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bulgar [2K]
3 years ago
5

A 0.1510 gram sample of a hydrocarbon produces 0.5008 gram CO2 and 0.1282 gram H2O in combustion analysis. Its

Chemistry
1 answer:
Over [174]3 years ago
4 0
In a combustion of a hydrocarbon compound, 2 reactions are happening per element:

C + O₂ → CO₂
2 H + 1/2 O₂ → H₂O

Thus, we can determine the amount of C and H from the masses of CO₂ and H₂O produced, respectively.

1.) Compute for the amount of C in the compound. The data you need to know are the following:
Molar mass of C = 12 g/mol
Molar mass of CO₂ = 44 g/mol
Solution:
0.5008 g CO₂*(1 mol CO₂/ 44 g)*(1 mol C/1 mol CO₂) = 0.01138 mol C
0.01138 mol C*(12 g/mol) = 0.13658 g C

Compute for the amount of H in the compound. The data you need to know are the following:
Molar mass of H = 1 g/mol
Molar mass of H₂O = 18 g/mol
Solution:
0.1282 g H₂O*(1 mol H₂O/ 18 g)*(2 mol H/1 mol H₂O) = 0.014244 mol H
0.014244 mol H*(1 g/mol) = 0.014244 g H

The percent composition of pure hydrocarbon would be:
Percent composition = (Mass of C + Mass of H)/(Mass of sample) * 100
Percent composition = (0.13658 g + 0.014244 g)/(<span>0.1510 g) * 100
</span>Percent composition = 99.88%

2. The empirical formula is determined by finding the ratio of the elements. From #1, the amounts of moles is:

Amount of C = 0.01138 mol
Amount of H = 0.014244 mol

Divide the least number between the two to each of their individual amounts:
C = 0.01138/0.01138 = 1
H = 0.014244/0.01138 = 1.25

The ratio should be a whole number. So, you multiple 4 to each of the ratios:
C = 1*4 = 4
H = 1.25*4 = 5

Thus, the empirical formula of the hydrocarbon is C₄H₅.

3. The molar mass of the empirical formula is

Molar mass = 4(12 g/mol) + 5(1 g/mol) = 53 g/mol
Divide this from the given molecular weight of 106 g/mol
106 g/mol / 53 g/mol = 2
Thus, you need to multiply 2 to the subscripts of the empirical formula.

Molecular Formula = C₈H₁₀

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The sum of gravitational potential energy and kinetic
Firlakuza [10]

Answer:

Explanation:

Mechanical energy = Gravitational potential energy + kinetic energy

Time            Gravitational potential energy        kinetic energy         Total ME

0                                    4                                                0                        4

2                                     2                                               2                        4

4                                     0                                               4                        4

6                                     2                                               2                        4

8                                     4                                               0                        4

and so on  .....

We see that total mechanical energy is always 4 which is constant .

So gravitational and kinetic energy changes cyclically but total mechanical energy is constant .

         

7 0
3 years ago
H2(g) + Br2(l) ⇄ 2HBr(g) Kc = 4.8 × 108
elena-14-01-66 [18.8K]

Answer:

  • 1.5 × 10⁻⁹M

Explanation:

<u>1. Equilibrium equation</u>

  • H₂(g) + Br₂(l) ⇄ 2HBr(g)

<u>2. Equilibrium constant</u>

The liquid substances do not appear in the expression of the equilibrium constant.

    k_c=\dfrac{[HBr(g)]^2}{[H_2]}=4.8\times 10^8M

<u>3. ICE table.</u>

Write the initial, change, equilibrium table:

Molar concentrations:

         H₂(g) + Br₂(l) ⇄ 2HBr(g)

I          0.400                   0

C           - x                      +2x

E         0.400 - x              2x

<u>4. Substitute into the expression of the equilibrium constant</u>

     4.8\times 10^8=\dfrac{(2x)^2}{0.400-x}

<u>5. Solve the quadratic equation</u>

  • 192,000,000 - 480,000,000x = 4x²
  • x² + 120,000,000x - 48,000,000 = 0

Use the quadratic formula:

       

x=\dfrac{-120,000,00\pm\sqrt{(120,000,000)^2-4(1)(-48,000,000}}{2(1)}

The only valid solution is x = 0.39999999851M

Thus, the final concentration of H₂(g) is 0.400 - 0.39999999851 ≈ 0.00000000149 ≈ 1.5 × 10⁻⁹M

8 0
3 years ago
what volume will it occupied 40 degrees celsius a gas sample was collected when a temperature is 27 degrees celsius and the volu
love history [14]
  • T_1=27°C
  • T_2=40°C
  • V_1=1L
  • V_2=?

Using Charles law

\boxed{\sf \dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}}

\\ \sf\longmapsto V_1T_2=V_2T_1

\\ \sf\longmapsto 1(40)=27V_2

\\ \sf\longmapsto V_2=\dfrac{40}{27}

\\ \sf\longmapsto V_2=1.48\ell

7 0
2 years ago
How does reactants in photosynthesis combine to make atoms molecules
balu736 [363]

Answer:

hope this helps

Explanation:

Photosynthesis

Photosynthesis

Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's metabolic activities. This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water – hence the name photosynthesis, from the Greek phos, "light", and sunthesis "putting together". In most cases, oxygen is also released as a waste product. Most plants, algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies most of the energy necessary for life on Earth.

7 0
2 years ago
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erma4kov [3.2K]

Answer:

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Explanation:

Formula of the given compound are -

1 - Potassium Hydroxide - KOH

2 - Calcium Nitrate - Ca(NO_3)_2

The requirements for a correctly written chemical equation are -

  • Identifying reactants and products
  • Formula of reactants and products
  • Valency of elements

Example of word equation, formula equation, and chemical equation is as follows -

Aluminium + iron9(III)oxide ⇒ aluminium oxide + iron (word equation)

Al_(_s_)  + Fe_2O_3_(_s_)    ⇒   Al_2O_3_(_s_)  + Fe_(s) (formula equation)              

2Al_(_s_) + Fe_2O_3_(_s_)    ⇒   Al_2O_3_(_s_)   + 2Fe_(_s_) (chemical equation)

8 0
3 years ago
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