Democritus was the first to propose the idea of the atom. He said the atom was just this tiny, solid sphere. However, he used no scientific evidence to support his claim, so a guy named John Dalton did some experimenting and basically backed up Democritus' claim with evidence. Then, a guy named J.J. Thompson came along and said the atom was not solid and that is consisted of tiny negatively charged particles(electrons) and he came up with the Plum Pudding model which is just a tiny sphere with a punch of random scattered dots in it. After that, Ernest Rutherford did experiments and found that the tiny sphere is made up of mostly empty space with a tiny, dense, positively charged sphere inside of it, and the negatively charged particles just randomly float around it. Neils Bohr then said that the electrons take specific, circular, evenly spaced paths. Then, finally, we come to the Quantum Mechanical Model which is the one accepted today. This model basically vetos Bohr's idea and has a nucleus inside of an electron cloud, which is where the electrons are found.
The answer is 3. As 5 * 3 = 15.
Is there any other equations I may be able to help you with? :)
Answer: 40.5 mol
Explanation:
Since this is a double replacement reaction, the unbalanced equation is something like follows:
Balancing this equation,
From this equation, we can conclude that for every 3 moles of sodium hydroxide consumed, 1 mole of potassium phosphate is consumed.
This means the answer is 13.5(3)=<u>40.5 mol</u>
Take any compound, for example Al2O3.
For determining %composition of an element in the compound, divide total mass of the element with total mass of the compound and then multiply it by 100.
In the case of Al2O3, if we have to find the % composition of oxygen then,
R.M.M. of Al2O3 = 2×27 + 3×16
= 54 + 48
= 102
Percent composition of oxygen
= (G.M.M. of oxygen/R.M.M. of
Al2O3) × 100
= (48/102) × 100
=47.06%
