Answer:
The meter, symbol m, is the SI unit of length
The second, symbol s, is the SI unit of time.
m - metre
s- second
The SI base units for length is meter and time is second.
What is SI units?SI unit stands for international system of units.
It is defined as a metric system that is used as a measurement standard expected globally.
There are basically seven SI based quantities
Thus, the SI base units for length is meter and time is second.
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6. A chemist needs 457.8 g of KMnO4 to make a solution. How many moles of KMnO4 is that?
7. How many moles of erythromycin (C37H67N013), a widely used antibiotic, are in 1.00 x 10°g of the
substance?
8. Cortisone (C21H2805) is a synthetic steroid that is used as an anti-inflammatory drug. How many moles of
cortisone are present in one 10.0 mg tablet?
Answer:
6) 2.9 moles of KMnO4
7) 1.36×10^-3 moles
8) 2.8×10^-5 moles
Explanation:
6) Number of moles is given as mass/molar mass
Mass of KMnO4= 457.8
Molar mass of KMnO4= 158.034 g/mol
Number of moles of KMnO4= 457.8 g/ 158.034 g/mol= 2.9 moles of KMnO4
7) mass of erythromycin= 1.00×10^0 g
Molar mass of erythromycin= 733.93 g/mol
Number of moles of erthromycin= 1.00×10^0 g/ 733.93 g/mol = 1.36×10^-3 moles
8) mass of cortisone= 10.0 mg= 10×10^-3g
Molar mass of cortisone= 360.45 g/mol
Number of moles of cortisone= mass/molar mass= 10×10^-3 g/ 360.45 g/mol = 2.8×10^-5 moles
The force between two objects, each of charge -Q is measured as +F when the objects are separated a distance 2d apart. If the charge on only one object is tripled, determine the new force between them:
Answer:
Fnew = k (-3Q *(-Q)) / (2d)²
Fnew = k * 3Q² /4d²
Explanation:
This is Coulomb's law
F = k (q₁*q₂)/r²
F - electric force
k - Coulomb constant
q₁, q₂ - charges
r - distance of charges
Starting situation : q₁ = -Q, q₂= -Q , r =2d
F = k (-Q*(-Q)) / (2d)²
F = k *Q² /4d²
NEW FORCE : q₁ = -3Q, q₂= -Q, r =2d
Fnew = k (-3Q *(-Q)) / (2d)²
Fnew = k * 3Q² /4d²
Iron nails are often coated with paint or zinc to reduce rusting. Iron usually rust when getting in contact with which of the following?
CO2
H2
N2
O2
Iron rusts due to oxidation, which is basically just iron reacting with oxygen to produce iron oxide, which is called rust.
Please help me with all 3! Thank You!!
The bus company that your school uses is thinking about changing the material that
makes their current fleet of buses because the buses are running into problems with
corrosion, the reaction of metals with oxygen present in air to form metal oxides that
are not structurally sound and are visually unappealing. In addition, the current
construction material is difficult to shape and is not visually attractive. The bus
company has asked your teacher to recommend an alternative material that could be
used to manufacture the next round of buses needed for your school and other schools
in the district. In addition to meeting certain chemical and physical requirements, the
material recommended must also be affordable.
Answer:
):
Explanation:
What would happen to a weak acid dissociation equilibrium if more reactants
were added
A. The concentration of reactants would increase.
B. Equilibrium concentrations would not change.
C. The concentration of products would increase.
D. The equilibrium constant would change.
K is unchanged. The equilibrium constant wouldn't change. it is based on le chateliers principle.
Equilibrium concentrations would not change. Hence, option B is correct.
What is chemical equilibrium?Chemical equilibrium is a reversible chemical reaction in which no net change in the amounts of reactants and products occurs.
Step-by-step explanation:
The general equation for the dissociation of a weak base is
B + H₂O ⇌ BH⁺ + OH⁻
According to the principle, when stress is applied to a system at equilibrium, the system will respond in a way that tends to relieve the stress.
If you apply stress by adding more BH⁺ or OH⁻, the system will respond by moving in a direction that gets rid of the added ions.
The position of equilibrium will shift to the left, forming more of the undissociated base.
Hence, equilibrium concentrations would not change.
