please help???? i dont know this

Answer:

The answer should be A

Explanation:

Answer:

Leaving a Copper penny in vinegar until it turns green

Explanation:

the others are physical changes. when copper penny is put in vinegar, a reactive oixde layer is formed which is green in colour. namely, Cu(II) acetate.

The green growing on the penny of copper and the rust forming on the nail of iron are chemical changes. Boiling away salt water, scraping iron filings from a mixture of sand with a magnet, and breaking a rock with a hammer, are physical changes.

Heat can travel from one place to another in three ways: Conduction, Convection and Radiation.

A reagent us a chemical substance applied in a chemical reaction to bring about a change in the chemical reaction process. The reagent that is appropriate to carry out the conversion is Ethanol (CH3CH2OH).

Organic Reactions are reactions taking place in organic compounds and they can take various forms such as electrophilic addition reaction or nucleophilic substitution reactions.

From the assumed diagram below, the reaction takes place in an unimolecular nucleophilic reaction SN1 mechanism in which a racemic mixture produce an organic compound and an enantiomer.

For the reaction to take place, the best organic reagent to us is known as ethanol (CH3CH2OH). This is because the organic reagent is a solvent that acts as a Nucleophile.

In the reaction, bromine (Br) is the leaving group, after it detaches from the racemic compound, it forms a carbonation in which the Ethanol CH3CH2OH attacks at the carbonation site.

Therefore, we can conclude that the Reagent necessary to carry out the conversion is Ethanol (CH3CH2OH)

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Answer:

1. Ar, Cl, Al, Mg, Na

2. O, S, Se, Te, Po

Explanation:

Just remember the trends. From left to right, atomic radius decreases because proton increases and pulls electrons closer. From top to bottom, atomic radius increases because there are more electron shells.

Answer:

Whats the question

Explanation:

Answer:

Where is the question?

Explanation:

Anyways hru all? I've been pretty good

Answer:3 9 jackalopes

Explanation: given that five rabbits are equal to eight hares and ten hares are also equal to thirteen jackalopes:

19 rabbits =31 hares by (19×8)/5 so 31hares =39 jackal by 31×13/10

Answer:

ano pong topik po yan

Answer:

im going to go with letter c

Explanation:

Answer:

Changes can occur to physical properties of a substance, but the chemical composition of the substance remains the same.

Explanation:

Physical change is a change in which there is no change in the chemical arrangement and thus there is no redistribution of atoms. No new substances are formed. There is only change in size, shape and phase etc.

[tex]H_2O(l)[/tex]→[tex]H_2O(g)[/tex]

Chemical change is a change in which there is change in the chemical arrangement and thus there is  redistribution of atoms. which leads to formation of new substances.

[tex]2Na+Cl_2[/tex]→[tex]2NaCl[/tex]

Answer:

mass of water, mw = 300g = 0.3kg

∆Tw = (80 - 20) °C

volume of air, va = 100m³

mass of air, ma = 100g = 0.1kg

∆Ta = ?

H = mc∆T

Hw = mwcw∆Tw

Hw = 0.3*4200*60

Hw = 75600J

Hw = 75.6 kJ

All the above heat energy got absorbed by air,

that is; Ha = 75600J

since it's given that the heat was absorbed by a specific amount of volume of air

then specific capacity of volume of air is

then,

ca = Ha × density

ma temp

then,

Ha = vaca∆Ta

where, ca = volumetric heat capacity of air = 0.012kJ/m³°C

75.6kJ = 100m³ × 0.012kJ/m³°C × ∆Ta

75.6 = 1.2/°C × ∆Ta

∆Ta = 63°C

63°C is the temperature change in air.

Answer:

Neptune and Saturn although Neptune isn't on there so just Saturn.

hope it'll help ya out!

Answer:

fussion

your welcome

Answer:

Plate tetonics theory is the idea that different tectonic plates, are constantly moving and changing the surface of our Earth. They can move in three ways, convergent, divergent, and transform. Seafloor Spreading is like an example of divergent movement. When the plates diverge from each other it can create various changes such as creating a new sea floor. You can use seafloor spreading as an example of the plate tetonics theory.

Explanation:

Answer:

An object's thermal energy is dependent upon its temperature and mass. The higher the temperature of a given quantity of a substance, more is its thermal energy. Similarly, for the same temperature, higher mass of a substance will contain more thermal energy

Answer:

5.62•100=562cm

5310mL/1000=5.310L

85mg/1000=0.085g

2.54L•1000=2540mL

455g/1000=0.455kg

5500mm/1000=5.500m

0.00045m•100=0.045cm

Whenever the units increase, you divide. (LLS)

Whenever the units decrease, you multiply. (SSL)

Answer:

The gain in mass by the negative electrode is the same as the loss in mass by the positive electrode. So the copper deposited on the negative electrode must be the same copper ions that are lost from the positive electrode.

Answser:

This sunflower must be a young one because a sunflower turns toward the sun when they are young. Once they mature they will prematurally stay facing east. with this knowledge we can exclude some of tghe answers and leave the correct one remaining. It is not C becasue sunflowers do not hibernate. They lay dormante in the winter waiting for their seeds to pop out during the spring. it is not D becasue Gravitropism is a form of facing towards or away from the pull of gravity. It is nopt A because it is to simalir to Hidernation. Dormancy is staying dormant during cool temputure and ect. So our answer must be B because Phototropism is the condition that a plant growes toward light. this is why bannanas are curved and why trees grow up. So your your answer is B Phototropism.

