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.Mr. Holmes sure likes to play with Legos now that he is staying home these days. He was thinking that nuclear reactions were just like playing with lego pieces. Here are his three ideas why legos are like nuclear reactions.
1. If he builds a project that is too big, it will fall apart on its own because the connections are not strong enough to hold the pieces together.
2. Putting smaller lego pieces together to create bigger objects provides Mr. Holmes lots and lots of energy. He could keep doing this for a very long time.
3. While it causes a mess, Mr. Holmes gains energy by taking large objects and smashing them into smaller objects. While this is fun, it only lasts a limited time, because the large objects to smash are pretty scarce.
Which of the following reactions nuclear reactions is Mr. Holmes thinking of in this scenario?
Question 21 options:
1 – Fission 2 – Fusion 3-Radioactive Decay
1 – Radioactive Decay 2 – Fission 3 – Fusion
1 – Fusion 2 – Radioactive Decay 3- Fission
1 – Radioactive Decay 2- Fusion 3 – Fission
Answer:
1 – Fission 2 – Fusion 3-Radioactive Decay
Explanation:
The first scenario described in (1) is a fission reaction. Recall that in a nuclear fission, large nuclei disintegrate spontaneously. This is because the nuclei has a large number of nucleons hence a greater repulsion between them. This causes the large nuclides to be unstable and disintegrate spontaneously, releasing neutrons in the process.
The second scenario is typical of nuclear fusion, two light nuclei combine together to form a lager nucleus with a tremendous release of energy. This is typified in the fusion of hydrogen isotopes to form helium.
The third scenario depicts radioactive decay, radioactive decay often involves the spontaneous disintegration of a radioactive nucleus to form daughter nuclei with the emission of beta, gamma or alpha rays.
Why do we need energy and list three type of energy
Answer:
Energy is something very important to people. It helps to light our homes, dry our clothes, and even cook our food. If we didn't have energy I don't know where we'd be. Three types of energy are: Solar Energy, Wind Energy, and Hydro Energy.
Answer:
We need energy because without it we won't be the same. Infact, we won't be alive today. We use energy for everyday things and well, for everything.
Explanation:
3 types of energys are Electric, Atomic and Mechanical.
WOW thank you for 42 points c:
ASAPPP. Describe how you could determine the specific heat of a sample of a solid substance. You may
assume that the substance does not react with water. In your answer, make sure to include a
description of what equipment you would use and how you would interpret the data you collected.
Answer:
I would use calorimetric to determine the specific heat and I would measure the mass of a sample
Explanation:
I would use calorimetry to determine the specific heat.
I would measure the mass of a sample of the substance.
I would heat the substance to a known temperature.
I would place the heated substance into a coffee-cup calorimeter containing a known mass of water with a known initial temperature.
I would wait for the temperature to equilibrate, then calculate temperature change.
I would use the temperature change of water to determine the amount of energy absorbed.
I would use the amount of energy lost by substance, mass, and temperature change to calculate specific heat.
Answer:
I would use calorimetry to determine the specific heat. Then I would measure the mass of a sample of the substance. After that I would heat the substance to a known temperature. I would place the heated substance into a coffee-cup calorimeter containing a known mass of water with a known initial temperature. The coffee cup would be Styrofoam because it keeps the temperatures on the outside from getting on the inside and I would wait for the temperature to equilibrium, then I would calculate the temperature change. I would use the temperature change of water to determine the amount of energy absorbed. lastly, I would use the amount of energy lost by substance, mass, and temperature change to calculate specific heat.
Explanation:
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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Plz hurry!!
When an electron moves from a lower to a higher energy level, the electron
A absorbs a continuously variable amount of energy
B always doubles its energy
C moves closer to the nucleus
D absorbs a quantum of energy
Answer:
Absorbs a quantum of energy
Explanation:
An ultraviolet ray of light has a wavelength of 1.5x10^-8 m. What is the ray's
frequency?