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Relate dark matter to the development of the universe after the Big Bang. In 3-5 sentences, speculate on how the development of the universe would have been different if there had been no dark matter. In your answer, use the term structures.
Please answer
Answer:
Dark matter makes up 85% of the mass of the universe. Dark matter is not directly observable because it doesn't interact with any electromagnetic wave. In the development of the universe, without dark matter, the universe will not function, move or rotate as it does now (this speculation led to the quest to find the anomaly of mass and energy in the known universe, eventually leading to the idealization of dark matter) and will not have enough gravitational force to hold it together. After the big bang, the presence of dark matter and energy ensured that the newly formed universe didn't just float away, rather, it provided enough gravitational force to hold the universe while still allowing it to expand sufficiently.
The development of the universe would have been different without the universe in the sense that the young universe won't have enough mass to hold it together, and the universe would have simply floated apart. The behavior of the universe would have been different from what we observe now, and some physical laws that applies now will not apply to the universe.
Without dark matter, the universe will neither move, rotate, or be able to function.
It should be noted that dark matter makes up about 85% of the mass of the universe. Dark matter does not interact with an electromagnetic wave.
Without dark matter, the universe will neither move, rotate, or be able to function. After the big bang, the dark matter was vital in providing the gravitational force to hold the universe.
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At a nuclear power plant, workers wear protective clothing and dosimeters to
measure their exposure to radiation, the nuclear fuel is held in an airtight steel
vessel, and the reactor is covered with reinforced concrete. All of these
efforts work to:
A. cool the nuclear fuel.
B. contain the radiation.
C. preserve the nuclear fuel to allow time for half-life decay.
D. absorb the free neutrons.
At a nuclear power plant, workers wear protective clothing and dosimeters to measure their exposure to radiation ,the nuclear fuel is held in an airtight vessel, and the reactor is covered with reinforced concrete to contain the radiation. that is in Option B.
What is the significance of the nuclear power plant?Nuclear power plants are plants that are specially established in various countries to test nuclear weapons, with various regulations related to them, and there are many types of safety measures taken to prevent any type of harm to the person or scientists. Different nuclear weapons are tested here that give the country its power to defend itself.
Hence, at a nuclear power plant, workers wear protective clothing and dosimeters to measure their exposure to radiation ,the nuclear fuel is held in an airtight vessel, and the reactor is covered with reinforced concrete to contain the radiation. that is in Option B.
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Which is the anode (oxidation) and cathode (reduction)?
2H+ + 2e- --> H2(g)
2Cl- --> Cl2(g) + 2e-
Answer:
2H+ + 2e - ---> H2(g) is the cathode
2Cl - ---> Cl2(g) + 2e - is the anode
Explanation:
Hydrogen ion has gained two electrons, making it undergo reduction. While chlorine has lose two electrons, hence undergoing oxidation.
which has a higher boiling point? please help!
What is the boiling point of
gold
1064.43°C
2970°C
1313°C
3266°C
Answer:
The melting point of Gold is 1064.43 degrees celsius and the boiling point is 2807 degrees celsius.
Answer:
2970 C
Explanation:
It melts at 5387 F and 2970 C
Place the atomic theories in the order in which they were published.
Answer:
Solid sphere model.Plum pudding model.Nuclear model.Planetary model.Quantum model.Explanation:
John Dalton proposed, the solid sphere model, he stated that atoms were indivisible and that every atom of a certain element had specific characteristics.J.J Thomson proposed, the plum pudding model, he stated that atoms were made of electrons that floated around a positively charged cloud.Ernest Rutherford proposed, the nuclear model, he stated that the atom was made of a central positive charge that was surrounded by electrons, it was not a cloud or sphere of positive energy, this, was concentrated in the nucleus and space where the electrons were was empty space.Niels Bohr proposed, the planetary model, he stated that electrons were around the positive nucleus but in orbits with different levels of energy.Lastly, Erwin Schrödinger proposed, the quantum model, this states that electrons move around a positive nucleus, but in waves, they are dispersed around the nucleus in orbitals.Which is the anode and which is the cathode?
