point for the majority of liquids. The center of the meniscus will be the highest point of the liquid for a very small number of liquids, such as mercury. Your line of sight must be level with the meniscus's center of curvature in order to interpret it correctly.
Reading a graded cylinder is a matter of paying close attention to the details once the measurement interval has been established and the meniscus has been assessed. Read the numbered line below while keeping your eyes level with the meniscus's middle and looking straight down.
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32P has a half life of 14 days calculate the time taken for a given amount of 32P to decay to one - eight of its original activity
The time taken for a given amount of 32P to decay to one-eight of its original activity is 42 days.
A substance's half-life is the amount of time it takes for half of it to decompose. Given that each half-life period diminishes the activity by a factor of 2, if a given amount of a material with a half-life of 14 days decays to one-eighth of its initial activity, it must have gone through three half-life periods. Therefore, it would take 14 x 3 = 42 days for a given amount of 32P to decay to one-eighth of its initial activity.
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What is the name of the systematic approach that scientists use to understand the natural world?
a law
the scientific method
a hypothesis
a theory
It would be due to the scientific method
Hope this helps :)
The statement "atoms have a small, dense nucleus" is true. What evidence do scientists use to prove this statement as true?
Most alpha particles shot at gold foil go straight through, without any changes in their direction.
The particles ejected in Thomson's experiment bent away from the negatively charged plates, but toward positively charged plates.
A few alpha particles shot at gold foil bounce in the opposite direction
No matter which element Thomson put in a cathode ray tube, the smae negative particles wit the same properties (such as charge and mass) were ejectected.
In the gold foil experiment, alpha particles shot at gold foil bounced in the opposite direction from a gold foil which indicated atoms have a small, dense nucleus.
What is the gold foil experiment?Rutherford’s α-particle scattering or gold foil experiment changed our perception of the atomic structure of an atom. Rutherford bombarded beams of α-particles at thin gold foil and observed how the α-particles scattered from the gold foil.
Rutherford showed that the atom has the most empty space with the nucleus at the center and electrons rotating around the atomic nucleus. Highly charged α-particles passed straight undeflected through the foil. This will be the expected result if the plum pudding model of Thomson was correct.
A few charged alpha particles were deflected backward direction leading to the positive charge concentrated in a small space.
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What element has the largest radius?
Answer:
Francium
Hope this helps :)
The half-life of titanium-44 is 60.0 y. A sample of titanium contains 0.600 g of titanium-44. How much remains after 100.0 y
The amount of titanium-44 remaining will be 1/4 of the original amount, or 0.150 g.
What is amount?Amount is a quantity or magnitude of something, typically money. For example, a person may refer to the "amount of money" they have saved, the "amount of time" it takes to do something, or the "amount of food" they have purchased. Amount can also refer to the total number of something, such as the "amount of people" who have attended an event or the "amount of work" that needs to be done.
The half-life of titanium-44 is 60.0 y, meaning that after every 60.0 y, the amount of titanium-44 will be halved.
0.600 g - 0.150 g = 0.450 g
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Electronegativity Please Fill Out
The propensity of an atom of a certain chemical element to draw shared electrons when forming a chemical bond is known as electronegativity and is denoted by the symbol X.
What are Electronegativity?The atomic number and the separation of the valence electrons from the charged nucleus have an impact on an atom's electronegativity. An atom or a substituent group will draw electrons in greater amounts the higher the associated electronegativity. The sign and amplitude of a bond's chemical polarity, which characterizes a bond along the continuous scale from covalent to ionic bonding, can be quantitatively estimated using electronegativity. The inverse of electronegativity is electropositivity, which describes an element's propensity to accept valence electrons.
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How does the arrangement of atoms affect the classification of matter?
On the basis of arrangement of atoms, the matter is classified into three states: solid, liquid and gas.
In Chemistry, there are three fundamental states of matter based on the arrangement of molecules and atoms inside it.
Generally, solids have strict and rigid arrangement of atoms as they posses strong intermolecular forces and have high melting and boiling points. solids have fixed composition of atoms.
Similarly, liquids have loose arrangement of atoms and molecules keep moving randomly in a liquid. Liquids have low melting and boiling points as compared to solids. Gases have weakest intermolecular forces and atoms are arranged randomly in them. Also, their molecules keep moving in all directions.
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What is Ghez’s favorite star? Do you have a favorite star? Why or why not?
Andrea Ghez's favorite star is known as SO-2 and it is her favorite star because this star goes around the universe in a short period. I do not have a favorite star because I do not know a lot about stars.
Who is Andrea Ghez?Andrea Ghez is female astrophysicst who was born in the United States known for being one of the few women in the world who have gotten the Nobel Prize in Physics. During her life, Andrea has studied the center of the universe, black holes and the stars. Moreover, she was known for giving a TED talk in whiich she explained about stars and black holes.
What is Andrea's favorite start?In the TED talk given by Andrea Ghez she mentions her favorite star is the SO-2 as "it goes around in only 15 years".
What is my favorite star?I do not have a favorite star because I do not know a lot about stars, although I believe studying them is very interesting.
