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3 years ago

How is a forest fire considered a chemical change?

2 answers:

7 0

Wood and organic matter undergoes a combustion reaction with oxygen to create new compounds, such as water, carbon dioxide, and other species. Hope this helps you.. Good luck! (:

MArishka [77]3 years ago

3 0

A forest fire is considered a chemical change because of the changing of the wood by combustion, which is not a physical change.

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171 g of sucrose ( MW of 342, melting point 186 oC, boiling point very high, and vapor pressure is negligible) is dissolved in o

Fantom [35]

The complete question is as follows: 171 g of sucrose ( MW of 342, melting point 186 oC, boiling point very high, and vapor pressure is negligible) is dissolved in one liter of water at 25 oC. At 25 oC the vapor pressure of water is 24 mmHg. Which value is closest to the vapor pressure (VP) of this solution at 25 oC?

a. 16mm Hg

b. 24mm Hg

c. 20mm Hg

d. 12mm Hg

Answer: The vapor pressure (VP) of this solution at $25^{o}C$ is closest to the value 24 mm Hg.

Explanation:

Given: Mass of sucrose = 171 g

Mass of water = 1 L = 1000 g

Vapor pressure of water = 24 mm Hg

As moles is the mass of substance divided by its molar mass. Hence, moles of water (molar mass = 18.02 g) is calculated as follows.

$Moles = \frac{mass}{molar mass}\\= \frac{1000 g}{18.02 g/mol}\\= 55.49 mol$

Similarly, moles of sucrose (molar mass = 342 g/mol) is as follows.

$Moles = \frac{mass}{molar mass}\\= \frac{171 g}{342 g/mol}\\= 0.5 mol$

Total moles = 55.49 + 0.5 mol = 55.99 mol

Mole fraction of water is as follows.

$Mole fraction = \frac{moles of water}{total moles}\\= \frac{55.49}{55.99}\\= 0.99$

Formula used to calculate vapor pressure of the solution is as follows.

$P_{i} = P^{o}_{i} \times \chi_{i}$

where,

$P_{i}$ = vapor pressure of component i over the solution

$P^{o}_{i}$ = vapor pressure of pure component i

$\chi_{i}$ = mole fraction of i

Substitute the values into above formula to calculate vapor pressure of water as follows.

$P_{i} = P^{o}_{i} \times \chi_{i}\\= 24 mm Hg \times 0.99\\= 23.76 \\or 24 mm Hg\\$

Thus, we can conclude that the vapor pressure (VP) of this solution at $25^{o}C$ is closest to the value 24 mm Hg.

4 0

3 years ago

ENERGY CANNOT BE CREATED TRUE False Other:

Yuliya22 [10]

Answer:

its false ...............

8 0

4 years ago

Read 2 more answers

Calculate the mass of aluminum in 500 g of Al(C2H3O2)3

Luden [163]

Answer: 66.2 g

Explanation:

1) The ratio of Al in the molecule is 1 mol to 1 mol .

2) The mass of 1 mol of molecules of Al (CH2H3O2)3 is the molar mass of the compound.

3) You calculate the molar mass of the compound using the atomic masses of each atom, in this way:

Al: 27 g/mol
C: 2 * 3 * 12 g/mol = 72 g/mol
H: 3 * 3 * 1 g/mol = 9 g/mol
O: 2 * 3 * 16 g/mol = 96 g/mol

Molar mass = 27 g/mol + 72 g/mol + 9 g/mol + 96 g/mol = 204 g/mol

4) Set a proportion:

27 g/mol x
-------------------- = ----------
204 g/mol 500 g

5) Solve for x:

x = 500 g * 27 g/mol / 204 g/mol = 66.2 g

5 0

3 years ago

Which boiling point is lower an why?

DiKsa [7]

Answer:4

Explanation:

If we carefully observe the electronegativity of the elements in question

P-2.19

N-3.04

C-2.55

Si-1.9

H-2.2

SiH4 is definitely more polar than CH4 hence greater dipole forces of a higher boiling point. NH3 is more polar than PH3 hence NH3 has greater dipole forces and a higher boiling point. Electronegative differences influences the polarity of a bond. The greater the electro negativity difference between bonding atoms, the greater the dipole forces and the greater the boiling point.

3 0

4 years ago

Read 2 more answers

Q05 the "atomic number" of an atom is determined by the number of ________ it has.

Alexxx [7]

The atomic number of an atom is determined by the number of protons it has..

It is also the whole number shown on the periodic table

6 0

4 years ago