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4 years ago

The pictures to the right, show two different models

Chemistry

2 answers:

OverLord2011 [107]4 years ago

8 0

Answer:model B

Explanation:

Edge 2020

Svetllana [295]4 years ago

6 0

Answer:

The pictures to the right, show two different models of the atom. Type in the letter of your answer.

Which model best represents Dalton’s atomic theory?

Which model best represents the modifications to the theory that Thomson’s results made necessary?

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Define atomic mass unit?

sveticcg [70]

Atomic mass unit is the standard unit that is used for indicating mass on an atomic or molecular scale

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3 years ago

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How many neutrons are there in 9 molecules of P4 with mass number 31 and proton number 15?

aalyn [17]

A = mass number which is equal to the total number of protons + number of neutrons, Z= atomic number of any element which is also indicates Number of protons or number of electron in the given atom.

The formula to calculate neutron would be :

mass number - proton

31 - 15 = 16

Thus 16 neutrons are found in one atom of P

There are 4 atom in one molecule

Thus

4 atom /1 molecule * 9 molecule * 16 neutron / 1 atom

= 4*9*16= 576 neutrons

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3 years ago

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how long does it take (in minutes) for light to reach Saturn from the sun , a distance of 1.466x10^9 km

vampirchik [111]

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3 years ago

Consider the reaction of metallic copper with iron(!!) to give copper(ll) and ironin 0.77V Fe* (aq) + e-Fe (aq) Cup (aq) + 2e --

frosja888 [35]

Answer :

(a) The anode and cathode will be $E^o_{(Cu^{2+}/Cu)}$

and $E^o_{(Fe^{3+}/Fe^{2+})}$ respectively.

(b) The emf of cell potential is 1.022 V

Explanation :

(a) The standard reduction potentials for iron and copper are:

$E^o_{(Fe^{3+}/Fe^{2+})}=0.77V\\E^o_{(Cu^{2+}/Cu)}=0.34V$

In the voltaic cell, the oxidation occurs at an anode which is a negative electrode and the reduction occurs at the cathode which is a positive electrode.

From the standard reduction potentials we conclude that, the substance having highest positive $E^o$ potential will always get reduced and will undergo reduction reaction.

So, iron will undergo reduction reaction will get reduced. Copper will undergo oxidation reaction and will get oxidized.

The given cell reactions are:

Oxidation half reaction (anode): $Cu\rightarrow Cu^{2+}+2e^-$

Reduction half reaction (cathode): $Fe^{3+}+1e^-\rightarrow Fe^{2+}$

Thus, the anode and cathode will be $E^o_{(Cu^{2+}/Cu)}$

and $E^o_{(Fe^{3+}/Fe^{2+})}$ respectively.

(b) Now we have to calculate the potential of a cell.

Oxidation half reaction (anode): $Cu\rightarrow Cu^{2+}+2e^-$

Reduction half reaction (cathode): $Fe^{3+}+1e^-\rightarrow Fe^{2+}$

In order to balance that electrons, we will multiple the reduction reaction by 2, we get:

Oxidation half reaction (anode): $Cu\rightarrow Cu^{2+}+2e^-$

Reduction half reaction (cathode): $2Fe^{3+}+2e^-\rightarrow 2Fe^{2+}$

The overall cell reaction will be,

$2Fe^{3+}+Cu\rightarrow Cu^{2+}+2Fe^{2+}$

$E^o_{[Fe^{3+}/Fe^{2+}]}=2\times 0.77V=1.54V$

$E^o_{[Cu^{2+}/Cu]}=0.34V$

To calculate the $E^o_{cell}$ of the reaction, we use the equation:

$E^o_{cell}=E^o_{cathode}-E^o_{anode}$

$E^o=E^o_{[Fe^{3+}/Fe^{2+}]}-E^o_{[Cu^{2+}/Cu]}$

$E^o=1.54V-(0.34V)=1.20V$

Now we have to calculate the cell potential.

Using Nernest equation :

$E_{cell}=E^o_{cell}-\frac{0.0592}{n}\log \frac{[Fe^{2+}]^2[Cu^{2+}]}{[Fe^{3+}]^2}$

where,

n = number of electrons in oxidation-reduction reaction = 2

$E_{cell}$ = emf of the cell = ?

Now put all the given values in the above equation, we get:

$E_{cell}=1.20-\frac{0.0592}{2}\log \frac{(0.20)^2(0.25)}{(0.0001)^2}$

$E_{cell}=1.022V$

Therefore, the emf of cell potential is 1.022 V

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3 years ago

in the chemical equation HCI+CaCO3 which element cannot be apart of the products a carbon b chlorine c nitrogen d oxygen

FromTheMoon [43]

Answer:

Nitrogen

Explanation:

The element nitrogen cannot be a product in the given reaction.

The reaction is;

HCl + CaCO₃

According to the law of conservation of matter, "matter is neither created nor destroyed in the cause of a chemical reaction".

The law suggests that, in a chemical reaction, we end up with the same species we started with. Although due to rearrangement of bonds, new compounds can form;

Starting atoms

These species will also be found in the product.

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4 years ago