Answer:
2 E16 Hz or 2 * 10^16 Hz
Explanation:
The formula to determine frequency is f = c / λ.
f = frequency
c = speed of light
λ = wavelength
f = 3E8 / 1.5E-8
f = 2E16
This makes sense because UV light exists roughly
between 8E14 Hz and 3E16 Hz ----- 2E16 Hz falls in that range
The ray frequency is 2 *[tex]10^{16}[/tex] Hz
How to find Ray's frequency?The formula to determine frequency is f = c / λ.
f = frequency
c = speed of light
λ = wavelength
f = 3*[tex]10^{8}[/tex] / 1.[tex]5^{-8}[/tex]
f = 2*[tex]10^{16}[/tex]
Frequency is the number of occurrences of a repeating event per unit of time.
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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.
Kick a ball and it'll fly up into the air before falling back down to the ground. A force is a pushing or pulling action that can make things move, change direction, or change shape. Which of these is NOT a force acting on the football?
A) The force of gravity is pulling the ball back to the ground.
B) Kicking the ball applies a force that sends it into the air.
C)The force of gravity sends the ball sailing through the goal post.
D)As the ball rolls across the ground, the force of friction brings it to rest.
Answer:
c
Explanation:
i think this is the answer hope this helps
Look at the reaction below.
H2SO4(aq) + Mg(s)->MgSO4(aq) + H2(g)
Which substance is the acid in the reaction?
Mg(s)
H2(g)
MgSO4(aq)
H2SO4(aq)
Mark this and return
Answer:
H2SO4
Explanation:
H2SO4 is actually one of the strongest acids, coming to pH value very close to 1 . Acids transfer their hydrogen ions to other substances , such as water , and usually have hydrogen their formula . In this case , H2SO4 has hydrogen in its formula and is acid in the case .
Hope it helps you !!
Answer:
person above me is right :)
Explanation:
Which of the following is a possible definition of a base?
Select one:
a. A substance that increases the concentration of hydronium ions in a solution
b. A compound that is a hydrogen ion acceptor in an acid-base reaction
c. A substance that is an electron pair acceptor in a reaction
d. A compound that gives off hydrogen ions in a reaction or solution
Answer:
The correct answer is B. A compound that is a hydrogen ion acceptor in an acid-base reaction
What is the name of this molecule? A. cis-2-pentene B. 2-pentyne C. 2-methylpentane D. Pentane
Answer:
Im sure its 2-Pentyne
So B. 2-Pentyne is the right answer
The name of the molecule which is present in the given image is 2-Pentyne as double bond is present at 2nd position.
What will bond show in structure?Presence of any bond in any structure of any molecule will tells about the unsaturation.
Double bonded molecule is known as alkene and triple bonded molecule is known as alkyne.
In the given diagram total 5 carbon atoms are present, two at the sides of triple bond, two at the corners and one at the bent position and triple bond is present at the middle of 2nd and 3rd carbon atoms. So, the name of the given compound is 2 pentyne.
Hence name of the compound is 2 pentyne.
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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
Which type of resource uses flowing water to create electrical energy?
O Hydropower
O Natural gas
O Nuclear energy
O Solar power
Answer: Hydropower
Explanation: Hydropower is using water to power machinery or make electricity.It uses water as a fuel, water constantly moves through a vast global cycle, evaporating from lakes and oceans, forming clouds, precipitating as rain or snow, then flowing back down to the ocean.
NEED HELP!
Please refer to the picture for the question!
Answer: i think the best bet i can give you is Option C (2:3)
Explanation: i apologize i haven't done chem in 2 years
but however to put it in retrospect the finished equation is 2(AL)^+3 3(O)^-2
which has a higher boiling point? please help!
What structural adaptation of the A. cristatus lizard helps them in the water?
A: webbed feet for swimming
B: strong claws for climbing
C: serpentine movement of tail
D: sunning on rocks
Answer:
Well, The best answer will be is A. Webbed feet for swimming.
