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
ICE Princess25 [194]
3 years ago
14

Answer the following using the following information: ∆Hfus=6.02 kJ/mol; ∆Hvap= 40.7 kJ/mol; specific heat of water is 4.184 J/g

∙˚C; specific heat of ice is 2.06 J/g∙˚C; specific heat of water vapor is 2.03 J/g∙˚C.
A. How much heat is required to vaporize 25 g of water at 100˚C?

B. How much heat is required to convert 25 g of ice at -4.0 ˚C to water vapor at 105 ˚C (report your answer to three significant figures)?

C. An ice cube at 0.00 ˚C with a mass of 8.32 g is placed into 55 g of water, initially at 25 ˚C. If no heat is lost to the surroundings, what is the final temperature of the entire water sample after all the ice is melted (report your answer to three significant figures)?
Chemistry
1 answer:
OLga [1]3 years ago
8 0

Answer:

A. 56 kJ

B. 75.8 kJ

C. 11 ˚C

Explanation:

A. The heat of vaporization, ∆Hvap = 40.7 kJ/mol, gives the amount of energy per mole of water required to vaporize water to steam. The molar mass of water is 18.02 g/mol.

Q = M·∆Hvap = (25 g)(mol/18.02g)(40.7 kJ/mol) = 56 kJ

B. Five steps are necessary in this process. First, the ice will be warmed to 0 °C, then melted to water. The water will be heated to 100 °C, then vaporized. Finally, the vapor will be heated from 100 °C to 105 °C.

We calculate the heat required to warm the ice from -4.0 °C to 0 °C:

Q₁ = mcΔt = (25 g)(2.06 J∙g⁻¹˚C⁻¹)(0 °C - (-4.0 °C)) = 206 J

Then we calculate the heat required to melt the ice to water:

Q₂ = M∙∆Hfus = (25 g)(mol/18.02 g)(6.02 kJ/mol) = 8.35 kJ

Then, we calculate the heat required to warm the water from 0 °C to 100 °C.

Q₃ = mcΔt = (25 g)(4.184 J∙g⁻¹˚C⁻)(100 °C - 0 °C) = 10460 J

Then we calculate the heat required to vaporize the water:

Q₄ = M∙∆Hvap = (25 g)(mol/18.02 g)(40.7 kJ/mol)  = 56.5 kJ

Finally, the vapor is heated from 100 °C to 105 °C.

Q₅ = mcΔt = (25 g)(2.03 J∙g⁻¹˚C⁻)(105 °C - 100 °C) = 254 J

The total heat required is the sum of Q₁ through Q₅

Qtotal = Q₁ + Q₂ + Q₃ + Q₄ + Q₅

Qtotal = (206 J)(1 kJ/1000J) + 8.35 kJ + (10460 J)(1 kJ/1000J) + 56.5 kJ + (254 J)(1 kJ/1000J)

Qtotal = 75.8 kJ

C. The heat required to melt the ice is provided by the water as it decreases in temperature.  

First, we calculate the energy required to melt ice to water

Q = M∙∆Hfus = (8.32 g)(mol/18.02 g)(6.02 kJ/mol) = 2.779 kJ

There are at least two ways to solve this problem. Here, we will calculate the heat lost when all the water is brought to a temperature of 0 °C:

Q = mc∆t = (55 g)(4.184 J∙g⁻¹˚C⁻¹)(25 °C - 0°C) = 5753 J

We see that the water has enough energy to melt all of the ice. The residual heat energy of the water after melting all the ice is:

5753 J - (2.779 kJ)(1000J/kJ) = 2974 J

Now the problem becomes that we have (8.32 g + 55 g) = 63.32 g of water at 0 °C that will be raised to some final temperature by the residual heat of 2974 J:

Q = mcΔt ⇒ Δt = Q/(mc)

Δt = (2974 J) / (63.32 g)(4.184 J∙g⁻¹˚C⁻¹) = 11 ˚C

T(final) - T(inital) = 11 ˚C

T(final) = 11 ˚C + T(inital) = 11 ˚C + 0 ˚C  = 11 ˚C

Thus, the final temperature will be 11 ˚C.

