Answer: The coefficient for
is 12.
Explanation:
According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

Thus in the reactants, there are 12 molecules of oxygen in balanced chemical equation. Thus the coefficient for
is 12.
If you’re referring to he red stuff- the liquids can be ethanol, toluene, kerosene, or isoamyl acetate. They’re transparent so they’re made more visible with red dye. (So I’d guess the answer is ethanol)
I found this in the Wikipedia article ‘Alcohol thermometer’
Answer:
Mass = 824.57 g
Explanation:
Given data:
Mass of bromine = ?
Number of moles of bromine = 5.16 mol
Solution:
Formula:
Mass = number of moles × molar mass
Molar mass of bromine = 159.8 g/mol
by putting values,
Mass = 5.16 mol × 159.8 g/mol
Mass = 824.57 g
The answer is b convection