Good Luck!~
[tex]^{Brazts[/tex]
Answer:
webed feet for swimming
Explanation:
i took k-12 test
When a 1.0 M KCl solution is electrolyzed using silver electrodes, a precipitate forms at the anode. Explain this result please.
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
NutraSweet is 57.14% C, 6.16% H, 9.52% N, and 27.18% O.
What is the empirical formula of NutraSweet and
what is the molecular formula. (The molar mass of NutraSweet is 294.30 g/mol)
Elements. C. H. N. O
% Composition 57.14 6.16 9.52. 27.18
Molar mass. 12 1. 14. 16
Moles. 4.76. 6.16. 0.68. 1.70
mole ratio 7. 9. 1. 2.5
Multiply by 2
to make it a whole. 7*2. 9*2. 1*2 2.5*2
number
= 14. 18. 2. 5
EMF C14H18N2O5
EMF(n) = MF
12 + 1 + 14 + 16(n) = 294.30
43n = 294.30
n = 7 (to 1 decimal place)
there MF = C14H18N2O5(7)
= C98H126N4O35
The empirical formula of NutraSweet is C14H18N2O5 while the molecular formula is C14H18N2O5
HOW TO CALCULATE EMPIRICAL FORMULA:
The empirical formula of a compound can be calculated as follows:The following are the composition of Nutrasweet:57.14% C = 57.14g
6.16% H = 6.16g
9.52% N = 9.52g
27.18% O = 27.18g
Next, we divide each element's mass value by its molar mass to get number of moles:C = 57.14g ÷ 12 = 4.762 mol
H = 6.16g ÷ 1 = 6.16 mol
N = 9.52g ÷ 14 = 0.68 mol
O = 27.18g ÷ 16 = 1.699 mol
Next, divide each mole value by the smallest (0.68 mol)C = 4.762 ÷ 0.68 = 7.00
H = 6.16 ÷ 0.68 = 9.06
N = 0.68 ÷ 0.68 = 1
O = 1.699 ÷ 0.68 = 2.49
We multiply each value by 2 to get a whole number ratio. That is;C = 14
H = 18
N = 2
0 = 5
The empirical formula of Nutrasweet is therefore; C14H18N2O5The molecular formula can be calculated thus;(C14H18N2O5)n = 294.30
12(14) + 1(18) + 14(2) + 16(5) = 294.3
(168 + 18 + 28 + 80) = 294.3
294n = 294.3
n = 294.3/294
n = 1.000
This means that the molecular formula of Nutrasweet is C14H18N2O5.
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Wht are the definitions of these words.
Communication systems
Import dependency
Opencast mine
Hinterland
Carbon capture
Answer:
this Is your communication system and Import dependency
Why is a Container important to the sustainability of your hydroponic system?
Which equation represents a reduction half-reaction?
A)
Fe Fe3+ + 3e–
B)
Fe + 3e– Fe3+
C)
Fe3+ Fe + 3e–
D)
Fe3+ + 3e– Fe
Answer:
Fe3+ + 3e– --------> Fe
Explanation:
Reduction refers to a gain of electrons. A specie is said to be reduced when it gains electrons or when it experiences a decrease in oxidation number. The both sentences above can be clearly seen when inspecting a reduction half equation.
Consider the redox reaction half equation;
Fe3+ + 3e– ------>Fe
We can see that Fe^3+ accepted three electrons, the oxidation number of iron thereby decreased from +3 to zero from left to right. This implies that the Fe^3+ was actually reduced according to the equation shown.
Equation which represents a reduction half - reaction is Fe³⁺ + 3e⁻ → Fe.
What is reduction?Reduction is a process in which addition of hydrogen or electron or removal of oxygen takes place.
From the given reaction, only last reaction represents a reduction half -reaction as:
Fe³⁺ + 3e⁻ → Fe
In this reaction on the left side iron is present in +3 oxidation state and due to addition of 3 electrons it converts into Fe atom which is in 0 oxidation state on the right side. So, due to addition of electrons reduction takes place.
