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Nezavi [6.7K]
3 years ago
14

How can you tell if a substance is a mixture or a compound

Chemistry
1 answer:
s344n2d4d5 [400]3 years ago
3 0

Answer:

If a substance can be separated into its elements, it is a compound. If not it is a mixture.

You might be interested in
Write the electronic configuration of Cr^2+ (z=24) and predict the number of electrons having n+1 value equal to 3
leonid [27]

Answer:

(a) Cr²⁺: 1s² 2s²2p⁶ 3s²3p⁶ 3d⁴; (b) eight  

Explanation:

(a) Electron configuration of Cr

(i). Locate chromium in the Periodic Table.

It's Element 24, so  in Period 4, Group 3.

(ii). Write its electron configuration

Remember that Cr is one of those exceptions to the Aufbau principle.

Instead of the predicted electron configuration of [Ar] 4s²3d⁴, we get the configuration [Ar] 4s3d⁵.

The reason is that this this configuration minimizes electron repulsion.

(b) Write the electron configuration for Cr²⁺.

Now, we must remove two electrons from a chromium atom.

The electron in the 4s orbital is removed first, because this orbital is further from the nucleus, making electrons easier to remove.

So, we remove the 4s electron, and  then a 3d electron.

The electron configuration of Cr²⁺ is

[Ar]3d⁴ or 1s² 2s²2p⁶ 3s²3p⁶ 3d⁴

(c). Electrons with n + l = 3

The orbitals with n + l = 3 are those covered by the third arrow down in the order of orbital energies:

2p (n = 2, l = 1) and 3s (n = 3, l = 0)

The 2p orbitals can hold six electrons, and the 3s orbital can hold two.

Both subshells are filled in a Cr²⁺ ion, so there are eight electrons

with n+ l = 3.

3 0
3 years ago
I don’t understand how to find these please help
ddd [48]

Answer:

8 shared electrons

Explanation:

When you are looking for the number of shared electrons via the equation:

S = N-A

Where:

S = means the shared electrons

N = Needed electrons

A = available electrons

"Needed electrons" means how many electrons does it need to have a noble gas configuration, in this case, to complete the octet rule.

"Available electrons" means how many valence electrons is actually available considering the compound or the elements involved in the compound.

To get the needed electrons, treat the elements involved separately.  We have a silicon (Si) atom and 4 chlorine (chlorine) atoms in this compound. Let's list it down first:

              Number of atoms

Si                      1

Cl                     4

Next step is to determine how many electrons should it have in its outer shell to achieve the octet rule. Both of them in this case would be 8. Multiply that by the number of atoms and add up the needed electrons to determine how many you will need for this particular compound.

        <u>      Number of atoms             Electrons to achieve Octet       Needed</u>

Si                      1                      x                         8                           =       8

Cl                     4                      x                         8                           = <u>     32</u>

                                                                     TOTAL:                              40

This is now our N. N = 40 electrons

Next step is to determine how many we actually have. Your clue in determining how many valence electrons the atom has is the group. Silicon is in Group 4A, this means it has 4 valence electrons. Chlorine is in Group7A, so ths means it has 7 valence electrons.

So first we write the number of atoms again, then in the next column, you write down the actual number of valence electrons and multiply them. Sum it up to see how many electrons available  in this particular compound.

        <u>      Number of atoms             Valence electrons                 Available</u>

Si                      1                      x                         4                           =      4

Cl                     4                      x                         7                          = <u>     28</u>

                                                                     TOTAL:                              32

This is now our A. A = 32 electrons

Now we apply this:

S = N - A

N = 40 electrons

A =  32 electrons

S = 40 - 32 = 8

Number of shared electrons is 8

5 0
3 years ago
A book is sitting on a desk. The area of contact between the book and the desk is 0.06 m2 of the body's weight is 30 N what is t
tekilochka [14]

Answer:

500N/m²

Explanation:

The Pressure can be calculated using the formula:

P = F/A

Where;

F = force (N)

A = Area (m²)

Based on the information provided in the question, F = 30N, A = 0.06m²

P = F/A

P = 30/0.06

P = 500N/m²

7 0
3 years ago
6. Cuando se oxidan en el aire 12,120 g de vapor de Zinc se obtienen 15,084 g del óxido. ¿Cuál es la fórmula empírica del óxido?
Eddi Din [679]

Answer:

 12120 g  +    O2        =    15084 g

m Zn = 12.120 Kg

m óxido = 15.084 Kg

1. calcular la masa de cinc en gramos

g = 12,120 Kg x 1000 = 12120 g de cinc

g = 15.084 Kg x 100 = 15084 g de oxígeno

2.  calcular gramos de Oxigeno

g O = 15084 g - 12120 g = 2964 g O2

3. calcular % de Zn y O

%m/m ( m soluto / m solc.) x 100

%m/m (Zn) =  ( 1210 g / 15084 g ) x 100

% m/m (Zn) = 80.35 % = 80.35 g

%m/m (O) =  ( 2964 g / 15084 g ) x 100

% m/m (Zn) = 19.65 %  = 19.65 g

4. Calcular moles de cada elemento

Zn: 80.35 g / 65.38 g/mol = 1.228 mol

O: 19.65 g / 16 g/mol = 1.228 mol

5. dividir entre el menor de los elementos

Zn: 1.228 mol / 1.228 mol = 1

O: 1.228 mol / 1.228 mol = 1

6. Fórmula empírica: ZnO

3 0
3 years ago
Which of the following is an anion?<br> A. O^2- <br> C. Al^3+ <br> D. H
kifflom [539]
The correct answer is A. O^2-
6 0
3 years ago
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