Answer:
A Variac or Powermite; gradually; 50-60%.
Explanation:
A chemical reaction can be defined as a chemical process which typically involves the transformation or rearrangement of the atomic, ionic or molecular structure of an element through the breakdown and formation of chemical bonds to produce a new compound or substance.
Some of the laboratory apparatus (equipment) used for conducting a chemical reaction are conical flask, Bunsen burner, beaker, tongs, crucible, round bottom flask etc.
In order to heat a round bottom flask in a heating mantle, plug the heating mantle into a Variac or Powermite which is typically used for controlling the level of temperature. Turn the heat up gradually, and do not exceed 50-60% of the maximum output of the device, so as to avoid any electrical issues such as overloading, short-circuit etc.
The safety precautions that must be taken when using a round bottom flask are;
I. A proper inspection of the round bottom flask for cracks, irregularities or any imperfection.
II. Ensure you avoid heating the flask while it is closed.
III. When suspending the round bottom flask on a stand, you should ensure that you use a clamp for stability.
The answer is the Mesozoic Era
A solid dissolves in abolishing forms from the mixing of 2 liquids
Answer:
Atom is the building block of matter. The atom itself made up of subatomic particles electron, proton and neutron.
Explanation:
Long time ago, Greek philosopher thoughts that matter can be divided into smaller particles until a point is reached when the basic unit is obtained which can not be further sub divided. A Greek philosopher Democritus called these basic units "Atom".
Later on modern research showed that atom could be divided into smaller particles electron, proton and neutron. These smaller particles are called sub-atomic particles of atom.
Atoms are the fundamental unit of matter. Every thing in the universe that occupy space and have mass is called matter. we can say that every matter is composed of atoms. while the atom is composed of subatomic particles called electron proton and neutron.
Electron:
The electron is subatomic particle that revolve around outside the nucleus and has negligible mass. It has a negative charge.
Symbol = e-
Mass= 9.10938356×10-31 Kg
It was discovered by j. j. Thomson in 1897 during the study of cathode ray properties.
Proton and Neutron:
An atom consist of positively charged central core (nucleus) that is made up of Proton and neutron. Proton has positive charge while neutron is electrically neutral. Proton is discovered by Rutherford while neutron is discovered by James Chadwick in 1932.
Symbol of proton= P+
Symbol of neutron= n0
Mass of proton=1.672623×10-27 Kg
Mass of neutron=1.674929×10-27 Kg
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons.