2H+ + 2e- ➖> H2 (g)
2I- ➖> I2 + 2e-
Answer:
2l- ---> l2 + 2e- is the anode
2H+ + 2e- ---> H2(g) is the cathode
Explanation:
Oxidation occurs when a metal loses two or more electrons in a redox chemical reaction and reduction is when it gains. Thus, oxidation is the anode and reduction is the cathode.
What is the difference between a strong base and a weak base?
O A. A strong base is always more concentrated than a weak base.
B. A strong base produces more ions in solution than a weak base.
O C. A strong base has a lower Ky than a weak base.
O D. A strong base is not as conductive as a weak base
Answer: the answer is B!
Explanation: took the quiz
Bases produce salts by reacting with acidic solutions. The strong base releases more ions in the aqueous solution compared to the weak base. Thus, option B is correct.
What are a strong base and a weak base?Strong bases are substances that dissociate completely in the solution to produce hydroxide ions. They are completely ionizable and yield more ions than weak bases. The relative basic strength depends on the formation of the ions.
On the other hand, the weak bases are not capable of dissociating completely and rather partially dissociate to produce hydroxide ions. They yield less number of ions and have relatively less strength.
Sodium hydroxide, potassium hydroxide, cesium hydroxide, etc, are strong bases while, ammonium hydroxide, ammonia, aluminum hydroxide, etc., are weak bases.
Therefore, the strong and weak bases differ on dissociation.
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Which mammal below lays tough leathery eggs? A) bear (placental) B) duck-billed platypus (monotreme) C) kangaroo (marsupial) D) bat (placental)
Answer:
the answer to your question is B) Monotreme.
Explanation:
most mammals do not lay eggs, they give birth. But, monotreme mammals including the duck-billed platypus do in fact lay shelled eggs.
PLEASE HELP!
A neighbour says that she is going to get rid of a large pile of combustible rubbish by burning it. Describe whether the rubbish has really disappeared after burning. Explain any scientific principle that supports your answer.
Answer:
yes, the trash did disappear when she burned it however it releases smoke into the air (and harmful chemicals)
Explanation:
burning trash doesn’t only allow the waste to go down, it will also produce heat and electricity-while producing less greenhouse gas pollution than burning fossil fuels. However trash fires in burning barrels can smolder and, as a result, produce more harmful chemicals in smoke. Harmful contaminants can also be found in dirt. in conclusion, yes trash does disappear when burned but realeases many harmful chemicals.
hope this helped!
how many atoms of potassium and how
many atoms of oxygen must be present in the
compound's formula?
Energy 1:Question 8
What is a difference between a 90°C cup of water and a 40°C cup of
water?
Please hurry!!!
Answer:
50 C?
Explanation:
90 - 40 = 50 So 50 degrees celsius is your answer
Answer: pretty sure its C
Explanation:
Why is a Container important to the sustainability of your hydroponic system?
What are all the ways that a substance can change phase?
Answer:
There is 6 ways substance can change phase. They are melting, freezing, evaporating, condensing, sublimination, and deposition.
Hope this helped
Explanation:
What can you determine about an element if you only know its group number
on the periodic table?
A. The number of valance electrons
B. The total number of protons and neutrons
C. The number of protons
ОО
D. The total number of electrons
Answer:
the number of protons
Explanation:
the
NEED URGENT HELP WITH SCIENCE HOMEWORK. TRIED MY BEST TO FIGURE OUT BUT COULDNT. I WILL MARK YOU BRAINLIEST!!
Morains are
depositional material covered up when a glacier forms
deposition material exposed after a glacier retreats
depositional material on top of a glacier
Which of the following is a feature of old glacial areas?
Limestone pavement
Deserts
Fjords
Which of the following is required for karst topography?
limestone rock is exposed to the surface
precipitation is adequate for the necessary chemical reactions to occur
both of the above
Which of the following causes most coastal erosion?
Wind
Waves
Biological activity
Which of the following statements is false about constructive waves on coastal shorelines?
Constructive waves carry sand to the shoreline
Compared waves deposit sand on the shoreline
Constructive waves are the major contributor to beach erosion
The fetch is the water that washes up on a shore after the breaking of a wave.
True
False
Wave refraction, the bending of waves as they approach an island, is the process responsible for the formation of bays.
