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lawyer [7]
3 years ago
5

When 4.979 grams of a hydrocarbon, CxHy, were burned in a combustion analysis apparatus, 16.20 grams of CO2 and 4.976 grams of H

2O were produced.
In a separate experiment, the molar mass of the compound was found to be 54.09 g/mol. Determine the empirical formula and the molecular formula of the hydrocarbon.
Chemistry
1 answer:
dimaraw [331]3 years ago
5 0
For Hydrocarbon combustion:

CₓHₐ + O₂ → xCO₂ + a/2 H₂O

Moles of CO₂ = 16.2 / 44 = 0.37
Moles of Carbon = 0.37
Moles of H₂O = 4.976 / 18 = 0.28
Moles of Hydrogen = 0.28 x 2 = 0.56

Molar ratio = C : H = 1 : 1.5
= 2 : 3
C₂H₃

Mass of empirical unit = 12 x 2 + 1 x 3
= 27
Mr = 54.09
Number of empirical units repeated: 54.09 / 27
= 2

Molecular formula = C₄H₆
You might be interested in
Potassium nitrate has a lattice energy of -163.8 kcal/mol and a heat of hydration of -155.5 kcal/mol.
Brut [27]

Answer:

<em>293.99 g </em>

OR

<em>0.293 Kg</em>

Explanation:

Given data:

Lattice energy of Potassium nitrate (KNO3) = -163.8 kcal/mol

Heat of hydration of KNO3 = -155.5 kcal/mol

Heat to absorb by KNO3 = 101kJ

To find:

Mass of KNO3 to dissolve in water = ?

Solution:

Heat of solution = Hydration energy - Lattice energy

                           = -155.5 -(-163.8)

                           = 8.3 kcal/mol

We already know,

1 kcal/mol = 4.184 kJ/mole

Therefore,

= 4.184 kJ/mol x 8.3 kcal/mol

= 34.73 kJ/mol

Now, 34.73 kJ of heat is absorbed when 1 mole of KNO3 is dissolved in water.

For 101 kJ of heat would be

= 101/34.73

= 2.908 moles of KNO3

Molar mass of KNO3 = 101.1 g/mole

Mass of KNO3 = Molar mass x moles

                         = 101.1 g/mole  x  2.908

                         = 293.99 g

                         = 0.293 kg

<em><u>293.99 g potassium nitrate has to dissolve in water to absorb 101 kJ of heat. </u></em>     

4 0
4 years ago
How many dimes could you trade for 360 pesos? $1 = 1500 pesos.
sveta [45]

Answer:

The correct option is (d).

Explanation:

It is given that,

1$ = 1500 pesos

We need to convert 360 pesos into dimes

We can convert 360 pesos to dollars as follows:

360\ \text{pesos}=\$\dfrac{1}{1500}\times 360\\\\=$0.24

360 pesos is equal to $0.24

Also, 1 dollar = 10 dimes

We can covert 0.24 dollar to dimes as follows :

0.24 dollar = 10 × 0.24 dimes

0.24 dollar = 2.4 dimes

or

360 pesos = 2.4 dimes

7 0
3 years ago
Will mark brainliest
OverLord2011 [107]

Answer:

4. Principal and Azimuthal (subsidiary) quantum number

5.Principal, Azimuthal (subsidiary), and magnetic quantum number

6. 10 electrons

7. 32 electrons

8. 36 electrons

Explanation:

4. Principal and Azimuthal (subsidiary) quantum number because in 4d, 4 represent principal quantum number and d- represents azimuthal quantum number (having l- value as 3)

5.Principal, Azimuthal (subsidiary), and magnetic quantum number are the first three because 2 stands for principal, s-for azimuthal (l=0) and magnetic quantum number for s- orbital= 0

6. 10 electrons, because for sublevel with l= 3, is a d-sub-level, and d- can take 10-electrons

7. 32 electrons, using the relationship 2×n^2 for the maximum number of electrons in a shell,

,n= 4 , hence 2×4^2= 32

8. 36 electrons, because n=4 and n= 3 can have the maximum configuration of [Ar]4s^2 3d^10 4p^6

This will sum up to 36- electrons, since Argon has 18 -electrons.

18+2+10+6=36 electrons

8 0
3 years ago
If you have 100 ml of a 0.10 m tris buffer (pka 8.3) at ph 8.3 and you add 3.0 ml of 1.0 m hcl, what will be the new ph?
sukhopar [10]

The new pH is 7.69.

According to Hendersen Hasselbach equation;

The Henderson Hasselbalch equation is an approximate equation that shows the relationship between the pH or pOH of a solution and the pKa or pKb and the ratio of the concentrations of the dissociated chemical species. To calculate the pH of the buffer solution made by mixing salt and weak acid/base. It is used to calculate the pKa value. Prepare buffer solution of needed pH.

                       pH = pKa + log10 ([A–]/[HA])

Here, 100 mL  of  0.10 m TRIS buffer pH 8.3

                 pka = 8.3

         0.005 mol of TRIS.

∴  8.3 = 8.3 + log \frac{[0.005]}{[0.005]}

<em>    </em>inverse log 0 = \frac{[B]}{[A]}

   \frac{[B]}{[A]} = 1

Given; 3.0 ml of 1.0 m hcl.

           pka = 8.3

           0.003 mol of HCL.

pH = 8.3 + log \frac{[0.005-0.003]}{[0.005+0.003]}\\pH = 8.3 + log \frac{[0.002]}{[0.008]}\\\\pH = 8.3 + log {0.25}\\\\pH = 8.3 + (-0.62)\\pH = 7.69

Therefore, the new pH is 7.69.

Learn more about pH here:

brainly.com/question/24595796

#SPJ1

 

8 0
2 years ago
The isotope of carbon used in archaeological dating is 14^6C . How many protons, neutrons, and electrons does an atom of 14^6C h
vampirchik [111]

Answer:

6

8

6

Explanation:

 Isotope given:

                       ¹⁴₆C

In specie written as this;  

   Superscript  = Mass number

   Subscript  = Atomic number

To find the protons, it is the same as the atomic number;

                Protons  = Atomic number  = 6

Neutrons have no charges;

 Neutrons  = Mass number - Atomic number  =

  Neutrons  = 14 - 6  = 8

The number of electrons is the same as the atomic number = 6

8 0
3 years ago
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