What were the first 5 planets that were observed? Why were those the only ones? Help pls!

Answer:

Test answers

1. Water carving out a limestone cave

2. Oxidation

3. Acid rain

(Got 100%)

Explanation:

The primary agents of chemical weathering are water, oxygen and acids. So acid rain is an agent of chemical weathering. Option C is correct.

Water, and many chemical compounds found in water, is the main agent of chemical weathering.  One of the most abundant rock-forming minerals, chemically reacts with water and water-soluble compounds to form clay.

Water contains many weak acids such as carbonic acid. The primary agents of chemical weathering are water, oxygen and acids.

These react with surface rocks to form new minerals that are stable in, or in equilibrium with, the physical and chemical conditions present at the earth's surface.

Hence, option C is correct.

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Answer:

Hence, the wavelength of the photon associated is 1282 nm.

Explanation:

Answer:

V1/n1 = V2 /n2

0.236/0.306 = V2/ 4.40

V2 = 3.39 L

Answer:

some example includes:

gold, copper, oxygen, chlorine, diamond

Explanation:

The mass of PbI2 produced from a trace amount of 630mL of 0.268M KI solution is 39.2 g.

The equation of the reaction is; 2KI(aq)+Pb(NO3)2(aq) → PbI2(s) + 2KNO3(aq)​

From the question, number of moles of KI = 630/1000 L × 0.268M = 0.169 moles

Now;

2 moles of KI is required to precipitate 1 mole of PbI2

0.169 moles of KI is required to precipitate 0.169 moles × 1 mole/2 moles

= 0.085 moles

Mass of PbI2 = Number of moles of PbI2 × Molar mass

Mass of PbI2 = 0.085 moles × 461.01 g/mol

Mass of PbI2 = 39.2 g

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Answer:

Atomic number: 26

Atomic mass: 56

Net charge: +3

Explanation:

This problem is providing the ionic radius of an anion, A²⁻ as 0.290 nm and asks for that of the cation A²⁺ in comparison to the former.

Firstly, we need to recall the concept of ionic radius, as the distance between the nucleus and the outermost electron shell of an ion. In such a way, we can have two scenarios:

1. Anions result from the gain of electrons exhibited by a nonmetal, which means they turn out bigger than the neutral atom.

2. Cations result from the loss of electrons exhibited by a metal, which means they turn out smaller than the neutral atom.

With the aforementioned, we infer that the cation A²⁺, will me smaller than the anion A²⁻, which means it will have an ionic radius smaller than 0.290 nm.

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Answer:  E

1

−

E

4

=

Δ

E

=

−

2.18

×

10

−

18

J

(

1

n

2

f

−

1

n

2

i

)

=

−

2.18

×

10

−

18

J

(

1

1

2

−

1

4

2

)

=

−

2.18

×

10

−

18

J

(

15

16

)

=

−

2.04

×

10

−

18

J

After you obtain the energy, then you can realize that that energy has to correspond exactly to the energy of the photon that came in:

|

Δ

E

|

=

E

photon

=

h

ν

=

h

c

λ

where  

h

is Planck's constant,  

c

is the speed of light, and  

λ

is the wavelength of the incoming photon. Thus, the wavelength is:

⇒

λ

=

h

c

E

photon

=

(

6.626

×

10

−

34

J

⋅

s

)

(

2.998

×

10

8

m/s

)

2.04

×

10

−

18

J

=

9.720

×

10

−

8

m

=

97.20 nm

Explanation:

Heat required is mcΔT=100×0.39×50=1950 J

Solve any question of Thermodynamics with:-

The specific heat of the substance that requires 270 J of energy to raise the temperature is 2.57 J/g⁰C.

The specific heat capacity of the substance is calculated as follows;

Q = mcΔФ

where;

c = Q/mΔФ

c = (270) / (4.2 x 25)

c = 2.57 J/g⁰C

Thus, the specific heat of the substance that requires 270 J of energy to raise the temperature is 2.57 J/g⁰C.

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Answer:

0.0866 M

Explanation:

answer key

The molarity of the NaOH solution has been 0.0865 M.

The neutralization reaction of the Phosphoric acid and NaOH results in the formation of sodium phosphate and water.

The balanced chemical equation can be given as;

[tex]\rm H_3PO_4\;+\;3\;NaOH\;\rightarrow\;Na_3PO_4\;+\;3\;H_2O[/tex]

Thus for the neutralization of 1 mole of Phosphoric acid, 3 moles of NaOH has been used.

