When you hear the word decahydrate, what number should be written in front of the formula for water?
1 answer:
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Answer:
50.8 g
Explanation:
Equation of reaction.
From the given information, the number of moles of methane = mass/ molar mass
= 15.4 g / 16.04 g/mol
= 0.960 mol
number of moles of oxygen gas = 90.3 g / 32 g/ mol
= 2.82 mol
Since 1 mol of methane requires 2 moles of oxygen
Then 0.960 mol of methane will require = 0.960 mol × 2 = 1.92 mol of oxygen gas
Thus, methane serves as a limiting reagent.
2.82 mol oxygen gas will result in 2.82 moles of water
So, the theoretical yield of water = moles × molar mass
= 2.82 mol × 18.01528 g/mol
= 50.8 g
Answer : The molecular weight of a substance is 157.3 g/mol
Explanation :
As we are given that 7 % by weight that means 7 grams of solute present in 100 grams of solution.
Mass of solute = 7 g
Mass of solution = 100 g
Mass of solvent = 100 - 7 = 93 g
Formula used :
where,
= change in freezing point
= temperature of pure water =
= temperature of solution =
= freezing point constant of water =
m = molality
Now put all the given values in this formula, we get
Therefore, the molecular weight of a substance is 157.3 g/mol