what is the Democratus​

Answer:

2.34

Explanation:

Answer:

Heat absorbed = mS△T

51 = ( 8.2/1000)Kg ×S (11.5)

51×1000= 8.2 (11.5)S

S = 51000/94.3

S = 540.8 J/kg K

Answer:

48 newtons

Explanation:

f=m*a

Explanation:

At sea level, the atmospheric pressure would be a little over 100 kPa (one atmosphere or 760 mm Hg). If we climb to the top of Mount Everest (the highest mountain in the world at 29,029 feet or 8848 meters), the atmospheric pressure will drop to slightly over 30 kPa (about 0.30 atmospheres or 228 mm Hg).

Hope it is helpful for you

So, what's shown here is the ion product of pure water: that is, the product of the concentrations of hydronium and hydroxide ions in pure water at 25 °C. By this relation, if you know the [H₃O⁺], you can calculate the [OH⁻], and vice-versa.

Since [H₃O⁺] × [OH⁻] = 1.0 × 10⁻¹⁴, [OH⁻] = (1.0 × 10⁻¹⁴)/[H₃O⁺].

Substituting the given [H₃O⁺] as 1.25 × 10⁻² M:

[OH⁻] = (1.0 × 10⁻¹⁴)/(1.25 × 10⁻² M) = 8.0 × 10⁻¹³ M.

Answer:

252 Joules

Explanation:

I thin k this is right, im so sorry if not!! :)

Answer:

oceans

Explanation:

Answer:

D. Ocean

Explanation:

oceans are the majority water on earth's surface located. They hold 97% of earths water.

Answer:

C

Explanation:

Check it. So u can know it

Answer:

i cant see the whats in the picture

Answer:

The temperature increases in 40.9K

Explanation:

Based on the reaction, 4 moles of aniline in combustion releasing 12800kJ to the surroundings, in this case, to the calorimeter.

To solve this question we must find the heat that releases the sample of aniline finding the moles in the sample.

With the heat released we can find the increase in Kelvin due the combustion as follows:

Moles aniline:

11.9g * (1mol / 93g) = 0.128 moles aniline

Heat released:

0.128 moles Aniline * (12800kJ / 4 moles Aniline) = 409kJ are released

Increasing in temperature:

For each 10.0kJ, the calorimeter increases its temperature in 1K. For 409kJ:

409kJ * (1K / 10.0kJ) =

Answer:

Most common oxidation states: +2, +3

M.P. 1535º

B.P. 2750º

Density 7.87 g/cm3

Characteristics: Iron is a gray, moderately active metal.

Characteristic reactions of Fe²⁺ and Fe³⁺

The [Fe(H2O)6]3+ ion is colorless (or pale pink), but many solutions containing this ion are yellow or amber-colored because of hydrolysis. Iron in both oxidation states forms many complex ions.

Aqueous Ammonia

Aqueous ammonia reacts with Fe(II) ions to produce white gelatinous Fe(OH)2, which oxidizes to form red-brown Fe(OH)3:

Fe2+(aq)+2NH3(aq)+3H2O(l)↽−−⇀Fe(OH)2(s)+2NH+4(aq)(1)

Fe3appt.gif

Aqueous ammonia reacts with Fe(III) ions to produce red-brown Fe(OH)3:

Fe3+(aq)+3NH3(aq)+3H2O(l)↽−−⇀Fe(OH)3(s)+3NH+4(aq)(2)

Fe3bppt.gif

Both precipitates are insoluble in excess aqueous ammonia. Iron(II) hydroxide quickly oxidizes to Fe(OH)3 in the presence of air or other oxidizing agents.

Sodium Hydroxide

Sodium hydroxide also produces Fe(OH)2 and Fe(OH)3 from the corresponding oxidation states of iron in aqueous solution.

Fe2+(aq)+2OH−(aq)↽−−⇀Fe(OH)2(s)(3)

Fe4appt.gif

Fe3+(aq)+3OH−(aq)↽−−⇀Fe(OH)3(s)(4)

Fe4bppt.gif

Neither hydroxide precipitate dissolves in excess sodium hydroxide.

Potassium Ferrocyanide

Potassium ferrocyanide will react with Fe3+ solution to produce a dark blue precipitate called Prussian blue:

K+(aq)+Fe3+(aq)+[Fe(CN)6]4−(aq)↽−−⇀KFe[Fe(CN)6](s)(5)

Fe5a1ppt.gif

With Fe2+ solution, a white precipitate will be formed that will be converted to blue due to the oxidation by oxygen in air:

2Fe2+(aq)+[Fe(CN)6]4−(aq)↽−−⇀Fe2[Fe(CN)6](s)(6)

Fe5a2ppt.gif

Many metal ions form ferrocyanide precipitates, so potassium ferrocyanide is not a good reagent for separating metal ions. It is used more commonly as a confirmatory test.

Potassium Ferricyanide

Potassium ferricyanide will give a brown coloration but no precipitate with Fe3+. With Fe2+, a dark blue precipitate is formed. Although this precipitate is known as Turnbull's blue, it is identical with Prussian blue (from Equation 5).

K+(aq)+Fe+2(aq)+[Fe(CN)6]3−(aq)↽−−⇀KFe[Fe(CN)6](s)(7)

Fe5b.gif

Potassium Thiocyanate

KSCN will give a deep red coloration to solutions containing Fe3+:

Fe+3(aq)+NCS−(aq)↽−−⇀[FeNCS]+2(aq)(8)

Fe5cppt.gif

No Reaction

Cl−, SO2−4

Answer:

4.) 9, 1, and 4    5.) 4, 1, and 4

Explanation:

I am not quite sure about this because I cannot remember if the coefficient (the number before the elements) is applied to every element in the compound. If it is then your number of atoms are as follows: CORRECTION: you do not have to apply the coefficient to every element only the one that is after it. So when you back and fix the error your number of atoms will be as follows:

number 4

H: 9

P: 1

O: 4

number 5:

H: 4

S: 1

O: 4

you can calculate the number of atoms present in this compound by multiplying the coefficient and the subscripts of each atom.

hope this helped you :)

Answer:

The color black absorbs most colors, while white reflects most colors.