Hence, Fe³⁺ + 3e⁻ → Fe represents a reduction half-reaction.
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Consider the following unbalanced equation. How many Liters of bromine are needed to produce 12 moles of Aluminum bromide? The density of bromine is 3.1 g/mL.
Al (s) + Br2 (l)= AlBr3 (s)
Answer:
0.92787 liters of bromine are needed to produce 12 moles of aluminum bromide.
Explanation:
You have the following balanced equation:
2 Al (s) + 3 Br₂ (l) ⇒ 2 AlBr₃ (s)
First of all, the following rule of three should be applied to know the amount of moles of bromine needed: if 2 moles of aluminum bromide are produced by stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction) for 3 mole of bromine, 12 moles of aluminum bromide with how many moles of bromine are produced?
[tex]moles of bromine=\frac{12 moles of aluminum bromide*3 mole of bromine}{2 mole of aluminum bromide}[/tex]
moles of bromine= 18
Being the molar mass of the bromine Br₂ 159.8 g/mol then the mass of 18 moles of Br₂ is:
18 moles* 159.8 g/mol= 2,876.4 grams
Density is a property that indicates the amount of mass per unit volume. Then the following rule of three applies: if by the definition of density 3.1 grams of bromine are present in 1 mL, 2,876.4 grams of bromine are present in how much volume is it?
[tex]volume=\frac{2,876.4 grams*1mL}{3.1 grams}[/tex]
volume= 927.87 mL
Being 1,000 mL= 1 L, then 927.87 mL= 0.92787 L
0.92787 liters of bromine are needed to produce 12 moles of aluminum bromide.
Answer:
[tex]V=929mL[/tex]
Explanation:
Hello,
In this case, the balanced chemical reaction is:
[tex]2Al (s) + 3Br_2 (l)\rightarrow 2AlBr_3 (s)[/tex]
In such a way, we use the 2:3 molar ratio between aluminum bromide and bromine and its atomic mass which is 160 g/mol to find the grams of bromine that are produced:
[tex]m_{Br_2}=12molAlBr_3*\frac{3molBr_2}{2molAlBr_3} *\frac{160gBr_2}{1molBr_2} =2880gBr_2[/tex]
Then we compute the volume:
[tex]V=\frac{m}{\rho}=\frac{2880gBr_2}{3.1g/mL}\\ \\V=929mL[/tex]
Regards.
What will happen is 95g of NH3 is placed in 65g of water at 65 degrees Celsius?
Answer:
i think wait if its cold idk but hot it will burn u
Explanation:
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:
which best describes a difference between prokaryotic and eukaryotic cells
Answer:Please find the attachment
Explanation:
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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The Weak Ionization constant (Ka) for HCOOH is equal to:
Please help me lol
Answer:
[tex]Ka=\frac{[H^+][HCOO^-]}{[HCOOH]}[/tex]
Explanation:
Hello,
In this case, the weak ionization reaction for formic acid is:
[tex]HCOOH(aq)\rightleftharpoons H^+(aq)+HCOO^-(aq)[/tex]
In such a way, we simply recall the law of mass action in order to represent the weak ionization constant, Ka, for such process, by taking into account that the concentration of products is divided over the concentration of reactants as shown below:
[tex]Ka=\frac{[H^+][HCOO^-]}{[HCOOH]}[/tex]
Best regards.
Answer:
[tex]Ka=\frac{[CH_3COO^-][H^+]}{[CH_3COOH]}[/tex]
Explanation:
In this case we have to start with the ionization reaction of [tex]CH_3COOH[/tex], so:
[tex]CH_3COOH~<->~CH_3COO^-~+~H^+[/tex]
With this in mind we can calculate the mathematical expression of Ka (The production of hydronium ions [tex]H^+[/tex]), so:
[tex]Ka=\frac{[CH_3COO^-][H^+]}{[CH_3COOH]}[/tex]
I hope it helps!
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.
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!
