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dezoksy [38]
2 years ago
8

water has a specific heat of 4.18 j/gK and a molar heat of vaporization of 40.7 kJ. Calculate the minimum amount of heat necessa

ry to vaporize 90 g of water starting at 20 c
Chemistry
1 answer:
Marrrta [24]2 years ago
5 0

Answer:

To calculate the minimum amount of heat necessary to vaporize 90 g of water starting at 20 c

Explanation:

We will use heat balance equation

Q = q1+q2 = mCΔt + nL

where

m = mass of water = 90g

C = specifi heat of water =4.18J/gK

L = Latent heat of Vaporization = 40.7kJ/mol

Δt = temperature changes = 100 - 20 = 80 degree

water at 20 degrees to water at 100 degrees

then water at 100 degrees to vapor at 100 degrees

q1 = (90g)(4.18J/gK)(80K)

q1 = 30096J=30.1kJ

But

m =90 g water, gives  n = 5mol water (divide by his molar mass which is 18g)

q2=nL= (40.7kJ/mol)(5mol)

q2=203.5kJ

the minimum amount of heat necessary to vaporize 90 g of water starting at 20 c = q1+q2 =30.1+203.5=233.6kJ

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Explanation:

The pH scale measures how acidic an object is. Objects that are not very acidic are called basic. The scale has values ranging from zero (the most acidic) to 14 (the most basic). As you can see from the pH scale above, pure water has a pH value of 7. This value is considered neutral—neither acidic or basic. Normal, clean rain has a pH value of between 5.0 and 5.5, which is slightly acidic. However, when rain combines with sulfur dioxide or nitrogen oxides—produced from power plants and automobiles—the rain becomes much more acidic. Typical acid rain has a pH value of 4.0. A decrease in pH values from 5.0 to 4.0 means that the acidity is 10 times greater.

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There are many high-tech devices that are used to measure pH in laboratories. One easy way that you can measure pH is with a strip of litmus paper. When you touch a strip of litmus paper to something, the paper changes color depending on whether the substance is acidic or basic. If the paper turns red, the substance is acidic, and if it turns blue, the substance is basic

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3 years ago
What is the percent composition by mass of hydrogen in nh4hco3
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<u>Answer:</u> The percent composition by mass of hydrogen in given compound is 6.33 %

<u>Explanation:</u>

We are given:

A chemical compound having chemical formula of NH_4HCO_3

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To calculate the percentage composition by mass of hydrogen in the compound, we use the equation:

\%\text{ composition of Hydrogen}=\frac{\text{Mass of hydrogen}}{\text{Mass of compound}}\times 100

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Mass of hydrogen = (5\times 1)=5g/mol

Putting values in above equation, we get:

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6 0
3 years ago
Catalyst
Hoochie [10]

a. volume of NO : 41.785 L

b. mass of H2O : 18 g

c. volume of O2 : 9.52 L

<h3>Further explanation</h3>

Given

Reaction

4 NH₃ (g) + 5 O2 (g) → 4 NO (g) + 6 H2O (l)

Required

a. volume of NO

b. mass of H2O

c. volume of O2

Solution

Assume reactants at STP(0 C, 1 atm)

Products at 1000 C (1273 K)and 1 atm

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