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Answer:
T₂ = 392 K
Explanation:
Given that,
Initial volume of the hot air balloon, V₁ = 55500 m³
Initial temperature, T₁ = 21°C = 294 K
Final volume, V₂ = 74000 m³
We need to find the final temperature inside the balloon. The relation between the temperature and volume is given by charles law i.e.

Where
T₂ is the final temperature
So,

So, the new temperature is 392 K.
Molar mass of MgCO3 is 84.313 g/mol
You can calculate this from data on the periodic table:
Molar mass Mg = 24.305g/mol
molar mass C = 12.011g/mol
molar mass O = 15.999g/mol mass 3 mol = 47.997g
Total = 84.313g/mol
Mass to be used in 1.2L of 1.5M solution = 84.313g * 1.2L * 1.5mol /L = 151.763g
I have not taken significant figures into account
The balanced equation you provide is not necessary in this calculation
1 mole CO2 = 44.0096 grams CO2
<span>2.1 mol CO2 x (44.0096 grams CO2/1 mole CO2) = 92.4 grams CO2</span>
Displacement, usually the method that is used to measure the volume of an irregularly shaped object.