Answer:
the correct option is option c, I and IV
Explanation:
Atomic emission spectroscopy is used to determine quantity of element in a sample.
Atomic emission spectroscopy based on occurring of atomic emission when a valence electron from higher energy orbital comes back to lower energy orbital.
Light intensity emitted by a flame, plasma, arc of particular wavelength are used to excite the valence electron.
The intensity of atomic emission lines are proportional to number of atoms present in the excited state.
Emission intensity is affected by temperature of the excitation source and the efficiency of atomization.
Increase in temperature does not affect the ground state population.
Therefore, statements I and IV are correct.
So, the correct option is c.
Answer:
2.4 moles of oxygen are needed to react with 87 g of aluminium.
Explanation:
Chemical equation:
4Al(s) + 3O₂(l) → 2AlO₃(s)
Given data:
Mass of aluminium = 87 g
Moles of oxygen needed = ?
Solution:
Moles of aluminium:
Number of moles of aluminium= Mass/ molar mass
Number of moles of aluminium= 87 g/ 27 g/mol
Number of moles of aluminium= 3.2 mol
Now we will compare the moles of aluminium with oxygen.
Al : O₂
4 : 3
3.2 : 3/4×3.2 = 2.4 mol
2.4 moles of oxygen are needed to react with 87 g of aluminium.
First blank -Same
Second blank-Neutral