You might be interested in
What is the Ka of a 0.0796 M solution of nitrous acid (HNO2) with a pH of 2.95?
Vadim26 [7]

Answer:

Coefficient = 1.58

Exponent = - 5

Explanation:

pH = 2.95

Molar concentration = 0.0796M

Ka = [H+]^2 / [HA]

Ka = [H+]^2 / 0.0796

Therefore ;

[H+] = 10^-2.95

[H+] = 0.0011220 = 1.122 × 10^-3

Ka = [H+] / molar concentration

Ka = [1.122 × 10^-3]^2 / 0.0796

Ka = (1.258884 × 10^-6) / 0.0796

Ka = 15.815 × 10^-6

Ka = 1.58 × 10^-5

Coefficient = 1.58

Exponent = - 5

4 0
3 years ago
Hydrogen boils at 20k. what is the boiling point of hydrogen on the celsius scale
Dimas [21]

Celsius scale is related to kelvin scale by the following equation,

⁰C = K-273

°C = K-273  

So as here temperature is given in kelvin, so it can be converted into celsius as follows:

So 20 K = 20K-273 °C  

= -253 °C .

So, the 20 K temperature equals to -253 °C.

So , -253 °C is equals to  20 K or 20 K temperature equals to -253 °C.

4 0
3 years ago
A proton is also known as this symbol, _____ ion.
mr Goodwill [35]
Hydrogen ion, strictly, the nucleus of a hydrogen atom separated from its accompanying electron. The hydrogen nucleus is made up of a particle carrying a unit positive electric charge, called a proton. The isolated hydrogen ion, represented by the symbol H+, is therefore customarily used to represent a proton.
4 0
3 years ago
Please need this ASAP. Calculate the mass of lime, CaO, that would be produced from 250 tonnes of limestone,
stiv31 [10]

Answer:

1.4×10⁸ g of CaO

Explanation:

We'll begin by converting 250 tonnes to grams (g). This can be obtained as follow:

1 tonne = 1×10⁶ g

Therefore,

250 tonne = 250 × 1×10⁶

250 tonne = 2.5×10⁸ g

Next, the balanced equation for the reaction.

CaCO₃ —> CaO + CO₂

Next, we shall determine the mass of CaCO₃ that decomposed and the mass CaO produced from the balanced equation. This can be obtained as follow:

Molar mass of CaCO₃ = 40 + 12 + (16×3)

= 40 + 12 + 48

= 100 g/mol

Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g

Molar mass of CaO = 40 + 16

= 56 g/mol

Mass of CaO from the balanced equation = 1 × 56 = 56 g

SUMMARY:

From the balanced equation above,

100 g of CaCO₃ decomposed to produce 56 g of CaO.

Finally, we shall determine the mass of CaO produced by the decomposition of 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃. This can be obtained as follow:

From the balanced equation above,

100 g of CaCO₃ decomposed to produce 56 g of CaO.

Therefore, 2.5×10⁸ g of CaCO₃ will decompose to produce =

(2.5×10⁸ × 56)/100 = 1.4×10⁸ g of CaO.

Thus, 1.4×10⁸ g of CaO will be obtained from 250 tonnes (i.e 2.5×10⁸ g) of CaCO₃.

6 0
3 years ago
Which are found in the retina?
Tom [10]
Your answer is D rods and cones. Hope this helps!! :) 
8 0
3 years ago
Read 2 more answers
Other questions:
  • Which of these phase changes does NOT involve changing a liquid into a gas?
    8·1 answer
  • On the Earth's surface, transporting materials are more common than residual materials. This condition is mainly the result of
    9·1 answer
  • Como um acido pode ser identificado?quais sao suas caracteristicas?
    12·1 answer
  • Write the correct formula for the ionic compound composed of magnesium and carbonate
    7·1 answer
  • What is the smallest particle of an element that has the chemical properties of that element
    10·1 answer
  • Tanks of compressed gas must be kept away from heat sources. If a compressed–gas tank is heated too much, it may explode and cau
    7·2 answers
  • What happens when carbon dioxide at 74 c is placed in thermal contact with water at 14 c
    8·1 answer
  • Ammonium acetate chemical formula
    15·2 answers
  • What is the atomic number and name of an element that has 15 protons in its nucleus?
    5·2 answers
  • Please answer quick
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!