Determining the identity of substances is a critical part of chemistry because once the substance's identity is known, we can predict its behavior and understand the scenarios that it is involved in better.
For example, consider an industrial pipe where fouling (scaling) is occurring. If the compounds present in the scales are identified, steps may be taken to prevent and remove the scaling. This is one of many examples where identifying chemical substances is of high importance.
Answer:
D. A compound can be separated into two or more elements through a chemical reaction.
Explanation:
By method of elimination, we are going t obtain the correct option.
A. A compound is made up of a single atom.
This is wrong because, a compound can contain more than one atom. An example is H2O
B. A compound is made up of many atoms that are all the same type.
This is wrong because a compound can contain atoms of different elements. An example is H2O. It contains atoms of hydrogen and oxygen.
C. A compound can be separated into two or more elements through physical processes.
This is wrong. H2O being a compound cannot be separated by ordinary physical means.
D. A compound can be separated into two or more elements through a chemical reaction.
This is the correct option.
Answer: b) positron
Explanation:
The antiparticle or the antimatter counterpart of the electron is called positron.
The positron has an electric charge of +1 e and same mass as an electron. When a positron collides with an electron, annihilation takes place.
Below is an attachnent that further explains this
For this question, suppose the pressure is remained constant, we can use the Charles law to find the answer.
Charles law:
V1/T1 = V2/T2
V1 and T1 are the initial volume and temperature (in K), and V2 and T2 are the final volume and temperature.
We just need to substitute in the numbers in order to find the new volume, V2.
1/5 = V2/10
5V2 = 10
V2 = 2
Therefore, the answer would be 2m3.