Answer:

thank u

Explanation:

3. Convection Current

But just a tip Next time try to emphasize the question a little more ! Hope this helps :)

Explanation:

use the conversation in the image

Answer:

There are 1.8021⋅1024 molecules of CH4 in 48 grams of CH4 .

Explanation:

hope it helps you

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I'm willing to help

Answer:

The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from

n

i

=

2

to

n

f

=

6

.

A good starting point here will be to calculate the energy of the photon emitted when the electron falls from

n

i

=

6

to

n

f

=

2

by using the Rydberg equation.

1

λ

=

R

⋅

(

1

n

2

f

−

1

n

2

i

)

Here

λ

si the wavelength of the emittted photon

R

is the Rydberg constant, equal to

1.097

⋅

10

7

m

−

1

Plug in your values to find

1

λ

=

1.097

⋅

10

7

.

m

−

1

⋅

(

1

2

2

−

1

6

2

)

1

λ

=

2.4378

⋅

10

6

.

m

−

1

This means that you have

λ

=

4.10

⋅

10

−

7

.

m

So, you know that when an electron falls from

n

i

=

6

to

n

f

=

2

, a photon of wavelength

410 nm

is emitted. This implies that in order for the electron to jump from

n

i

=

2

to

n

f

=

6

, it must absorb a photon of the same wavelength.

Answer and Explanation:

The empty spaces should be completed step-by-step as follows:

First line:

Element symbol: La (it is the corresponding element for the atomic number 57)

Mass number = Atomic number + Neutrons = 57 + 82 = 139

Nuclear symbol: ¹³⁹₅₇ La because the atomic number is 57 and mass number is 139.

Protons: 57 (is equal to the atomic number for a neutral atom)

Electrons in neutral atom = Atomic number = 57

Second line:

Element symbol: La (it is the corresponding element for the atomic number 57 and mass number 138)

Atomic number: 57 (from the Periodic Table, for La)

Mass number = 138 (from the nuclear symbol)

Protons: 57 (is equal to the atomic number for a neutral atom)

Neutrons = Mass number - Atomic number = 138 - 57 = 81

Electrons in neutral atom = Atomic number = 57

Third line:

Atomic number: 26 (from the Periodic Table, for the element Fe)

Protons: 26 (is equal to the atomic number for a neutral atom)

Neutrons = Mass number - Atomic number = 59 - 26 = 33

Nuclear symbol: ⁵⁹₂₆ Fe because the atomic number is 26 and mass number is 26.

Answer:

I'm pretty sure its D

Explanation:

It says the best that explains. D states that when it has less energy that it the molecules will collide. And they would to make a liquid. So thats why its D.

Answer:

0.0039 mol/L

The molar solubility is 0.0039 mol/L, thus the common ion effect has reduced the solubility from 0.016 mol/L for Ag2SO4 in pure water to 0.0039 mol/L in the Na2SO4 solution.

Explanation:

Answer:

Explanation:

5.6

According to the stoichiometry of the given chemical equation, 11.2 grams  of nitrogen is required to react with 16 grams of oxygen.

Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.

A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .

The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.

Learn more about chemical equation,here:

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Answer:

179g

Explanation:

Molar ratio for Copper : Lithium is

1:2

If there are 89.5g of copper

Grams for Lithium= 89.5 × 2 = 179g of Lithium

The amount of lithium are formed from the reaction if you begin with 89.5 grams of copper is 19.6 grams.

Mass can be converted into moles by using the below equation as:

n = W/M, where

W = given mass

M = molar mass

Moles of 89.5g of copper = 89.5g / 63.5g/mol = 1.4 mol

Given chemical reaction is:

Cu + Li₂S → 2Li + CuS

From the stoichiometry of the reaction, it is clear that

1.4 mole of Cu = produces 1.4 mole of CuS

1.4 mole of CuS = produced by 1.4 mole of Li₂S

1.4 mole of Li₂S = produces 2×1.4=2.8 moles of Li

Mass of 2.8 moles of Li = (2.8mol)(7g/mol) = 19.6g

Hence resultant mass of lithium is 19.6g.

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Answer:

A pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.

Explanation:

In a voltaic cell, oxidation occurs at the anode and reduction occurs at the cathode.

Hence, there is a build up of positive ions at the anode and a build up of negative ions at the cathode. This tends to disrupt the electrical neutrality of the half cells.

Hence, there is a need for negative ions in the salt bridge to flow towards the anode and positive ions in the salt bridge to flow towards the cathode in order to maintain the electrical neutrality of the cells.

Hence, a salt bridge provides a pathway by which counterions can flow between the half-cells without the solutions in the half-cell totally mixing.

The reactions are a bit poorly written. While it's true that aqueous H₂CO₃ is produced in this neutralization reaction, the H₂CO₃ rapidly decomposes to yield CO₂(g) and H₂O(l). Writing the product as H₂CO₃(aq) in the net ionic equation is unnecessarily confusing since it portrays the substance as nonionizing yet water-soluble.

In any case, the Na⁺ and the Cl⁻ are the spectator ions here.  

Answer:

I don’t mnow

Explanation: