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
professor190 [17]
3 years ago
8

Ethanol (c2h5oh) melts at -114°c. the enthalpy of fusion is 5.02 kj/mol. the specific heats of solid and liquid ethanol are 0.9

7 j/gk and 2.3 j/gk, respectively. how much heat (kj) is needed to convert 25.0 g of solid ethanol at -135°c to liquid ethanol at -50°c?
Chemistry
1 answer:
Nimfa-mama [501]3 years ago
6 0

Answer: 4.18925 kJ heat is needed to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.

Explanation:

Temperature of Solid C_2H_5OH=-135^oC=138 K(0^oC=273K)

Melting temperature of Solid C_2H_5OH=114^oC=159 K

Temperature of liquid C_2H_5OH=-50^oC=223K

Specific heats of solid  ethanol = 0.97 J/gK

Specific heats of liquid ethanol = 2.3 J/gK

Heat required to melt the the 25 g solid C_2H_5OH at 159 K

\Delta T_1 = 159 K - 138 K = 21 K

Q_1=mc\Delta T= 25\times 0.97J/gK\times 21 K=509.25 J

Heat required to melt and raise the temperature of C_2H_5OH upto 223 K

\Delta T_2 = 223 K - 159 K  = 64 K

Q_2=mc\Delta T= 25\times 2.3J/gK\times 64 K=3680 J

Total heat to convert solid ethanol to liquid ethanol at given temperature :

Q_1+Q_2=509.25 J+3680 J=4189.25 J=4.18925 kJ (1kJ=1000J)

Hence, 4.18925 kJ of heat will be required to convert 25.0 g of solid ethanol at -135 °C to liquid ethanol at -50°C.

You might be interested in
Describe how you would separate rock salt to obtain salt crystals and pure dry sand.
USPshnik [31]

Answer:

Separating Sand and Salt

Probably the easiest method to separate the two substances is to dissolve salt in water, pour the liquid away from the sand, and then evaporate the water to recover the salt.

6 0
3 years ago
Read 2 more answers
What is the correct name for CaS04? (a) calcium sulfoxide (b) calcium sulfite (c) calcium sulfur oxide (d) calcium sulfate (e) c
Zielflug [23.3K]

Answer: OPTION, D

Explanation:

It is an example for ionic salt and has Calcium ion and sulfate ion.

Hence it's name is Calcium sulfate.

Calcium sulfoxide does not exist.

Calcium sulfite has CaSO3.

5 0
3 years ago
Read 2 more answers
what is the suggested weight of the sample that should be disssolved in the beaker before it is transferred to the NMR tube
sukhopar [10]
The sample must be sufficiently soluble (fig. 2) to yield an NMR spectrum. For 1H and 1H observed NMR, it is recommended to dissolve between 2 and 10 mg in between 0.6 and 1 mL of solvent so that the sample depth is at least 4.5 cm in the tube (fig. 3).
3 0
2 years ago
What phase(s) would you expect to observe when the substance is at a temperature of 275 kelvin?
pychu [463]
The phase of a substance at a temperature of 275 K or 1.85 degrees Celsius can be any of the three phases namely a solid, a liquid and a gas. This depends on the pressure where the substance is subjected. Also, the phase can be determined by a phase diagram where it shows the phase of a certain substance at a specific temperature and pressure.
4 0
3 years ago
In preparation for a demonstration, your professor brings a 1.50−L bottle of sulfur dioxide into the lecture hall before class t
solmaris [256]

Answer:

4.81 moles

Explanation:

The total pressure of the gas = Pressure at which gauge reads zero + pressure read by it.

Pressure at which gauge reads zero = 14.7 psi

Pressure read by the gauge = 988 psi

Total pressure = 14.7 + 988 psi = 1002.7 psi

Also, P (psi) = P (atm) / 14.696

Pressure = 1002.7 / 14.696  = 68.2297 atm

Temperature = 25 °C

The conversion of T( °C) to T(K) is shown below:

T(K) = T( °C) + 273.15  

So,  

T = (25 + 273.15) K = 298.15 K  

Volume = 1.50 L

Using ideal gas equation as:

PV=nRT

where,  

P is the pressure

V is the volume

n is the number of moles

T is the temperature  

R is Gas constant having value = 0.0821 L.atm/K.mol

Applying the equation as:

68.2297 atm × 1.5 L = n × 0.0821 L.atm/K.mol × 298.15 K  

⇒n = 4.81 moles

4 0
3 years ago
Other questions:
  • Determine the mass in grams of each of the following:
    8·1 answer
  • What’s the percent composition of each element in strontium carbonate.
    14·2 answers
  • A student compares the booking point of substances having different intermolecular forces. Which independent variable did the st
    6·1 answer
  • ASAP PLEASE, 25 POINTS!
    11·2 answers
  • Camphor (C10H16O) melts at 179.8°C, and it has a particularly large freezing-point-depression constant, Kf= 40.0ºC/m. When 0.186
    11·2 answers
  • Which statement best describes what the volume of an object represents
    7·1 answer
  • What is titanium's melting point?
    6·1 answer
  • Describe the experiment to prove Ohm's law ​
    5·2 answers
  • Select the correct answer<br><br> Giving brainliest
    14·1 answer
  • The sun is bigger than the Moon, but they appear to be the same size in the sky when you look at them from Earth. Why?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!