Answer:
a. Tellurium
b. Rubidium
c. Argon
d. Astatine
Explanation:
a. An element of the same family as oxygen corresponds to group 16 or 6A, its most stable ion is -2, therefore if the ion has 54 electrons the neutral element should have 52 electrons and also 52 protons. Tellurium
b. The ions from alkali metals are +1, therefore the neutral elements have 1 more electron and proton, since the ion has 36 electrons the neutral element has 37. Rubidium
c. This is direct, look for the element with Z = 18. Argon
d. This is also direct, look for the element with Z = 85. Astatine
Explanation:
In gases the molecules are held together by weak Vander waal forces. Due to this they have more kinetic energy and they tend to diffuse at a faster rate because of more number of collisions between the molecules.
That is why, its molecules readily spread into the atmosphere as compared to the molecules of solids and liquids. Also, when molecules of a gas collide with the walls of a container then they tend to come back at their initial position for a fraction of second or more.
Hence, gas collisions are elastic in nature.
According to Graham's law, rate of diffusion of a gas is inversely proportional to the square root of molar mass of the gas. Hence, more is the molecular weight of gas less likely it is able to diffuse into the surroundings.
Thus, we can conclude that following apply to gases.
- Gas collisions are elastic.
- Gases mix faster than solids or liquids.
- Gases with larger molecular weights diffuse slower than gases with lower molecular weights.
The english translation of the question is:
Paraffin combustion is a chemical change?
Answer:
Yes
Explanation:
The chemical change is defined as the change in chemical composition of substance while physical change is defined as the change in physical appearance which can return to original shape again.
The combustion of paraffin is a chemical change because during combustion the chemical structure of the paraffin has been changed.
Hence, the given statement is true.
I'm pretty sure A, B, AB, or O.