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
stepladder [879]
3 years ago
9

A 35.6 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature ros

e from 35.0 to 76.0°C and the heat capacity of the calorimeter is
23.3 kJ/°C, what is the value of DH°rxn? The molar mass of ethanol is 46.07 g/mol.

C2H5OH(l) + O2(g) → CO2(g) + H2O(g) ΔH°rxn = ? (Points : 1)
-1.24 × 103 kJ/mol
+1.24 × 103 kJ/mol
-8.09 × 103 kJ/mol
-9.55 × 103 kJ/mol
+9.55 × 103 kJ/mol
Chemistry
1 answer:
PilotLPTM [1.2K]3 years ago
7 0
<h3>Answer:</h3>

1.24 × 10³ kJ/mol

<h3>Explanation:</h3>

From the question we are given;

Heat capacity of the calorimeter =23.3 kJ/°C

Temperature change, ΔT = 76°C - 35°C

                                          =  41 °C

Mass of ethanol = 35.6 g

Molar mass of ethanol = 46.07 g/mol

We are required to determine the molar enthalpy

We can use the following steps:

<h3> Step 1 : Calculate the heat change of the reaction</h3>

Heat change will be equivalent to heat gained by the calorimeter.

Therefore;

Heat = heat capacity × change in temperature

Q = CΔT

   =  23.33 kJ/°C × 41°C

   = 955.3 kJ

<h3>Step 2 : Calculate the moles of ethanol burned </h3>

Moles = mass ÷ Molar mass

Therefore;

Moles of ethanol = 35.6 g ÷ 46.07 g/mol

                            = 0.773 moles

<h3>Step 3: Calculate the molar enthalpy of the reaction </h3>

Heat change for 0.773 moles of ethanol is 955.3 kJ

0.773 moles = 955.3 kJ

1 mole will have ,

    = 955.3 kJ ÷ 0.773 moles

    = 1235.83 kJ/mol

    = 1.24 × 10³ kJ/mol

But since the reaction is exothermic (release of heat) then the enthalpy change will have a negative sign.

Thus;

ΔH = -1.24 × 10³ kJ/mol

You might be interested in
What does the second law of thermodynamics say about entropy
alukav5142 [94]

Answer:

The entropy and the systems surrounding it tend to increase.

5 0
2 years ago
Read 2 more answers
5. Inside the mouth, these cells are joined together in a sheet. Why are they scattered here?
anyanavicka [17]

Answer:

Inside the mouth, these cells are joined together in a sheet. Why are they scattered here? They are scattered here because we disrupted there original form by scrapping them off our mouths and smearing them on the slide.

Explanation:

5 0
3 years ago
How many particles are present in 8.0 moles of silver?
Zielflug [23.3K]

Answer:the answer is b

Explanation:I took the test and got it right

3 0
2 years ago
What do two or more atoms form when they share electrons in a chemical bond
dlinn [17]
A covalent bond is your answer
6 0
3 years ago
Read 2 more answers
A 4.24 kg marble slab has the volume of 1564 cm3 What is the density in g/cm3
miskamm [114]

Answer:

The answer is

<h2>2.71 g/cm³</h2>

Explanation:

The density of a substance can be found by using the formula

density =  \frac{mass}{volume} \\

From the question

volume of marble = 1564 cm³

1 kg = 1000 g

4.24 kg = 4240 g

mass = 4240 g

The density is

density =  \frac{4240}{1564}   \\  = 2.710997442...

We have the final answer as

<h3>2.71 g/cm³</h3>

Hope this helps you

7 0
2 years ago
Other questions:
  • A librarian is interested in the numbers of books that visitors check out from the library. She examines the checkout records of
    6·2 answers
  • What are the characteristics shapes of s p and d orbitals
    11·1 answer
  • Volaic cells produce a positive overall charge what does this indicate
    12·1 answer
  • Which human activity would most likely decrease the amount of carbon in the atmosphere?
    8·2 answers
  • What compotent of air is least nessasery for life on earth
    12·1 answer
  • Which climate prevails in the northwest coast of the United States?
    11·2 answers
  • What two forces act in the nucleus to create a 'nuclear tug-of-war'?
    7·1 answer
  • The gases in the can of compressed air are at the temperature of 298.3 K and a pressure of 270.3. If the gases in the can reach
    10·2 answers
  • All atoms of a given element must contain the same number of
    6·1 answer
  • What should be done in order to increase the gravitational force between two objects?
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!