Answer:
physical change because the gaseous water is chemically the same as the liquid
Explanation:
Matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states.
Generally, matter exists in three (3) distinct or classical phases and these are; solid, liquid and gas.
A physical change can be defined as a type of change that only affects the physical form of a chemical substance (matter) without having any effect on its chemical properties. Thus, a physical change would only affect the physical appearance and properties of a chemical substance (matter) but not its chemical properties.
This ultimately implies that, a physical change result in a change of matter from one form or phase (liquid, solid or gas) to another without a corresponding change in chemical composition.
Hence, the boiling of water is considered to be a physical change because the gaseous water is chemically the same as the liquid i.e there isn't any changes in chemical composition of water when boiling.
Answer: This was because the experiment showed that a substance could emit radiation even while it was not exposed to light.
Answer : The volume of pure diamond is 
Explanation : Given,
Density of pure carbon in diamond = 
Moles of pure diamond = 23.7 moles
Molar mass of carbon = 12 g/mol
First we have to calculate the mass of carbon or pure diamond.
Molar mass of carbon = 12 g/mol

Now we have to calculate the volume of carbon or pure diamond.
Formula used:

Now putting all the given values in this formula, we get:

Volume = 
As we know that:

So,
Volume = 
Volume = 
Therefore, the volume of pure diamond is 
Answer:
5 mg
Explanation:
If one half life is 4 hours, then 3 half lives is 12 hours.
This means that the sample will decay to 1/8 of its original amount.
So, the answer is 40(1/8) = 5 mg.
Hello!
The H₃O⁺ concentration can be found using the definition of pH and clearing the equation for [H₃O⁺]. The solution has a pH lower than 7, so the Sauvignon Blanc is
acid. The calculation for [H₃O⁺] is shown below:
![pH=-log [H_3O^{+}]](https://tex.z-dn.net/?f=pH%3D-log%20%5BH_3O%5E%7B%2B%7D%5D%20)
![[H_3O^{+}]= 10^{-pH}=10^{-3,24}=0,00058M](https://tex.z-dn.net/?f=%5BH_3O%5E%7B%2B%7D%5D%3D%2010%5E%7B-pH%7D%3D10%5E%7B-3%2C24%7D%3D0%2C00058M%20)
So, the concentration of H₃O⁺ in a Sauvignon Blanc with a pH of 3,24 is
0,00058 MHave a nice day!