The moles of phosphoric acid in 0.100 grams sample:

Moles = [tex]\rm \dfrac{weight}{molecular\;weight}[/tex]

Moles of phosphoric acid = [tex]\rm \dfrac{0.100}{99}[/tex]

Moles of phosphoric acid = 0.001 mol

For the neutralization of 0.001 moles of NaOH:

1-mole Phosphoric acid = 3 moles NaOH

0.001-mole Phosphoric acid =0.003 moles of NaOH.

The molarity of the NaOH solution:

Molarity = [tex]\rm \dfrac{moles}{Volume\;(L)}[/tex]

Molarity of NaOH = [tex]\rm \dfrac{0.003}{0.035}[/tex]

Molarity of NaOH = 0.0865 M

The molarity of the NaOH solution has been 0.0865 M.

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Answer:

36 eggs

Explanation:

12 eggs in each carton

12 + 12 + 12 = 36 eggs

or 3 * 12 = 36 eggs

Hope this helps, have a nice day/night! :D

Answer:

It is classified as a metal and is expected to be solid at room temperature.

Explanation:

not sure but i guess it is that

Answer:

its that DDDDDD

Explanation:

i know this because its that DDDDDDDD

Answer:

Birds can sit on power lines and not get electric shocks because the electricity is always looking for a way to get to the ground. The birds are not touching the ground or anything in contact with the ground, so the electricity will stay in the power line.

Pls mark as brainliest answer if it helps you

Answer:

C

Explanation:

No reaction because not enough moles of silver are present for the reaction to occur.

Ans

This is called oxidation

Explanation:

the oxidation number of a metal ion is more than the oxidation number of metal atom

Answer:

May I assume "ethanol acid is just ethanol (it has one slightly acidic H atom).  If so, the molar mass is 46.02 g/mole.

Explanation:

We have 30 cm^3 [30 ml] of 1.0 M (1 mole/liter)  [1 dm³ = 1 liter].

That is 1 mole/liter.  30 ml would contain (0.030 liter)*(1 mole/1 liter) = 0.03 moles.

Considering the ideal gas law, a sample weighing 9.49 g occupies 68.67 L at 353 K and 2.00 atm.

Ideal gases are a simplification of real gases that is done to study them more easily. It is considered to be formed by point particles, do not interact with each other and move randomly. It is also considered that the molecules of an ideal gas, in themselves, do not occupy any volume.

An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:

P× V = n× R× T

In this case, you know:

Replacing:

2 atm× V = 4.745 moles× 0.082[tex]\frac{atmL}{molK}[/tex]× 353 K

Solving:

V = (4.745 moles× 0.082[tex]\frac{atmL}{molK}[/tex]× 353 K)÷ 2 atm

V= 68.67 L

Finally, a sample weighing 9.49 g occupies 68.67 L at 353 K and 2.00 atm.

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Answer:

verical rays

Explanation:

The rays result in shorter days are the vertical rays.

Vertical rays are another name for direct rays. Rays that are straight overhead are referred to as vertical. Because the Earth is spherical, not all the Sun's rays hit it directly or vertically.

Vertical rays lose less heat because they cover a shorter distance. Slanted rays cover more ground and dissipate more heat. Sun's vertical rays fall between the Tropics of Cancer and Capricorn, along its migratory belt.

The length of a day is determined by the Earth's rotation around its axis, which has been accelerating during the past several decades. Our days have been becoming shorter due to this tendency.

Thus, vertical rays are responsible for shorter days.

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Answer:

hiroghlipical

Explanation:

new word i just made

Answer:

that is impossible. the atomic number can only go up each group

The heat of vaporization of aluminium at 25 °C is 315.8 kilojoules per mole.

The sublimation is the phase change of a substance from solid to gas, the fusion is the phase change of a substance from solid to liquid and the vaporization is the phase change of a substance from liquid to gas. The heat of vaporization is the difference between the heat of sublimation and the heat of fusion, that is to say:

[tex]h_{v} = 326.4\,\frac{kJ}{mol}-10.6\,\frac{kJ}{mol}[/tex]

[tex]h_{v} = 315.8\,\frac{kJ}{mol}[/tex]

The heat of vaporization of aluminium at 25 °C is 315.8 kilojoules per mole.

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Answer:

Must be stable and relatively insoluble in boiling water.

Explanation:

it must be stable and relatively insoluble in boiling water and a must-have vapor pressure in boiling water that is of the order atmosphere at or more compound satisfy these conditions that will generally not separate from each other but we'll be separated from everything else.

Answer:

5.23 moles

Explanation:

How many moles of iron are present in 3.15 × 10^24 atoms of iron?

1 mole has 6.02 X 10^23 particles

so

3.15X10^ 24 atoms =( 3.15 X 10^24)/(6.02 X 10^23) =(3.15/6.02 )X 10 =

5.23 moles