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
36.8 g of CuSO4(s) was added to water to prepare a 2.00 L solution. What is the
Yuki888 [10]

Answer:

Option D. 0.115 M

Explanation:

The following data were obtained from the question:

Mass of CuSO4 = 36.8 g

Volume of solution = 2 L

Molar mass of CuSO4 = 159.62 g/mol

Molarity of CuSO4 =..?

Next, we shall determine the number of mole in 36.8 g of CuSO4.

This can be obtained as shown below:

Mass of CuSO4 = 36.8 g

Molar mass of CuSO4 = 159.62 g/mol

Mole of CuSO4 =.?

Mole = mass /Molar mass

Mole of CuSO4 = 36.8 / 159.62

Mole of CuSO4 = 0.23 mole

Finally, we shall determine the molarity of the CuSO4 solution as illustrated below:

Mole of CuSO4 = 0.23 mole

Volume of solution = 2 L

Molarity of CuSO4 =..?

Molarity = mole /Volume

Molarity of CuSO4 = 0.23 / 2

Molarity of CuSO4 = 0.115 M

Therefore, the molarity of the CuSO4 solution is 0.115 M.

5 0
3 years ago
Nitric oxide, an important pollutant in air, is formed from the elements nitrogen and oxygen at high temperatures, such as those
Tanya [424]

Answer:

Q is 0.5 and K is 0.01, therefore K is less than Q.

the system will proceed in the reverse direction, thereby converting products into reactants. converting Nitric oxide to form oxygen and nitrogen.

Explanation:

Given,

N2 (g) + O2 (g) « 2 NO (g)

K = 0.01

heated temperature = 2000 ⁰C

N2 moles =0.4

O2 moles =0.1

2NO moles = 0.08

Volume of container = 1L

Q is the reaction quotient  of the equilibrium equation. it is use to determined which direction the system will move to by comparing it with the K value.

Q can be calculated by multiplication of mass of reactant divide by mass of product

Q =\frac{ [N2] *[O2}{2NO}

the mass of the chemicals are in mole, there is need to convert them to moles/litre

therefore,

for N₂ : 0.4 mole per 1L container = 0.4 mol/L = 0.4M

for O₂ : 0.1 mole per 1L container = 0.1 mol/L = 0.1M

for 2NO : 0.08mole per 1L container = 0.08 mol/L = 0.08M

Q =\frac{ [N2] *[O2}{2NO} = (0.4*0.1)/0.08 = 0.5

finally, we are going to compare the value of Q with K

Note that:

if K>Q , the reaction will proceed forward, converting reactants into product.

if K<Q , the reaction will proceed backward, converting products into reactants.

if K=Q , the system of reaction is already in equilibrium.

since, Q is 0.5 and K is 0.01, therefore K is less than Q.

the system will proceed in the reverse direction, thereby converting products into reactants. converting Nitric oxide to form oxygen and nitrogen.

7 0
3 years ago
Which two functional groups are always found in amino acids?
Dmitry_Shevchenko [17]
The answer would be the amino group and the carboxyl group
hope this helpssss
6 0
3 years ago
How to do balance chemical equiations
alex41 [277]
Hey, lovely! It's a pretty lengthy process but here is a pretty clear video on how to do it. Hope this helps ya!

https://www.khanacademy.org/science/chemistry/chemical-reactions-stoichiome/balancing-chemical-equat...

4 0
3 years ago
Question 2Classify the following organic structures:CH3OCH3CH2CH2CHCH2CH3CH3NHCH3CH3CH(OH)CH₂CH3
Naily [24]

Within the options, we have four organic compounds. Let's see what the skeletal structure of the compounds is in order to identify them better:

The first compound CH3OCH3 has two methyl groups linked by a carbon atom, this type of compound is called an Ether

The second compound has a double bond, it is badly written but it seems that is an alkene.

The third compound has two methyl groups linked by nitrogen atoms, therefore will be an amine.

The last compound has a hydroxyl group, therefore it is an alcohol

Answer:

CH3OCH3 Ether

CH2CH2CHCH2CH3 Alkene

CH3NHCH3 Amine

CH3CH(OH)CH₂CH3 Alcohol

3 0
1 year ago
Other questions:
  • How to find the oxidation number of an element
    14·1 answer
  • A student is using the periodic table to find information for a report on elements. One of the statements about fluorine in her
    13·1 answer
  • What is the pH of a solution prepared by mixing 25.00 mL of 0.10 M CH3CO2H with 25.00 mL of 0.010 M CH3CO2Na? Assume that the vo
    8·1 answer
  • How is electrical energy used?
    10·2 answers
  • So our professor didn't go over this but is freshly cut sodium, but rapidly tarnishes on contact with air a physical or chemical
    14·1 answer
  • Consider the reaction. X ( g ) + Y ( g ) − ⇀ ↽ − Z ( g ) K p = 1.00 at 300 K In which direction will the net reaction proceed fo
    13·1 answer
  • Please help<br><br> What causes a wave to have a higher amplitude?
    14·2 answers
  • Helppppppp meeeeeeeeeeeee
    11·2 answers
  • True or false condensation occurs when liquid is converted to a solid
    13·2 answers
  • What is the difference between physics and chemistry laboratory (4)
    15·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!