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
Akimi4 [234]
3 years ago
5

A 0.1018 g sample of organic compound with a molar mass of 225.4 g/mol was

Chemistry
1 answer:
Vlada [557]3 years ago
5 0

Answer:

Q = -17,200 Kj/mole = -1.72 x 10⁴ Kj/mol

Explanation:

Calorimeter Equation => Q = Cv·ΔT

For the <u>0.1018 gram sample</u> of organic compound burned in calorimeter ...

Cv = calorimeter heat capacity at constant volume = 2.95 Kj/K (Cv is typically supplied by manufacturer of the calorimeter as a standard for the instrument).

ΔT = temperature change experienced by calorimeter water in Kelvin (K)  values = +2.63 K (NOTE => increasing (+) temp indicates heat flow from sample to calorimeter water => Exothermic Rxn).

<u>Q(for 0.1018g sample)</u> = (2.95 Kj/K)(2.63 K) = 7.7585 Kj          

Converting to Kj/mole => divide the sample heat value (7.7585 Kj) by moles of sample used => moles of sample = mass/molar mass.

<u>Moles of Organic Sample</u> = 0.1018g/225.4g·mol⁻¹ = 4.52x10⁻⁴ mole

∴ Q(kj/mole) = Q/n = 7.7585 Kj/4.52x10⁻⁴mole = 1.72x10⁴ Kj/mole (exothermic)*

*Why 'exothermic'? => Since the reaction was carried out in a bomb calorimeter the energy flow of the reaction is measured in terms of a temperature change. The problem dialogue indicates <em>'increased' </em>temp. by 2.63 K. This indicates the sample, upon burning, was <u>releasing heat energy</u> into the surroundings. That is, the heat flow is toward the water jacket of calorimeter and away from the sample thereby heating the water and showing an increase in temperature. This type of heat flow is 'exothermic' with respect to the system sample and it's energy value is posted with a 'negative' sign to indicate heat loss during process. Therefore, the molar heat of combustion = -17,200 Kj/mole.  

           

NOTE: Endothermic Reactions

For a notation in problems that the temperature measurement is discribed as <u><em>decreased</em></u> would indicate an endothermic reaction - heat flow from surroundings toward sample of interest. In such a case, a plus (+) signage should accompany the Q-value calculated. <em>However, the problem in this post is 'exothermic' and should be accompanied by a negative (-) signage.</em>

<em />

You might be interested in
In atoms, electrons surround the nucleus in?
Charra [1.4K]

either the answer is  B or D

4 0
3 years ago
Read 2 more answers
Carbonic acid dissolves limestone and other rocks. This is an example of _____. chemical errosion
Jet001 [13]

Carbonic acid dissolves limestone and other rocks. This is an example of chemical erosion. An example is in the caves. Caves are formed where rainwater as it falls through the atmosphere absorbs carbon dioxide. The carbon dioxide makes the rain acidic to react it with the limestone bedrock. The rainwater is absorbed by the soil into the ground. Then as it enters through the soil, the rainwater will absorb more carbon dioxide that is produced by the decomposers. The carbon dioxide with water reacts to form carbonic acid. The carbonic acid will react to limestone and dissolves it slowly. As the space become larger, water can enter into it.

8 0
3 years ago
What type of hybridization is needed to explain why ethyne, C2H2, is linear?
Dmitrij [34]

When C-C is having a triple bond the hybridization is sp. But I am not sure how to relate that to the linear shape.

5 0
3 years ago
if the density of a bar of gold is 19.3g/cm^3and you cut it into four pieces , what is its density of each piece of gold
AlladinOne [14]
Density is an intrinsic property, so it is independent of the amount of substance present: one gold coin would have the same density as a solid gold boulder.

So if the density of gold is 19.3 g/cm³, the density of a bar of gold and the pieces into which the bar is cut would all be 19.3 g/cm³.
4 0
3 years ago
I need help ASAP!!!!! What happens to water when it changes to ice?
Gre4nikov [31]

- It's density increases

- mass increases

- volume increases

Hope this helps!

6 0
2 years ago
Read 2 more answers
Other questions:
  • Which of the following was a cause of the French and Indian War?
    10·2 answers
  • How do I fill this table?​
    9·1 answer
  • Which one goes first
    8·2 answers
  • Pls help! I’m not very smart so please explain it to me!
    9·2 answers
  • How many bonds does Potassium Iodide have?
    9·1 answer
  • Which of the following diagrams illustrates a series circuit with two resistors?
    5·1 answer
  • Dan wants to test the effects of different amounts of antibiotic on bacteria. While setting up his experiment he makes sure to u
    12·1 answer
  • Hayley woke up to a hot and humid day but knows it is going to cool off later. What should she expect the weather to be like ton
    9·2 answers
  • How do mosses and ferns reproduce?
    9·1 answer
  • Aluminum can be used to make soft drink cans because of which property?
    7·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!