Answer: The correct statement is (A new substance is formed and the process can usually NOT be undone.)
Explanation:
A chemical reaction is simply defined as the reaction between two or more elements in which a new substance is formed and the process can usually not be undone. Different types of chemical reaction includes:
-- combination reaction: this occurs when two or more reactants form a product. For example: In the burning of coal, It combines with oxygen to produce carbon dioxide. Also in the burning of wood, carbon dioxide is given off and ashes are formed. Because new substance is being formed, they often can't be undone. The ashes formed can't be changed back into wood. Other types of chemical reaction are listed below.
-- Decomposition reaction
-- Single displacement reaction
-- Double displacement reaction
-- combustion reaction
-- Redox reaction
For the product of a chemical reaction to be undone (reversed), it has to undergo another chemical process different from the one that produced it.
Answer: The value of 
for chloroform is 
when 0.793 moles of solute in 0.758 kg changes the boiling point by 3.80 °C.
Explanation:
Given: Moles of solute = 0.793 mol
Mass of solvent = 0.758
As molality is the number of moles of solute present in kg of solvent. Hence, molality of given solution is calculated as follows.
Now, the values of 
is calculated as follows.
where,
i = Van't Hoff factor = 1 (for chloroform)
m = molality
= molal boiling point elevation constant
Substitute the values into above formula as follows.
Thus, we can conclude that the value of for chloroform is when 0.793 moles of solute in 0.758 kg changes the boiling point by 3.80 °C.
If you were to cut the radium in half and have only 90 g, it will take up 18 cm³.
<h3>
What is density?</h3>
The density of an object is the ratio of mass to volume of object.
Density = mass/volume
volume = mass/density
at a constant density, the volume of an object is proportional to its mass.
From the question, you have 180 g of radium that takes up 36 cm ^ 3 of space if you were to cut it in half and have only 90 g, the new mass will take the following volume.
180 g = 36 cm³
90 g = ?
= (90 x 36) / 180
= 18 cm³
Thus, if you were to cut the radium in half and have only 90 g, it will take up 18 cm³.
Learn more about radium here: brainly.com/question/23781489
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Answer:
b) The boiling point of the solution is always greater than the boiling point of the pure solvent.
Explanation:
Hello,
In this case, when we add a nonvolatile solute to a volatile solvent which has a relatively low boiling point, we can evidence the increase of the boiling point of the resulting solution as more energy must be supplied to take the molecules from liquid to gas. This fact matches with the boiling point elevation colligative property due to the solute's addition, which states that the boiling point of the solution is always greater than the boiling point of the pure solvent, therefore, answer is b).
Best regards.
Answer:
pH of 4
Explanation:
Upon comparing a solution with a pH value of 4 and that having a pH of 7, you will realize that it has a pH difference of 3 although the concentration of ions of hydrogen having a pH of 7 is 1000 times greater than being at a pH of 4.
