Answer:
D. mid-ocean ridges
Explanation:
The location where seafloor spreading occurs is at mid-ocean ridges. Therefore option 4 is correct.
Mid-ocean ridges are underwater mountain ranges that extend through the Earth's oceans. They are formed by the tectonic plates diverging or moving apart from each other.
As the plates separate, magma rises from the mantle to fill the gap, creating new oceanic crust. The molten material solidifies to form new seafloor, which then moves away from the ridge in opposite directions.
Seafloor spreading is a key process in plate tectonics and the continuous renewal of the Earth's crust.
It leads to the expansion of the ocean basins and the formation of new crust, contributing to the overall movement and reshaping of the Earth's lithosphere.
Therefore, the correct answer is option 4: mid-ocean ridges.
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An investigator proposes a study to determine the clinical relevance of a new assay technique to measure minimal residual disease (MRD) in adolescent (age 14-16) cancer patients undergoing chemotherapy. The study requires that two additional bone marrow aspirates be performed during the course of chemotherapy. The subject's chemotherapy will not be altered based on the results of the assay technique measures. However, future patients with cancer would benefit from improved interventions based on study findings. The IRB determined that the activity was a minor increase over minimal risk. Which of the following statements best describes the IRB approval requirements for involving adolescent cancer patients in the research study?
Assent is not required, however, both parents must give permission for the inclusion of the adolescent child.
Assent of the child only is required.
Assent is not required, however, one parent must give permission for the inclusion of the adolescent in this study.
Assent of the child and permission of both parents are required.
The correct answer is D. Assent of the child and permission of both parents are required.
Explanation:
In any research study, it is required to ask for the assent of the participants, no matter if the risk is low, which is established by the Institutional Review Board or IRB that regulates ethics in research. This implies in the case presented, the assent of the child is necessary, especially because a medical procedure (additional bone marrow aspirates) will be performed, and this is related to risks.
Besides this, if the participant is a minor the permission of both parents or the legal is needed as the child might not have the maturity to decide whether to participate in the research study. Thus, the requirements are " Assent of the child and permission of both parents are required".
Describe how red shifts were used by cosmologists to determine that the universe was expanding. How
is this evidence for the big bang theory?
Explanation:
astronomers have discover that in general the future of a Galaxy is, the more redshift light is this mean that the further away the Galaxy are the faster they are moving this is similar to explosion where the bits moving fastest travel for furthest on the explosion redshift data provides evidence that the universe including space itself is expanding .
The coefficients in a chemical equation represent
the
Select one:
a. masses, in grams, of all reactants and
products,
O b. relative numbers of moles of reactants and
products,
c. number of atoms in each compound in a
reaction.
O d. number of valence electrons involved in the
reaction
Answer:
the answer is C
''number of atoms in each compound in a reaction.''
Explanation:
its a fact
The coefficients in the chemical equation represent relative numbers of moles of reactants and products. Therefore, option B is correct.
What is the chemical equation?A chemical equation can be explained as the representation of a chemical reaction in terms of chemical symbols. A chemical equation exhibits reactants participating, formed products in the reaction, and an arrow representing the direction of the chemical reaction.
The chemical equation in which the number of atoms of each element is equal on both sides of the chemical equation is known as a balanced chemical equation.
The law of conservation of matter needed to be followed while balancing a chemical equation.
The total mass of all elements on the reactant side should be equal to the total mass of all elements on the product side in a balanced chemical equation. The coefficients represent a number of moles of reactants and products.
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Easyyyyy plz ...................
Permanent hardness of water is caused by dissolved :-
A) CaCl
B) Ca(HCO3)2
C) Mg(HCO3)2
D) NaOH
Answer:
The answer is B
Explanation:
Answer:
Hello!
Your answer is B) Ca(HCO3)2!!
Explanation:
Hope this helps you!!
itsMATT04
:>
How many moles is 25g of ammonia (NH3) pls show steps and answere asap
Answer:
Explanation:
Note
I'm using rounded numbers. Every periodic table is different. Use yours to correct my approximations.
