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.
Nonmetallic binds are commonly
Explanation:
Mole ratio of NaOH to H2O = 2 : 1
Moles of H2O = 1.85mol * (1/2) = 0.925mol.
Mass of H2O = 0.925mol * (18g/mol) = 16.65g.
Half life is defined as the time when the final concentration reduced to half of the initial value.
Thus, for first half life, the remaining percentage of the reactant is 50 percent that is 
Now, for second half life, the remaining percentage will be 50 percent of the remaining 50 percentage that is 
or 
Thus, general formula for n half lives =
Now, 98.4 years is equal to eighth times 12.3 years that is 
=
remaining material.
Therefore, mass of the nuclide will remain after 98.4 years= 
= 
Mass of remaining nuclide after 98.4 years =
ANSWER - 48.83%
Mg - 24.31
S - 32.07
O - 16x4 - 64
ADD ALL TOGETHER = 120.38
H - 1.01x2 - 2.02
O - 16
TOTAL = 18.02x7 = 126.14
ADD 120.38 to 126.14 = 246.52
last part divide MgSO4 by total compound mass
120.38/246.52 then multiply by 100 = 48.831