Note: This question is incomplete; here is the missin information:
TED Talk- Andrea Ghez
"Now, most astronomers have a favorite star, and mine today is a star that's labeled up there, SO-2. Absolutely my favorite star in the world. And that's because it goes around in only 15 years. And to give you a sense of how short that is, the sun takes 200 million years to go around the center of the galaxy"
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Find the mass in kilograms in 2.6 mol of C8H12 (which is called windowpane).
Considering the definition of molar mass, the mass in 2.6 moles of C₈H₁₂ is 0.2808 kg.
Definition of molar massThe molar mass of an atom or molecule is the mass of one mole of that particle expressed in grams.
The molar mass of a compound is the sum of the molar mass of the elements that form it multiplied by the number of times they appear in the compound.
Mass of 2.6 mol C₈H₁₂Being the molar mass of C₈H₁₂ 108 g/mole, you can apply the following rule of three: If by definition of molar mass 1 mole of the compound contains 108 grams, 2.6 moles of the compound contains how much mass?
mass= (2.6 moles× 108 grams)÷ 1 mole
mass= 280.8 grams= 0.2808 kg (being 1000 gr= 1 kg)
Finally, the mass is 0.2808 kg.
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A group of students is making paper airplanes. They think that the kind of paper and the design of the airplane may affect how far each paper airplane flies. The students first test if the kind of paper affects how far the airplane flies. They make several airplanes out of different kinds of paper, using the same design. Why is it important that all the airplanes have the same design? (SC. 6. N. 1. 1)
By using the same design, the students can learn about both the effect of the design and the effect of the paper.
By using the same design, the students can learn about the effect of the design.
If they do not use the same design, the students cannot learn about the effect of the paper.
It is NOT important for the airplanes to have the same design because the students are not testing the effect of the design
Students can learn about the impact of both the design and the paper by working with the same layout. Students can learn about causality in design by replicating it and seeing its effects firsthand. The pupils won't get the full benefit of the paper unless they all follow the same format. There is no need for uniformity in airplane design since pupils will not be comparing the performance of different planes.
For the first test, students conduct an experiment to evaluate whether or not different types of paper affect the airplane's range of flight. Therefore, in the first experiment, the distance the paper travels after being thrown is the dependent variable and the type of paper is the independent variable.
The airplane's design is kept constant so that any differences in flight distance can be attributed to variations in the paper used in the experiment.
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What is the concentration of the standard solution (in M) if 15 mL of a 0.2512 M Co(NO3)2 stock solution is added to a 50 mL volumetric flask and diluted to the mark
The concentration of the standard solution (in M) if 15 mL of a 0.2512 M Co(NO3)2 stock solution is added to a 50 mL volumetric flask and diluted to the mark is 0.07536M.
Given volume of Co(NO3)2 stock solution (V1) = 15mL =0.015L
Concentration of Co(NO3)2 stock solution is (M1) = 0.2512M
Volume of volumetric flask (V2) = 50mL = 0.050L
Concentration of standard solution = M2
The number of moles of solute divided by the number of liters of solution is the definition of molarity, a concentration unit in chemistry.
We know that M1V1 = M2V2. Such that,
0.2512 x 0.015 = M2 x 0.050
M2 = 0.07536M
Hence the required concentration of standard solution is 0.07536M
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What volume (in L) of nitrogen will be produced from the reaction of 6. 8 L of carbon monoxide?
2CO(g)+2NO(g)>N2(g)+2CO2(g)
The volume of nitrogen produced from the reaction of 6.8 L of carbon monoxide is 3.7 L
In order to determine the volume of nitrogen produced from the reaction of 6.8 L of carbon monoxide, we need to use the balanced equation for the reaction:
2CO(g) + 2NO(g) -> N2(g) + 2CO2(g)
From the equation, we can see that for every 2 moles of CO that react, 1 mole of N2 is produced. The volume of a gas is directly proportional to the number of moles of the gas present.
If the initial volume of CO is 6.8 L, we can assume that the number of moles of CO is
6.8 L / 24.45 L/mol = 0.278 mol.
Therefore, the number of moles of N2 produced would be
0.278 mol CO * (1 mol N2 / 2 mol CO) = 0.139 mol N2.
Finally, using the ideal gas law PV = nRT (where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature), we can calculate the volume of N2 produced:
V = nRT / P
V = 0.139 mol N2 * (8.314 J/mol*K) * (273 K) / (1 atm) = 3.7 L
So, the volume of nitrogen produced from the reaction of 6.8 L of carbon monoxide is 3.7 L.
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The potential danger involved with ingesting certain compounds is associated with their solubility in the body's aqueous environment. Which of the following would be most soluble in water ?
A.CH3CH2OH
B. CH3CH2CH2OH
C. CH3OCH2CH3
The solubility of a compound in water is determined by the type of chemical bonds present in the compound and the polarity of the molecule. Thus option B is the correct answer.
Compounds that are polar and have hydrogen bonding capability are more likely to be soluble in water.
In this case, Propanol (CH3CH2CH2OH) has a polar -OH group, which makes it able to form hydrogen bonds with water molecules, and therefore it would be more soluble in water than the other two compounds.
The other two compounds, CH3CH2OH (Ethanol) and CH3OCH2CH3 (Dimethyl ether), also have polar groups, but propanol has the most polar -OH group which is why it would be the most soluble in water.
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