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2 years ago

Which fact about fuel cells is FALSE?

Chemistry

1 answer:

soldier1979 [14.2K]2 years ago

5 0

Answer: Option (d) is the correct answer.

Explanation:

An electrochemical cell with the help of which chemical energy of a fuel (generally hydrogen) and an oxidizing agent (generally oxygen) are converted into electrical energy by a pair of redox reactions.

A fuel cell is able to generate electricity as long as fuel and oxygen are supplied to it.

As, hydrogen and oxygen are generally used as a fuel so, this results in the formation of water as a by-product.

Thus, we can conclude that the statement fuel cell automobiles are powered by water and the only emission is hydrogen, is FALSE about fuel cells.

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A 500.0 g block of dry ice (solid CO2, molar mass = 44.0 g) vaporizes at room temperature. Calculate the volume of gas produced

Damm [24]

Considering the ideal gas law, the volume of gas produced at 25.0 °C and 1.50 atm is 184.899 L.

<h3>Definition of ideal gas</h3>

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

<h3>Ideal gas law</h3>

An ideal gas is characterized by absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of gases:

P×V = n×R×T

<h3>Volume of gas</h3>

In this case, you know:

P= 1.50 atm
V= ?
n= 500 g× $\frac{1 mole}{44 g}$ = 11.36 moles, being 44 $\frac{g}{mole}$ the molar mass of CO₂
R= 0.082 $\frac{atmL}{molK}$
T= 25 C= 298 K (being 0 C=273 K)

Replacing in the ideal gas law:

1.50 atm×V = 11.36 moles×0.082 $\frac{atmL}{molK}$ × 298 K

Solving:

V= (11.36 moles×0.082 $\frac{atmL}{molK}$ × 298 K) ÷ 1.50 atm

Finally, the volume of gas produced at 25.0 °C and 1.50 atm is 184.899 L.

Learn more about the ideal gas law:

<u>brainly.com/question/4147359?referrer=searchResults</u>

4 0

2 years ago

HELPPPPPPPPPPPPPPPPPPPPPPPP MEEHHHHHHHHHHHHHH

AnnZ [28]

Here you are looking on the Free Body diagram of a net force of 0N in both the x and y-directions. the only ones that has that condition met is A and C.

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3 years ago

Which part of the atom is directly involved in chemical changes? A. the electron B. the energy levels C. the nucleus D. the char

7nadin3 [17]

The part of the atom that is involved in chemical changes is A. electron. The electrons that are in the most outer shells are called valence electrons which are easily removed or shared to form bonds. Valence electrons are related to the number of valence electrons

8 0

3 years ago

Phenolphthalein has a pKa of 9.7 and is colorless in its acid form and pink in its basic form. calculate [In-}/{HIn} for the fol

zvonat [6]

Answer:

1.58x10⁻⁵

2.51x10⁻⁸

0.0126

63.10

Explanation:

Phenolphthalein acts like a weak acid, so in aqueous solution, it has an acid form HIn, and the conjugate base In-, and the pH of it can be calculated by the Handerson-Halsebach equation:

pH = pKa + log[In-]/[HIn]

pKa = -logKa, and Ka is the equilibrium constant of the dissociation of the acid. [X] is the concentrantion of X. Thus,

i) pH = 4.9

4.9 = 9.7 + log[In-]/[HIn]

log[In-]/[HIn] = - 4.8

[In-]/[HIn] = $10^{-4.8}$