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2 years ago

How much heat is lost when changing 65 g of water vapor (H2O) at 421 K to ice at 139 K?

Chemistry

1 answer:

poizon [28]2 years ago

3 0

The heat change will be

Moles of water = mass / Molar mass = 65/ 18 = 3.61 mol

specific heat of ice =2.09J /g C

specific heat of water = 4.184 J/g C

Specific heat of vapour= 2.01 /g C

Heat of fusion = 3.33X10⁵ J /kg = 333 J /g

Heat of vaporization = 2.26 X10⁶J/kg = 2260J/g

Q1 = heat change when vapours get cooled to 373.15 K

Q2 = heat change when vapours get converted to liquid water

Q3 = heat change when liquid water cools to 273.15 K

Q4= heat change when liquid water freezes to ice

Q5= heat change when ice cools from 273.15K to 139 K

Q1= mass of water X specific heat of vapours X change in temperature

Q1 = 65 X 2.01 /g C X (421-373.15) = 6251.60 J = 6.252 kJ

Q2 = heat of vaporization X mass = 2260 X 65 = 146900 = 146.9 kJ

Q3 = mass X specific heat of water X change in temperature =

Q3 = 65 X 4.184 X (373.15-273.15) = 65 X 4.184 X 100 = 27196 J = 27.196kJ

Q4 = heat of fusion X mass =333X65 = 21645 J = 21.645 kJ

Q5 = mass X specific heat of ice X change in temperature

Q5 = 65 X 2.09 X (273.15-139) = 18224.3 J = 18.224 kJ

Total energy = 6.252 +146.9+27.196+ 21.645+ 18.224 = 220.217

As this is energy released so it will be expressed in negative

-220.217

from the given options the correct answer will be -219.4 kJ

The answer is little different as the reference values of specific heats or enthalpy may vary.

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2 years ago

In which 1.0 gram sample are particles arranged in a rystal structure?

lilavasa [31]

The Options are as follow,

Answer:

Option-1 is the correct answer.

Explanation:

As we know crystal formation is the property of solids. Therefore, in given options we are given with four different states of matter.

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Option 2, C₂H₆ (Ethane) is in gas form, so it cannot form crystals.

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2 years ago

Solve without using a calculator. Substance ab2 is 60.0% a by mass. What is the percent a by mass for substance ab?

Orlov [11]

The percent A by mass for substance AB =<u> 75%</u>

<h3>Further explanation</h3>

Proust states the Comparative Law that compounds are formed from elements with the same Mass Comparison, so that compounds have a fixed composition of elements

Empirical formula is the mole ratio of compounds forming elements.

From Substance AB₂ is 60.0% A by mass.

Let's say that AB₂ mass = 100 gram, then

mass A = 60 gram

mass B = 40 gram : 2 (coefficient in compound AB₂ = 2) = 20 gram

In compound AB:

Total mass = mass A + mass B

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<h3>Learn more</h3>

Grams of KO₂ needed to form O₂

brainly.com/question/2823257

Keywords : percent mass, substance

#LearnwithBrainly

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2 years ago

The dissociation of calcium carbonate has an equilibrium constant of Kp = 1.16 at 1073 K . CaCO3(s) ⇄ CaO(s) + CO2(g) If you pla

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Answer:

<h3> $Pressure of CO_2 in the container=1.6 atm$ </h3>

Explanation:

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two components are solid so these two will not exert any kind of pressure in the container so at equilibrium only CO2 will apply pressure on the container

Therefore only partial pressure of CO2 will be taken for the calculation of equilibrium pressure constant i.e. Kp

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$K_p=p$

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2 years ago

What is the mass of 0.921 moles of sulfur dioxide gas (SO2)?

Serhud [2]

Answer:

mass = 58.944 g

Explanation:

Given data:

Number of moles of SO₂ = 0.921 mol

Mass of SO₂ = ?

Solution:

Formula:

Number of moles = mass/ molar mass

First of all we will calculate the molar mass.

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Now we will put the values in formula.

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mass = 0.921 mol × 64 g/mol

mass = 58.944 g

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2 years ago