The average atomic mass of element X that has two isotopes (one of 45.0 amu mass and 45% abundance and the other of 47.0 amu mass and 55.0% abundance) is 46.1 amu (option 1).  

The average atomic mass (A) of element X can be calculated as follows:

[tex] A = m_{1}\%_{1} + m_{1}\%_{1} [/tex]    (1)

Where:

m₁: is the mass of isotope 1 = 45.0 amu

m₂: is the mass of isotope 2 = 47.0 amu

%₁: is the abundance percent of isotope 1 = 45.0 %

%₂: is the abundance percent of isotope 1 = 55.0 %

Hence, the average atomic mass is (eq 1):

[tex] A = m_{1}\%_{1} + m_{1}\%_{1} = 45.0 amu*45.0\% + 47.0 amu*55.0\% = 45.0 amu*0.45 + 47.0 amu*0.55 = 46.1 amu [/tex]  

Therefore, the average atomic mass of element X is 46.1 amu (option 1).

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I hope it helps you!

Answer:

These are the elements or compounds that enter into a chemical reaction: Reactants

These are the substance(s) formed in a chemical reaction: Products

These are the reactants in the chemical equation C6H1206 +602 --> 6CO2 + 6H20: C6H1206 and 602

These are the reactants in the chemical equation 6 CO2 + 6H2O --> C6H1206 + 6 02: 6 CO2 + 6H2O

These are the reactants in the chemical equation 2 H2 + 02 --> 2 H2O: 2H2 and O2

These are the reactants in the chemical equation 2 H2O --> 2 H2 + O2: 2H2O

Exponential growth can lead to decreasing the population size, which represents an example of a NEGATIVE feedback loop. This control mechanism (negative feedback) is common in nature.

Negative feedback is a homeostatic self-regulatory process by which the output of a given system is fed back in order to reduce its internal fluctuations.

In a negative feedback, an amplified output from the system (e.g., in this case, a sudden increased population size) leads to its self-inhibition.

This control mechanism (negative feedback loop) helps to maintain the homeostatic balance of the entire system in order to reach a set point.

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Answer:

48g of Magnesium.

Explanation:

We know that:

Mole=given mass/molar mass

Then, moles of aluminum = 54/27 = 2.

A/c to question ,

For 2 moles of magnesium it's mass is 2×24=48g.

Hence, the required mass for same number of magnesium atoms is 48g.

(Hope this helps can I pls have brainlist (crown)☺️)

Answer:

10CO²+4H²O

Explanation:

that Brainliest me pls

The layer of Earth which provide transfer from the white core to the lithosphere that fuels convection is the mantle.

A mantle can be described as a layer inside a planetary body bounded above a crust and below a core. Mantles are composed of rock or ice and are usually the largest massive layer of the planetary body.

The mantle layer of the earth is a layer of silicate rock between the crust and the outer core. The mass of the mantle of 4.01 × 10²⁴ kg which is 67% of the mass of the Earth. It's a thickness of 2,900 kilometers making up about 84% of Earth's volume.

The mantle layer is predominantly solid, but it behaves as a viscous fluid. At mid-ocean ridges, partial melting of the mantle produces oceanic crust, and at subduction zones, partial melting of the mantle produces continental crust.

The temperatures range of the mantle from 200 °C at the upper boundary with the crust to  4,000 °C  at the core-mantle boundary. The convection of the mantle is a chaotic process,  the mantle transfers heat that fuels convection.

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Answer:

This is the answer but I'm sure from all answers. I hope my answer help you.

The number of units of aluminum chloride (AlCl₃) that can be produced from 30 atoms of aluminum (Al) is 30 units

The balanced equation for the reaction is given below:

2Al + 3Cl₂ — > 2AlCl₃

From the balanced equation above,

2 atoms of Al reacted to produce 2 units of AlCl₃.

With the above information, we can determine the number of units of AlCl₃ that can be produced by the reaction of 30 atoms of Al. This can be obtained as follow:

From the balanced equation above,

2 atoms of Al reacted to produce 2 units of AlCl₃.

Therefore,

30 atoms of Al will also react to produce 30 units of AlCl₃.

Thus, 30 units of AlCl₃ were obtained from the reaction.

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Answer: B

Explanation:

Answer:

To calculate half life, divide original value by 2.

1.

FOUR HALF LIVES = divide original value by 2, 4 times.

40÷ 2 = 20

20 ÷ 2 = 10

10 ÷ 2 = 5

5 ÷ 2 = 2.5g

2. AFTER TEN DAYS (TWO HALF LIVES)

140 ÷ 2 = 70

70÷ 2 = 35g

AFTER TWENTY DAYS (FOUR HALF LIVES)

140 ÷ 2 = 70

70 ÷ 2 = 35

35 ÷ 2 = 17.5

17.5 ÷ 2 = 8.75g

Answer: B would be the correct answer

Explanation: You will need to use P1V1/T1=P2V2/T2

So

P1= 81.0kPa /101 =0.799atm

V1=0.4L

T1=25.0C +273.15K= 298.15K

P2= 101kPa /101 = 1atm

V2=0.25L

T2= ?

T2=P2V2T1/P1V1

(1.0atm)(0.25L)(298.15K)/(0.799atm)(0.4L) =233.22K-273.15=-39.92C

Answer:

Here

Explanation:

When the atom absorbs energy, it can move to a higher energy state, or excited state. Under what circumstances can an atom emit a photon? A photon is emitted when an atom moves from an excited state to its ground state or to a lower-energy excited state.