The atomic number is the number of Protons on the nucleus of the atom, whereas the mass number of some isotope is the mass of the protons plus the mass of the neutrons. That's the difference between isotopes: number of neutrons.
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Answer:
Na₂CO₃ · 10H₂O
Explanation:
The formula for sodium carbonate hydrate is:
Na₂CO₃ · xH₂O
The unknown "x" is the number of water molecules contained in the hydrate.
To find "x" we have to use the hydrogen percentage in the sample, 7.05 % H.
First we calculate the molecular weight of Na₂CO₃ · xH₂O:
molecular weight of Na₂CO₃ · xH₂O = 23 × 2 + 12 + 16 × 3 + 18x
molecular weight of Na₂CO₃ · xH₂O = 106 + 18x g/mole
Now we devise the fallowing reasoning tanking in account 1 mole of Na₂CO₃ · xH₂O:
if in 106 + 18x grams of Na₂CO₃ · xH₂O we have 2x grams of hydrogen
then in 100 grams of Na₂CO₃ · xH₂O we have 7.05 grams of hydrogen
106 + 18x = (100 × 2x) / 7.05
106 + 18x = 28.4x
106 = 28.4x - 18x
106 = 10.4x
x = 106 / 10.4
x = 10.2 ≈ 10
The formula for the washing soda is Na₂CO₃ · 10H₂O.
Given , Speed of light = 3 × 10⁸ m/s
Distance = 40 × 1.61× 1000 m
= 264400 m
We know that, speed = distance/time
so, time = distance/speed
t = 264400 / 3 × 10⁸
t = 0.00881333 sec Approx
The answer is 0.00881333 sec Approx
Answer:
In physics, action is an attribute of the dynamics of a physical system from which the equations of motion of the system can be derived through the principle of stationary action. ... Action has dimensions of energy⋅time or momentum⋅length, and its SI unit is joule-second.
Explanation:
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