1 mole of NH3
N = 14
H = 1
3 H = 3
==========
1 mole = 17 grams
Number of moles in 25 grams
moles = given mass / molar mass
moles = ???
given mass = 25 grams
molar mass = 17 grams
n = 25/17
n = 1.47 moles
Volume occupied 3.52x10^32 moluchles
of Mathane (CH4)
1) At STP
Answer:
volume = 13097674418.528dm³
Explanation:
n = (3.52)*10^32/(6.02)*10^23)
n = (584717607.97)
n = volume /molar volume
molar volume at stp = 22.4dm³
volume= 584717607.97 x 22.4
volume = 13097674418.528dm³
Which of the following will only affect the reaction rate of gases?
A. Concentration
B. Catalyst
C. Pressure
D. Surface area
Answer:
D. Pressure
Explanation:
The rate of a reaction is defined as the speed at which the reactants are converted into products. Factors influencing the rate of a reaction are concentration, catalyst, temperature, surface area, and pressure, etc.
In case of the reaction rate of gases, pressure will only have its affect as pressure do not have any influence on solid and liquid.
While concentration, surface area and catalyst influence all reaction rates including solid, liquids and gases.
Hence, the correct option is (d) pressure.
You arrive at a crime scene and are told the body of the victim is at the bottom of a pool that is 10 m deep. You walk over to what you are told is a 12 m in diameter, cylindrical pool. From the outside of the pool, you can see that the body looks badly burnt. Your partner says, “It looks like our victim had been burned alive and tried to put out the fire by jumping in the pool. The victim likely drowned to death.” Something does not sit right with you though. If there was a fire, where did it start? There are no signs of combustion anywhere. You aren’t so sure and ask the crime scene investigator to run a sample of the pool water before letting anybody try to pull the body out. The CSI comes back to you and tells you that normal pool water pH is roughly around 7.2, but the pool pH is actually highly basic at a level of 13, with a concentration of hydroxide ions at 1.0 x 10-1 mol/L. It becomes obvious to you that the body wasn’t burned before going in to the pool, but AFTER, and there was no fire needed! You order the body to be removed from the pool, but the CSI interjects, “It would be too dangerous with a pH that high. I suggest you get some vinegar from the store and pour it in to the pool beforehand to drop the pH to 7. Draining the pool would take far too long and we need to examine the body as soon as possible.” She asks one of your constables to go to the store to purchase five 4L jugs of vinegar (pH = 2) to pour in the pool, as she states it is enough to bring the pH to a safe level of 7. It sounds like it could be enough vinegar based on your knowledge of acids and bases, but you want to double-check her estimate before sending your constable to the store. Verify whether or not she is correct using calculations. A diagram may help you with your calculations. Hint 1: 1m3 = 1000L Hint 2: Vcylinder = πr2h
Answer:
The vinegar is not enough to neutralize the pool.
Explanation:
The [OH⁻] in the pool is 1.0x10⁻¹mol / L. To know how many moles of OH⁻ are in the solution, you must calculate volume of the pool thus:
V(pool) = πr²h
Where radius is d/2 = 12m/2 = 6m
and h is deep of the pool = 10m
V(pool) = π(6m)²*10
V(pool) = 1131m³
As 1m³ = 1000L:
1131000L in the pool. And moles of OH⁻ are:
1.0x10⁻¹mol / L ₓ 1131000L = 131100 moles of OH⁻ are in the pool
The neutralization of OH⁻ with H⁺ is:
OH⁻ + H⁺ → H₂O
To neutralize the pool you must add 131100 moles of H⁺.
The H⁺ concentration in a vinegar pH = 2 is:
pH = -log [H⁺]
2 = -log [H⁺]
1x10⁻²M = [H⁺]
4L are just 4x10⁻² moles of [H⁺]. That means:
The vinegar is not enough to neutralize the pool.
Which action destroys topsoil?
