2.4 x 10²² atoms
<h3>Further explanation</h3>
Atomic mass is the average atomic mass of all its isotopes
In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu
So the atomic mass obtained is the mass of the atom relative to the 12th carbon atom
mass single Uranium atom=4.7 x 10⁻²² g
then for 111 mg=0.111 g
Answer:
3 years
Explanation:
Given data:
Initial amount of sample = 160 Kg
Amount left after 12 years = 10 Kg
Half life = ?
Solution:
at time zero = 160 Kg
1st half life = 160/2 = 80 kg
2nd half life = 80/2 = 40 kg
3rd half life = 40 / 2 = 20 kg
4th half life = 20 / 2 = 10 kg
Half life:
HL = elapsed time / half life
12 years / 4 = 3 years
Answer:
Oxygen
Explanation:
If two balloons are filled with hydrogen gas and helium gas respectively, then we want to identify what gas is in each balloon, we have to do so by exposing the both balloons to flame in an oxygen atmosphere.
Hydrogen combines with oxygen in the presence of a flame with quite a loud sound and the flame is sustained but when a flame is brought near helium gas in a balloon, the gas will only make a little sound when exposed to the flame and extinguish the flame.
The reason for the explosion of the gas in the hydrogen balloon is that combustion of hydrogen gas is exothermic. The heating up of surrounding air molecules leads to a sudden explosion.
However, the helium balloon makes a little sound when the balloon is ruptured releasing helium gas which extinguishes the flame.
Be= Beryllium= weight 9.01
Cl= Chlorine= weight 35.45
Since there are 2 Chlorine, you have to add Chlorine twice.
9.01 + 35.45 + 35.45= 79.91
Answer: 79.91
(This answer does not include sig.figs)
