Answer:
0.625 g
Explanation:
Given data:
Half life of radon-222 = 3.8 days
Total mass of sample = 10 g
Mass left after 15.2 days = ?
Solution:
Number of half lives = T elapsed / Half life
Number of half lives = 15.2 / 3.8
Number of half lives = 4
At time zero = 10 g
At first half life = 10 g/2 = 5 g
At 2nd half life = 5 g/ 2= 2.5 g
At third half life = 2.5 g/2 = 1.25 g
At 4th half life = 1.25 g/2 = 0.625 g
The atomic number increases moving left to right across a period and subsequently so does the effective nuclear charge. Therefore, moving left to right across a period the nucleus has a greater pull on the outer electrons and the atomic radii decreases.
Q. How many molecules of H2O can be produced from reactants in container below?
A. 3 molecule of molecules H2O will be produced from reactants in container.
<em><u>Explanation</u><u>:</u></em>
There are seven molecules of H2 and three molecule of O2 are there in the container Q, 6 molecules of H2 will react with 3 molecules of O2 to produce 3 molecules of H2O. One molecule of Hydrogen will not take part in reaction and will be present in container Q after then reaction, and the mass in overall reaction is conserved!
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