Answer:
organic chemistry is chemistry focused on structure and composition, extending to recations and properties of compounds.
often centered around compounds with carbon.
alcohols, amines, and aldehydes are some groups that are studied on organic chemistry
SHORT ANSWER:
a) chemistry focused on the structure qnd composition of compounds
b) alcohols, amines, aldehydes
The answer is 267.93 g
Molar mass of CaBr2 is the sum of atomic masses of Ca and Br:
Mr(CaBr2) = Ar(Ca) + 2Ar(Br)
Ar(Ca) = 40 g/mol
Ar(Br) = 79.9 g/mol
Mr(CaBr2) = 40 + 2 * 79.9 = 199.8 g/mol
The percentage of Br in CaBr2 is:
2Ar(Br) / Mr(CaBr2) * 100 = 2 * 79.9 / 199.8 * 100 = 79.98%
Now make a proportion:
x g in 79.98%
335 g in 100%
x : 79.98% = 335 g : 100%
x = 79.98% * 335 g : 100%
x = 267.93 g
Answer: 63.26%
Explanation:
If we let the abundance of the first isotope be x, then:
Which is equal to <u>63.26%</u>
Answer:
He developed the concept of concentric electron energy levels
Explanation:
Before Bohr's model, Rutherford's model was proposed. This model explains most of the properties of the atom but failed to explain the stability of the atom.
As per Rutherford's model, electrons revolve around the nucleus in the orbit.
But revolving electron in their orbit around nucleus would give up energy and so gradually move towards the nucleus and therefore, eventually collapse.
Bohr's proposed that the electrons around the nucleus move orbit of fixed energy called "stationary states". Electrons in these stationary states do not radiate energy.
Therefore, proposal of concentric electron energy levels refine the atomic models.
c. online college and career planning resource you can access once you take the PSAT.
Explanation:
MyRoad is an online platform where college and career planning resources can be accessed when the PSAT has been taken.
It provides an online mentor-ship and guidance for approaching the more robust college life.
The platform allows diverse students to access useful information about their intended colleges.
It also helps in determining career choices and a host of other resources.
