CHEMISTRY HIGH SCHOOL

A solution has a uniform composition and is able to be separated by physical means

has a heterogeneous composition and is able to be separated by physical means

has a heterogeneous composition and is able to be separated by chemical means

has a uniform composition and is only able to be separated by chemical means

Answers

Answer 1
Answer: A solution has a uniform composition and is only able to be separated by chemical means.

Related Questions

During the 1960s and 1970s, Cesar Chavezworked to unionize migrant farm workers by (1) seizing the land of the lettuce and grape growers (2) securing passage of federal legislation to limit immigration (3) using nonviolent tactics such as boycotts and hunger strikes (4) urging growers to reduce the workforce through mechanization
A sample composed only of atoms having the same atomic number is classified as(1) a compound (3) an element(2) a solution (4) an isomer
What mass of ammonium sulfate ((NH4)2SO4 132.15 g/mol) is required to produce 282 mL of a 2.50M solution of ammonium sulfate?
Describe the results of Ernest Rutherford's gold-foil experiment and explain how his results changed ideas about the distribution of positive charge within the atom.
According to the periodic table, which statement correctly describes the change from a neutral atom of an element to its ion?

A radioactive isotope has a half-life of 2.5 years. Which fraction of the original mass remains unchanged after 10 years?

Answers

In ten years, four half-lives have occurred (10/2.5=4). After one half-life, 50% of the original 100% remains. After two half-lives, 50% of the remaining 50% remains (so 25% remains).
After three half-lives, 50% of the 25% remains, so 12.5% remains.
After four half-lives, 50% of the 12.5% remains, so 6.25% remains.
After four half-lives, 6.25% of the original mass remains unchanged. In fraction form that is 6.25/100

Which compound has hydrogen bonding between its molecules?(1) CH4 (3) KH
(2) CaH2 (4) NH3

Answers

NH3 has Hydrogen bonding between its molecules. 
Yup, NH3 it is. Hydrogen bonding usually occur between hydrogen and another electronegative atom such as oxygen, nitrogen or fluorine.

A material found in air, water, or soil that is harmful to humans or other organisms1. Experiment
2. Hypothesis
3. Pollutant
4. Matter

Answers

the answer is pollutant

Which of the following elements has the ability to undergo sublimation?a. oxygen
b. carbon
c. sodium
d. iodine

Answers

The best answer to this question would be (d.) iodine. Iodine is the elements who has the ability to undergo sublimation. Iodine is an important compound in terms of nutrition, production of acetic acid and polymers. Iodine is capable of transitioning from solid to gas without any specialized process. 

The answer to your question is

d. idoine

In the ground state, each atom of an element has two valence electrons. This element has a lower first ionization energy than calcium.Where is this element located on the Periodic Table?
(1) Group 1, Period 4 (3) Group 2, Period 3
(2) Group 2, Period 5 (4) Group 3, Period 4

Answers

Answer: Option (2) is the correct answer.

Explanation:

Ionization energy is defined as the energy required to remove the most loosely bound electron from a neutral gaseous atom.

And, when we move across a period then there is a decrease in the ionization energy due to decrease in the size of atoms.

Whereas when we move down a group then there is an increase in ionization energy because of increase in size of the atoms.

Since, it is given that each atom has 2 valence electrons therefore, all the atoms belong to group 2.

And, as it has lower first ionization energy than calcium it means the atom is larger in size than calcium atom.

Hence, we can conclude that this element located in Group 2, Period 5 on the periodic table.

Final answer:

The element with two valence electrons and a first ionization energy lower than calcium would be found in Group 2, Period 5 on the Periodic Table.

Explanation:

The element you're referring to, with two valence electrons and a lower first ionization energy than calcium, would be located in Group 2, Period 5 on the Periodic Table.

Here's why: Group 2 elements, or alkaline earth metals, all have two valence electrons. Periods on the other hand, describe the energy level of an atom's outermost electrons, with higher periods corresponding to higher energy levels. Thus, an atom in a higher period would have a lower ionization energy (the energy required to remove an electron) than one in a lower period.

Therefore, because the first ionization energy is lower than calcium (which is in Group 2, Period 4) but still has two valence electrons, this element would be located one period below, in Group 2, Period 5.

Learn more about Periodic Table here:

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A mixture of oxygen, hydrogen, and nitrogen exerts a total pressure of 378 kPa. If the partial pressures of oxygen and hydrogen are 212 kPa and 101 kPa respectively, what is the partial pressure exerted by nitrogen?

Answers

What's the relationship between total and partial pressure? The total pressure is the sum of the parcial pressures!


So for us, it would be:

378= 212+101+x

where x is the parcial pressure of nitrogen.

Now we count:
378= 212+101+x
378=313+x
378-313=x
65=x

So the parcial pressure exerted by nitrogen is 65!
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