True
False
The subtropical zones are ________ because they are influenced by dry descending air.
dry deserts
warm tropics
cold tundra
In humid climates, dense vegetation discourages wind erosion.
True
False
Answer:
1. a
2. c
3. b
4. d
5. True
6. True
7. Cold Tundra
8. False
Explanation:
These are the answers. I had the same questions on my science quiz.
If black fur is dominant in rabbits, is it ever possible for two black fur rabbits to produce a white fur offspring?
Answer:
No
Explanation:
It is not possible because the Black fur is the dominant gene and White fur is not therefor if both rabbits have black fur it is impossible for the offspring of the rabbits to have white fur.
Aluminium would have similar properties to which of the following chemical elements?
Germanium
Gallium
Iron
Copper
Answer:
Gallium
Explanation:
Elements found in the same group of the periodic table, possess similar chemical properties. Aluminium and Gallium are found in Group 13 of the periodic table,hence, have similar properties.
When wood is burned is this a physical or chemical change ?
Answer:
physical
Explanation:
no chemical reaction is occurring
How many liters of H2 at STP are required to react with 2.3 g of Fe3O4 to give FeO and H2O?
Answer:
0.22L of H2
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
Fe3O4 + H2 —> 3FeO + H2O
Next, we shall determine the number of mole present in 2.3g of Fe3O4. This is illustrated below:
Molar mass of Fe3O4 = (56x3) + (16x4) = 232g/mol
Mass of Fe3O4 = 2.3g
Mole of Fe3O4 =..?
Mole = Mass/Molar Mass
Mole of Fe3O4 = 2.3/232 = 9.91x10^-3 mole.
Next, we shall determine the number of mole H2 needed for the reaction. This is illustrated below :
From the balanced equation above,
1 mole of Fe3O4 reacted with 1 mole of H2.
Therefore, 9.91x10^-3 mole of Fe2O3 will also react with 9.91x10^-3 mole of H2.
Finally, we can obtain the volume of H2 required for the reaction as follow:
1 mole of a gas occupy 22.4L at stp.
Therefore, 9.91x10^-3 mole of H2 will occupy = 9.91x10^-3 x 22.4 = 0.22L
Therefore, 0.22L of H2 is required for the reaction.
Help please!
Balance the following skeleton equation as illustrated below.
Answer:
The answer is H2(g) + Cl2(g) → 2HCl(g).
If the needle deflects East, what would happen if you reversed the current?
Answer:
the north and south poles will exchange places.
Explanation:
The intensity of the magnetic field produced around the conductor depends on the volume of current. Unless the position of the current is inverted, the compass needle travels in the same position, since the polarity of the magnetic field is inverted.
hope I helped!
Which of the following phase changes occur at point B on the phase diagram shown below?
A) boiling
B) melting
C)sublimation
D) condensation
Answer:
C. sublimation
Option C is correct answer
All of the given phase changes occur at point B on the phase diagram shown in question because point B is the triplet point.
What is triplet point?The point at which all three phases meet and exist in the phase diagram is called Triplet point. So all six phase changes occur at that point like sublimation, boiling, melting, condensation, deposition and freezing.
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CHEM PLZ HELP Explain the energy changes that occur when the following reaction happens:
H2 + Cl2 → 2HCl
Select all that are correct.
Question 9 options:
Energy is absorbed when the HCl bonds form.
Energy is needed to break the bonds of H-H in H2 and Cl-Cl in Cl2
Energy is released when the bonds of H-H in H2 and Cl-Cl in Cl2 break.
Energy is released when the H-Cl bonds form.
No energy changes occur when this reaction happens.
Answer:
Energy is needed to break the bonds of H-H in H2 and Cl-Cl in Cl2
Energy is released when the H-Cl bonds form.
Explanation:
During a chemical reaction, energy is needed to break the bonds between reactants in order for reactants to recombine with each other to form products.
According to the collision theory, chemical reactions occur when reactant particles of appropriate activation energy collide with each other to form the products. This implies that energy must be absorbed in order to break Cl-Cl and H-H bonds in the reactants so that they can collide to form HCl. As the new bond is formed in the product, the excess energy absorbed by the reactants is given off.