Melting tin and then cooling it into a mold is an example of reversible physical changes.
<u>Explanation:</u>
When an object undergoes a change in size, state, or shape and not in their chemical compositions referred to as physical change. But chemical change occurs as a result of the change in substances composition. It also forms a new one by the combination/ breakage of one or more objects.
In the case of making gold cube into two pieces, there is no possibility of getting the original state again even the physical change happens. Match burning and relighting and sodium plus chlorine forming table salt show chemical change. But in tin melting and cooling it to form mold is the physical change i.e changes in state(liquid to solid) and are reversible too.
Answer:
The results is Li₂O
Explanation:
n a chemical reaction, the electron miner in the formula must be balanced, that is, the number of positive and negative charges is the same
In this case, oxygen has a valence of -2 that is, it can give two electrons and lithium has a valence of +1, therefore two lithium atoms are needed for the charges to be neutral, therefore the chemical formula is
The results is Li₂O
Answer:
It is the way you see someone or something
Answer:
Explanation:
The electrostatic attraction between the nucleus and the electron is given by:
(1)
where
k is the Coulomb's constant
Ze is the charge of the nucleus
e is the charge of the electron
r is the distance between the electron and the nucleus
This electrostatic attraction provides the centripetal force that keeps the electron in circular motion, which is given by:
(2)
where
m is the mass of the electron
v is the speed of the electron
Combining the two equations (1) and (2), we find
And solving for v, we find an expression for the speed of the electron:
