The number 4 in the 4/2He indicates the atomic mass number of helium.
Answer: Option 3
<u>Explanation: </u>
The elements present in periodic table generally represented as . Here X will be the element in the periodic table, A is the atomic mass number of the element X and Z is the atomic number of the element X.
So, the number 4 is the atomic mass number of He and He-4 is the stable isotope of helium which can also be termed as alpha particle.
Mass number = number of protons + neutrons count.
Thus the number 4 denotes the Helium's atomic mass number.
Answer:
36.92 mg of oxygen required for bio-degradation.
Explanation:
Mass of benzene = 30 mg = 0.03 g (1000 mg = 1 g )
Moles benzene =
According to reaction 5 moles of benzene reacts with 15 moles of oxygen gas.
Then 0.0003846 mol of benzene will react with:
of oxygen gas
Mass of 0.0011538 moles of oxygen gas:
0.0011538 mol × 32 g/mol = 0.03692 g = 36.92 mg
36.92 mg of oxygen required for bio-degradation.