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Nastasia [14]
3 years ago
13

The last time the atmospheric carbon dioxide level was as high as it is today was _________ years ago.

Chemistry
1 answer:
Nastasia [14]3 years ago
8 0

Answer:The last time levels of atmospheric carbon dioxide were this high came during the Pliocene Epoch, which extended from about 5.3 million to 2.6 million years ago

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A gravel can be broken down into different kinds of substances by physical processes. No chemical reactions are needed to separa
Vlada [557]

Answer:

MIXTURE

Explanation:

A mixture is a substance composed of a combination of other different substances. These component(s) of a mixture are physically combined, meaning that there is no chemical linkage between the individual components/constituents of a mixture.

This is the case of the gravel described in this question. The components of gravel can be separated using physical means because they are not chemically bonded to one another, hence, no chemical reactions are needed to separate different parts of gravel into pure substances. This makes gravel a MIXTURE.

6 0
3 years ago
Read 2 more answers
According to the phase diagram for H₂O, what happens to the phases of
sergejj [24]

Answer:

"A", "water changes from a gas to a solid to a liquid", according to this phase diagram, at at 0°C, as pressure is increased from 0atm to 10atm.

Explanation:

The question asks what happens at 0°C, as pressure is increased from 0atm to 10atm.

According to the question, the temperature is held constant.  The pressure changes.  In the phase diagram, we find the temperature 0°C on the horizontal axis, and all points where the temperature are 0°C are along that vertical line.

Since the pressure starts at 0atm and increases to 10atm, we start at the bottom, and move upward along that line, to see what phases of matter the substance changes to.

At the bottom, it is initially in a "gas" phase.  As it moves up, it transitions to a "solid" phase.  Later, as it continues moving up, it changes again into a "liquid" phase.

Thus, the answer would be "A", "water changes from a gas to a solid to a liquid", according to this phase diagram, at at 0°C, as pressure is increased from 0atm to 10atm.

8 0
2 years ago
The element with the most stable nucleus and smallest mass per particle is
Margaret [11]
"18) the element with the most stable nucleus and smallest mass per particle is:A) uranium.B)argon C) helium."
4 0
4 years ago
Why does the titration of a weak acid with a strong base always have a basic equivalence point? Why does the titration of a weak
CaHeK987 [17]

Answer: Option (c) is the correct answer.

Explanation:

When a weak acid reacts with a strong base then it results into the formation of a basic solution. Hence, the resulting solution will always have a pH greater than 7.

Since, at the equivalence point number of hydrogen ions become equal to the hydroxide ions. Therefore, pH of solution will be about 7.

So at the equivalence point, the weak acid will get neutralized due to the addition of strong base. Therefore, it will lead to the formation of conjugate base.

As a result, the solution will become slightly basic in nature.

Thus, we can conclude that at the equivalence point, the acid has all been converted into its conjugate base, resulting in a weakly acidic solution because at the equivalence point, the acid has all been converted into its conjugate base, resulting in a weakly basic solution.

5 0
3 years ago
Assuming complete dissociation, what is the ph of a 3.24 mg/l ba(oh)2 solution?
weqwewe [10]
We need to first find the molarity of Ba(OH₂) solution.
A mass of 3.24 mg is dissolved in 1 L solution.
Ba(OH)₂ moles dissolved - 3.24 x 10⁻³ g/171.3 g/mol = 1.90 x 10⁻⁵ mol
dissociaton of Ba(OH)₂ is as follows;
Ba(OH)₂ --> Ba²⁺ + 2OH⁻
1 mol of Ba(OH)₂ dissociates to form 2OH⁻ ions.
Therefore [OH⁻] = (1.90 x 10⁻⁵)x2  = 3.8 x 10⁻⁵ M
pOH = -log[OH⁻]
pOH = -log (3.8 x 10⁻⁵)
pOH = 4.42
pH + pOH = 14
therefore pH = 14 - 4.42 
pH = 9.58
6 0
3 years ago
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