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notsponge [240]
3 years ago
10

2C2H2 + 5 O2 → 4CO2 + 2H2O

Chemistry
1 answer:
shtirl [24]3 years ago
6 0

Answer:

  • Option c. ΔH reaction = - 2,512.4 kJ

Explanation:

<u>1) Data:</u>

a) ΔHf C₂H₂ = 227.4 kJ

b) ΔHf CO₂ = -393.5 kJ

c) ΔHf H₂O = -241.8 kJ

<u>2) Chemical equation:</u>

  • 2C₂H₂ + 5 O2 → 4CO₂ + 2H₂O    [see the note below about the phases]

<u>3) Necessary assumptions:</u>

  • The phases of the reactants and products in the given reaction are the same at which the standard enthalpies of formation are given.

  • The reactant O₂ is at its fundamental state (gas) which implies that the correspondant standard enthaly of formation is zero.

  • The units of the given standard enthalpies are the same of the units indicated in the choices for the ΔH of the reaction (kJ).

<u>4) Formula:</u>

  • ΔH reaction = Δ∑ ΔH products - ∑ ΔH reactants

<u>5) Solution:</u>

  • ΔH reaction = 4×ΔHCO₂ + 2×ΔH₂O - 2×ΔH C₂H₂ - 5 ΔH O₂

  • ΔH reaction = 4×(-393.5 kJ) + 2×(-241.8 kJ) - 2×(227.4 kJ) - 5×0

  • ΔH reaction = - 2,512.4 kJ ← answer
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Explanation:

Given:

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we can simply solve this by establishing and using a conversion factor of 1 ;

     

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21gallons x \frac{4qt}{1gal} x \frac{1 liter}{1.057qt} x \frac{1mL }{0.001L}  = 79470.2mL

we say;

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3 years ago
in the laboratory, a group of students was assigned to determine the density of an unknown liquid. They used a buret to find a v
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We drop all the digits after the zero.

The digit to be dropped is 7, so we <em>round up </em>the last significant figure of the answer.

1.10<u>7 843 137</u> → 1.11

4 0
4 years ago
When compounds form, which of the following statements is true about the elements that form them?
Greeley [361]

Answer:

C. Their properties change completely.

Explanation:

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For example, when solid magnesium burns in air, it forms both magnesium oxide and magnesium nitride, which are gases.

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4 years ago
In the SI system of units, the mole is one of seven base units. It is frequently used in chemical calculations. However, a mole
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We have to discuss here whether mole should be considered as a base unit in SI system or not.

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Mole is defined as the amount of substance that contains as many elementary entities as there are atoms in 0.012 kilogram of carbon-12. One mole contains exactly 6.022 X 10²³ elementary entities.

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5 0
3 years ago
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Aly's science class was looking at bacteria through a microscope. Aly's teacher said some bacteria can be as small as 0.00365 cm
olga nikolaevna [1]

Answer:

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Explanation:

Aly's teacher said some bacteria can be as small as 0.00365 cm long.

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In the given number, there are two zeroes before 3. We need to shift the decimal after 3. It can be done as follows :

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Hence, this is the required solution.

8 0
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