1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
skelet666 [1.2K]
3 years ago
6

State hess's law.how is it used

Chemistry
2 answers:
Vesnalui [34]3 years ago
5 0
 <span>Hess' Law states that the enthalpy change in a reaction can be calculated from the enthalpy changes of reactions that, when combined, result in the desired reaction. 

For example, to check the enthalpy change that occurs when benzene undergoes incomplete combustion to water and carbon monoxide is not an easy task, because the products invariably contain CO2. However, by combining the reactions of the complete combustion of benzene and the combustion of CO, you can get the reaction you want. 

Reaction wanted: 2C6H6 + 9O2 → 12CO + 6H2O 
Reactions provided: 2C6H6 + 15O2 → 12CO2 + 6H2O and 2CO + O2 → 2CO2, and their associated ΔH. 

Rearrange the reactions so that, when they add up, they result in the wanted reaction. 

2C6H6 + 15O2 → 12CO2 + 6H2O (leave as is; no changes to ΔH) 
12CO2 → 12CO + 6O2 (reverse and multiply by 6; this changes the sign of ΔH and multiplies it by 6) 

Added up, it will result in 2C6H6 + 9O2 → 12CO + 6H2O. Add up the ΔH values for the rearranged reactions to find ΔH for this particular reaction.</span>
PSYCHO15rus [73]3 years ago
5 0

Answer: Hess's Law says the total enthalpy change does not rely on the path taken from beginning to end. Enthalpy can be calculated in one grand step or multiple smaller steps.

To solve this type of problem, organize the given chemical reactions where the total effect yields the reaction needed. There are a few rules that you must follow when manipulating a reaction.

The reaction can be reversed. This will change the sign of ΔHf.

The reaction can be multiplied by a constant. The value of ΔHf must be multiplied by the same constant.

Any combination of the first two rules may be used.

Finding a correct path is different for each Hess's Law problem and may require some trial and error.

You might be interested in
What are the reactants and products when butane combusts with excess oxygen?
larisa86 [58]
C3H8 + O2 --> CO2(g) + H2O(g) + energy(heat)

butane + oxygen --> carbon dioxide + water + heat 
7 0
3 years ago
Tara predicts the number of paper clips attracted by the magnet
muminat

The responding variable refers to the variable that changes as the independent variable is being manipulated. In this case, the responding variable is the number of paper clips attracted by the magnet.

An experiment must include a dependent (responding) variable and an independent variable. As the independent variable is manipulated during the experiment, the dependent (responding) variable changes accordingly.

In this case; the independent variable is temperature while the dependent (responding) variable is the number of paper clips attracted by the magnet.

Learn more: brainly.com/question/967776

7 0
3 years ago
What kind of liquid promote corrosion
MaRussiya [10]
Is this the whole answer?
7 0
3 years ago
In the context of small molecules with similar molar masses, arrange these intermolecular forces by strength (hydrogen bonding -
Katarina [22]
<h2>Answer:</h2>

Arrangement of inter molecular forces from strongest to weakest.

  • Hydrogen bonding
  • Dipole-dipole interactions
  • London dispersion forces.
<h3>Explanation:</h3>

Intermolecular forces are defined as the attractive forces between two molecules due to some polar sides of molecules. They can be between nonpolar molecules.

Hydrogen bonding is a type of dipole dipole interaction between the positive charge hydrogen ion and the slightly negative pole of a molecule. For example H---O bonding between water molecules.

Dipole dipole interactions are also attractive interactions between the slightly positive head of one molecule and the negative pole of other molecules.

But they are weaker than hydrogen bonding.

London dispersion forces are temporary interactions caused due to electronic dispersion in atoms of two molecules placed together. They are usually in nonpolar molecules like F2, I2. they are weakest interactions.

5 0
3 years ago
How does the law of conservation of mass apply to this reaction C2H4+4O2--&gt;4H2O+2CO2 .Only the oxygen needs to be balanced B.
r-ruslan [8.4K]
C2H4+4O2-->4H2O+2CO2

the answer is C
6 0
3 years ago
Read 2 more answers
Other questions:
  • A temperature of 20 degrees C is equivalent to approximately
    5·2 answers
  • How does our understanding of genetics influence psychological research
    15·1 answer
  • Which of the following is one way that nuclear reactions differ from chemical<br> reactions?
    7·1 answer
  • Calculate the solubility of cux(ksp=[cu2 ][x2?]=1.27×10?36 in a solution that is 0.120 m in nacn.
    5·1 answer
  • What is the purpose of strawberry seeds
    6·1 answer
  • Calculate the percent saturated fat in the total fat in butter
    14·1 answer
  • Who else just copy and pastes the questions from edge?
    9·1 answer
  • Which series reveals the source of energy for oil? please help ASAP!!! WILL MARK BRAINLEST
    6·2 answers
  • How do you use the periodic table to determine the mass of 4 moles of oxygen? Explain your process for getting the answer. Use s
    14·2 answers
  • How many grams of water will be produced when 14.9 L of H2 reacts according to the following equation?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!