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natima [27]
3 years ago
11

The enthalpy of fusion of methanol (CH3OH) is 3.16 kJ/mol. How much heat would be absorbed or released upon freezing 25.6 grams

of methanol? 1. 2.52 kJ absorbed 2. 3.95 kJ absorbed 3. 0.253 kJ absorbed 4. 2.52 kJ released 5. 3.95 kJ released
Chemistry
1 answer:
Verdich [7]3 years ago
6 0

Answer:

There is  2.52 kJ of energy released (option 4)

Explanation:

Step 1: Data given

The enthalpy of fusion of methanol (CH3OH) is 3.16 kJ/mol

Mass of methanol = 25.6 grams

Molar mass of methanol = 32.04 g/mol

Step 2: Calculate moles of methanol

Moles methanol = mass methanol / molar mass methanol

Moles methanol = 25.6 grams / 32.04 g/mol

Moles methanol = 0.799 moles

Step 3: Calculate energy transfer

Energy  transfer = moles * enthalpy of fusion

Energy = 0.799 moles * 3.16 kJ/mol

Energy = 2.52 kJ released

There is  2.52 kJ of energy released

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A 100-watt light bulb radiates energy at a rate of 100 J/s. (The watt, a unit of power or energy over time, is defined as 1 J/s.
Semmy [17]

Answer

2.7956 * 10^19 photons

Givens

  • Wavelength = λ = 525 * 10^-9 meters  [1 nmeter = 1*10^-9 meters]
  • c = 3 * 10^8 meters
  • E = ???
  • W = 100  watts
  • t = 1 second
  • h= plank's Constant = 6.26 * 10^-34 J*s

Formula

E = h * c / λ

W = E / t

Solution

E = 6.26 * 10^-34 j*s * 3 * 10^8 m/s /525 * 10^-9 (m)

The meters cancel out. So do the seconds. You are left with Joules as you should be.

E =  3.577 * 10^-18 Joules

What you have found is the energy of 1 photon.

Now you have to find the Joules from the watts.

W = E/t

100 * 1 second = 100 joules

1 photon contains 3.577 * 10 ^ - 18 Joules

x photon = 100 joules                        

1/x = 3.577 * 10^-18 / 100                          Cross multiply

100 = 3.577 * 10 ^ - 18 * x                         Divide both sides by 3.577 * 10 ^ - 18

100/3.577 * 10 ^ - 18 = 3.577 * 10 ^ - 18x / 3.577 * 10 ^ - 18

2.7956 * 10^19 photons = x


7 0
3 years ago
How many molecules of water are released during the polymerization of a 20 monomer-long cellulose molecule?
Alborosie

Answer:

  • <em>During the polymerization of a 20 monomer-long cellulose molecule,</em> <u>19 molecules of water are released.</u>

<u></u>

Explanation:

In simple terms, <em>cellulose </em>is the biopolymer formed by many glucose units. This is cellulose is the polymer and glucose is the monomer.

To have a <em>20 monomer-long cellulose molecule</em>, 20 monomers have been chemically bonded by reacting 19 times, as it is explained in the next paragrpahs, and so 19 molecules of water have been released.

You can imaging the polymerization process as a step-by-step reaction in which the first step is the condensation reaction of one glucose molelecule to produce a 2 monomer-long chain, with the release of one molecule of water: the second step would be the condensation reaction between the 2 monomer-long chain with another glucose molecule, with the release of an additional molecule of water, and so on, until 19 condensation reactions happen, to obtain the 20 monomer-long cellulose molecule.

Condensation is the loss of water in a chemical reaction.

When two glucose molecules react together, condensation occurs. One OH group from each glucose molecule come together, the OH from one glucose molecule combines with the H part of the OH from the other glucose molecule, to form H₂O (water that is released).

The two glucose molecules (monomers) will form one bigger molecule where the two glucose monomers are bonded through the oxygen atom that did not form part of the water molecule released.

Then, a 20-monomer chain means 19 condenstation reactions, with the release of 19 molecules of water.

8 0
3 years ago
What is a single celled orginium able to do
vichka [17]
<span>Many life forms consist of a single cell. As well as simple bacteria, there are more complex organisms, known as protoctists. Unlike bacteria, they have complex internal structures, such as nuclei containing organized strands of genetic material called chromosomes. Most are single-celled, but some form colonies, with each cell usually remaining self-sufficient.</span>
4 0
3 years ago
As carbon dioxide enters systemic blood, it causes more oxygen to dissociate from hemoglobin, which in turn allows more CO2 to c
vagabundo [1.1K]

Answer:

The correct answer is "False".

Explanation:

It is false that as carbon dioxide enters systemic blood, it causes more oxygen to dissociate from hemoglobin. Once an atom of oxygen binds to hemoglobin, hemoglobin change its shape and makes easier than a second and a third atom of oxygen binds towards it. This change in conformation makes no possible that carbon dioxide can cause that oxygen dissociates from hemoglobin.

5 0
3 years ago
How many pounds does 1.00 quart of mercury weight? its density is 13.6g/mL
Gala2k [10]
Two steps by inspection 1 qt = 0.25 gallons, 13.6 g/mL = 13.6 kg/L

0.25 gallon x 3.785411784 L/gallon x 13.6 kg/L x 1 lb/0.45359237 kg = 28.374 lb.

Hope this Helps!
5 0
3 years ago
Read 2 more answers
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