The atomic number (Z) uniquely identifies a chemical element. In an uncharged atom, the atomic number is also equal to the number of electrons.
The atomic number, Z, should not be confused with the mass number, A, which is the number of nucleons, the total number of protons and neutrons in the nucleus of an atom.
In this video Kristine Born explains this two concepts in more detail.
Answer:
yes I do think they mean the same thing
Explanation:
150 grams and 150 grams is the same thing and adding 0 to the end of a decimal does not change its value, you could even put 150.0000000 grams and it would still be equivalent to the other numbers
Answer:
It takes 86 days take to cover half of the lake
Explanation:
In the day #1, the amount of the algae is X,
In the day #2 is 2X
In the day #3 is 2*2*X = X*2²
...
In the day #n the amount of the algae is X*2^(n-1)
Assuming X = 1m³. In the day 87, the area infected was:
1m³*2^(87-1)
7.74x10²⁵m³ is the total area of the lake
the half of this amount is 3.87x10²⁵m³
The time transcurred is:
3.87x10²⁵m³ = 1m³*2^(n-1)
Multiplying for 5 in each side:
ln (3.87x10²⁵) = ln (2^(n-1))
58.9175 = n-1 * 0.6931
85 = n-1
86 = n
<h3>It takes 86 days take to cover half of the lake</h3>
Answer:
False
Explanation:
Laboratory synthesis of aspirin is done by the acetylation of salicylic acid with the help of acetic anhydride .
As , the acid anhydride is very sensitive to moisture , as it can hydrolyze into two molecules of acids,
Hence , the reaction involving acid anhydride are conducted in anhydrous solvents .
Hence ,
if water is present in the glassware then , some of the acetic anhydride is wasted , Which in turns reduces the yield than that expected .
Answer:
Chemical bond can be define as a force holding atoms firmly together to a form molecules.
Explanation:
Chemical bond is a strong attraction between atoms, molecules or ions that enhance the formation of chemical compounds. The bonds may be due from the electrostatic force of attraction between opposite charged ions or through the sharing of electrons.
Types of chemical bond
There are four types of chemical bonds
- covalent bond
- polar bond
- ionic bond
- hydrogen bond
Ionic bond involves the transfer of an electron which involves one atom receiving and the other giving out
Covalent bond involves the sharing of electrons between two atoms
Polar bonds involves two atoms connected by covalent bonds which may exert different attractions for the electrons in the bond resulting into unevenly charges distribution
Hydrogen bond: this is found mostly in water H2O. They are polarized