Answer:
I think it erosion
Explanation:
Well erosion washes away top soil
example of nobel gas
Answer:
helium , krypton,xenon,radon, argon are noble gasses
Eczema is a type of skin disease that appears as rashes or swelling. Eczema causes skin irritation or itchiness. What type of tissue does eczema affect? A. nervous B. muscle C. epithelial D. connective
when humans burn fossil fuels, most of the the carbon quickly enters the atmosphere as carbon dioxide in the atmosphere in the process called
•transpiration
•combustion
•decomposition
•photosynthesis
please help !!!
How much of KCIO3, must be heated to produce as much O2, as required to burn 24 g of carbon?
Answer:
2KClO3 》》2KCl +3O2
C+ O2》》CO2
number of C moles
Required O2 moles (According to the mole ratio )
Relevant to the first equation, find the moles the KClO3, which is used to produce that amount of O2 moles
Now you can find the mass of KClO3
I mentioned the useful steps which can guide you to get the answer.
Explanation:
What period is Pb (lead) in?
O A. 14
O B. 6
O C. 4
O D. 5
The answer to the question is B
Answer:
[tex]\boxed{6}[/tex]
Explanation:
Lead Pb is an element in group 14 and period 6 in the periodic table.
what is a chemical bond? an attractive force between 2 molecules
Answer:
The chemical bond between 2 molecules is called an intermolecular force.
Answer:
Chemical Bond:
Attraction between two atoms results in the formation of a bond which is called a chemical bond.
Inter molecular Forces:
Attractive Force that in between 2 molecules is called Inter molecular Forces. (Inter : Between)
What is the correct formula for the Ksp of the reaction MgF2(s) – Mg2+ (aq) + 2F (aq)?
Ksp = [Mg2+][F]
Ksp =[Mg2+][F]2
Ksp = 2[Mg2+][F]
Ksp = [Mg2+][F]
Answer:
Ksp = [Mg₂⁺][F⁻]²
Explanation:
Ksp is the equilibrium constant for a solid dissolving in an aqueous solution. The equilibrium constant for a reaction is always products over reactants.
MgF₂ (s) ⇒ Mg₂⁺(aq) + 2F⁻(aq)
The equilibrium constant would be K = [Mg₂⁺][F⁻]². Since MgF₂ is solid, it is not included in the equilibrium expression.
Therefore, Ksp would be the same as the equilibrium constant.
Ksp = [Mg₂⁺][F⁻]²
Hope this helps.
Answer:
Ksp = [Mg2+]3 × [PO43-]2
Explanation:
edge 2021
Which commercial technology commonly uses plasmas? a radio a race car a television a microwave oven
Answer:
c
Explanation:
The commercial technology commonly uses plasma is a television. The correct option is c.
What is commercial technology?Commercial technology is any technology that is employed in the business world, including electric power, radio, television, phones, and other similar devices. These items are employed commercially in a variety of fields. An electrical gadget called television is used to watch entertainment.
Plasma is a substance found in televisions; these gas-filled pockets receive electricity to transform into plasma screens. The UV rays that these plasmas then emit create a picture as they pass through the phosphorus cells.
Thus, the correct option is c. a television, regarding a commercial technology that commonly uses plasmas.
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Give two reasons why mixing and heating sulphur powder and iron filings on a watch glass is chemical change
Answer:
When iron filings and sulphur powder are mixed and heated they undergo a chemical reaction and form ferrous sulphide (FeS). It is a new substance which has properties entirely different from Fe and S. Therefore, heating of mixture of iron and sulphur powder is a chemical change.
What evidence suggests that global climate change is causing the oceans to get warmer?
Answer:
A large point of evidence in this would be the rate of increase in how fast the polar ice caps are melting and the ocean is rising as a result. As the climate is getting warmer so are the oceans and this is causing the ice caps which are in the ocean.
Explanation:
In the reaction below green chlorine gas and brown
iodine chloride forms yellow iodine trichloride
Cl2 (g) + ICI () = IC13 (s)
If some chlorine is removed from the reaction, how will
it affect the color of the mixture?
