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2 years ago

Which statements about fresh-water sources are true.? (Multiple Choice) (please help asap thanks!:)

Chemistry

1 answer:

Kay [80]2 years ago

3 0

Answer:

The correct answers are:
"Only about 3 percent of Earth's water is fresh water."

"About 75% percent of the fresh water on Earth is frozen in ice sheets."

"The largest source of usable fresh water is groundwater."

Explanation:

3 percent of Earth's water is most certainly fresh water. Confirmed with a few fact checks.

The largest source of usable fresh water on Earth is groundwater. It's more difficult to access but it's there and much more usable than water say frozen in ice on the sea.

The most correct option left would be 75% of Earth's freshwater being in ice sheets even though it's about 70%.

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A container has a mixture of NO2 gas and N2O4 gas in equilibrium. The chemical reaction between the two gases is described by th

kondaur [170]

Answer: The most likely partial pressures are 98.7MPa for NO₂ and 101.3MPa for N₂O₄

Explanation: To determine the partial pressures of each gas after the increase of pressure, it can be used the equilibrium constant Kp.

For the reaction 2NO₂ ⇄ N₂O₄, the equilibrium constant is:

Kp = $\frac{P(N_{2}O_{4} )}{P(NO_{2} ^{2}) }$

where:

P(N₂O₄) and P(NO₂) are the partial pressure of each gas.

Calculating constant:

Kp = $\frac{38.8}{61.2^{2} }$

Kp = 0.0104

After the weights, the total pressure increase to 200 MPa. However, at equilibrium, the constant is the same.

P(N₂O₄) + P(NO₂) = 200

P(N₂O₄) = 200 - P(NO₂)

Kp = $\frac{P(N_{2}O_{4} )}{P(NO_{2} ^{2}) }$

0.0104 = $\frac{200 - P(NO_{2}) }{[P(NO_{2} )]^{2}}$

0.0104 $[P(NO_{2} )]^{2}$ + $P(NO_{2} )$ - 200 = 0

Resolving the second degree equation:

$P(NO_{2} )$ = $\frac{-1+\sqrt{9.32} }{0.0208}$

$P(NO_{2} )$ = 98.7

Find partial pressure of N₂O₄:

P(N₂O₄) = 200 - P(NO₂)

P(N₂O₄) = 200 - 98.7

P(N₂O₄) = 101.3

The partial pressures are $P(NO_{2} )$ = 98.7 MPa and P(N₂O₄) = 101.3 MPa

3 0

3 years ago

When two clear, colourless liquids are mixed together, a yellow precipitate is formed. This is an example of a

Flura [38]

Answer:

Combining the two clear colorless liquids is a chemical change.

Explanation:

Because a different solid substance is formed. Tell students that a precipitate is an insoluble solid that forms when two solutions are combined and react chemically. Insoluble means that the solid will not dissolve.

3 0

3 years ago

Which reaction is single replacement?

Tatiana [17]

<span>Among the given choices, the third option is the only one which illustrates single replacement. (3)H2SO4 + Mg --> H2 + MgSO4 A single replacement is also termed as single-displacement reaction, a reaction by which an element in a compound, displaces another element. It can be illustrated this way: X + Y-Z → X-Z + Y</span>

5 0

3 years ago

Read 2 more answers

1.26 * 10^4 + 2.50 * 10^4 in sceintific notation

eduard

Hello! I can help you with this. First, convert them into it’s written out standard form. 10^4 is 10,000. 10,00 * 1.26 is 12,600. 10,000 * 2.5 is 25,000. 12,600 + 25,000 = 37,600 or 3.76 * 10^4 in scientific notation. The answer in scientific notation is 3.76 * 10^4.

8 0

3 years ago

Another carbon isotope has six protons and seven neutrons in its nucleus. What do you think this carbon isotope is called?

insens350 [35]

Answer:

Carbon - 13

Explanation:

For most of the elements other than that of hydrogen, the isotopes are named for the mass number.

Example : Carbon atoms with 6 neutrons have mass number of 12 ( as $6\ protons +6\ neutrons=12$ ), so they are known as carbon-12.