A. It will become more green.
B. It will become more yellow.
C. It will become more brown.
OD. It will not change.
Answer:
The correct option is;
C. It will become more brown
Explanation:
Given that the reaction is as follows;
Cl₂(g) + ICl (g) ⇄ ICl₃
We have that the reaction and a decrease in the concentration of the reactants will favor the reverse reaction that is the decomposition of the yellow iodine trichloride and the formation of green chlorine gas and brown iodine chloride
Given that some green chlorine gas, which is part of the reactant, will be removed, the reverse reaction will be favored and initial concentration of the yellow iodine trichloride and the green chlorine gas will be reduced while the proportional concentration of the brown iodine chloride will increase and the mixture will become more brown.
Answer:
become more green
Explanation:
A substance is said to hygroscopic if it
absorbs
(a) Carbon (IV) oxide from the atmosphere
(b) from the surrounding
(c) Moisture from the atmosphere to form
a solution
(d) Moisture from the atmosphere without
dissolving in it.
Explain why all glassware must be dry and the solvent anhydrous during formation and reaction of a Grignard reaction. Explain why it is advisable to not clean your glassware with acetone before a Grignard reaction. Include balanced chemical equations in your answer. (4 pts)
Answer:
The Grignard reagent will be destroyed
Explanation:
The Grignard reaction is based on a carbanion production (RMgX). If water is present in the glassware, a reaction can take place with [tex]H_2O[/tex] and the desired product will not be produced. Because an "H" would be transferred from water to the Grignard reagent. (See figure 1)
If we have acetone in the glassware we will have a similar problem. The Grignard reagent would be destroyed and the desired product will not be produced. The Grignard reagent will attack the carbon in the carbonyl group and the carbanion would disappear. (See figure 2)
The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain pressures and temperatures. Which best describes this statement? This is a limitation of the kinetic-molecular theory. This is a postulate of the kinetic-molecular theory. This describes ideal gas behavior using the kinetic-molecular theory. This describes ideal gas behavior without the kinetic-molecular theory.
This is a limitation of the kinetic-molecular theory. Hence, option A is correct.
What are intermolecular forces?Strong intermolecular force is defined as the increase in viscosity of the liquid, increase in surface tension, decrease in vapour pressure, and an increase in the boiling point while weak intermolecular forces define as the decrease in viscosity, a decrease in surface tension, an increase in vapour pressure, and an increase in boiling point.
The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain pressures and temperatures which is a limitation of the kinetic-molecular theory.
Hence, option A is correct.
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The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain pressures and temperatures. This is a Limitation of the Kinetic Molecular Theory. Hence Opton (A) is correct.
What is Kinetic Molecular Theory of the Gases ?
According to the kinetic molecular theory, the average kinetic energy of gas particles is proportional to the absolute temperature of the gas.
The kinetic theory of gases is a simple, historically significant classical model of the thermodynamic behavior of gases, with which many principal concepts of thermodynamics were established.
Therefore, The closeness of particles of gas and their low speeds allow intermolecular forces to become important at certain pressures and temperatures. This is a Limitation of the Kinetic Molecular Theory. Hence Opton (A) is correct.
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Which is true of binary ionic compounds?
Select one:
a. They consist of only two atoms.
b. They consist of atoms of only two elements.
c. They contain two different anions.
d. They have bonds that share two valence electrons.
Answer:
Its a or d if im stupid my b
Explanation:
Binary ionic compounds consist of atoms of only two atoms and hence the term binary is given to them.
What are ionic compounds?Ionic compounds or electrovalent compounds are the type of compounds which are formed between two elements when there is an exchange of electrons which takes place between the atoms resulting in the formation of ions.
When the atom looses an electron it develops a positive charge and forms an ion called the cation while the other atom gains the electron and develops a negative charge and forms an ion called the anion.
As the two atoms are oppositely charged they attract each other which results in the formation of a bond called the ionic bond and the compound is called ionic compound.
When the compounds consist of atoms of only two elements the compound is called as a binary ionic compound.
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