80.5%- The total mass of the compound is 18g (14.5 + 3.5) then divide the mass of magnesium by the total. easy way to remember is- (part/whole) x 100
Answer:
The correct option is (b) "pressure".
Explanation:
Gay-Lussac's law states that the pressure of an ideal gas is directly proportional to its temperature at constant mass and volume.
Mathematically, Gay-Lussac's law is as follows :

or

Hence, the correct option is (b) "pressure".
Answer: oxygen=2.547g
Explanation:
Based on the question,it was observed that the reaction is reversible
2 moles of KClO3 gives 2 moles of KCl and three moles of O2
Molar mass for KClO3 is 245 g/mol
Molar mass for O2 is 96 g/mol
We are to find the mass of O2 and we Are given the mass KCLO3 is 6.50g
245g of KClO3 gives 96g of O2
6.50g of KClO3 gives xg of O2
Cross multiply
245x=624
X=624/245
X=2.547g
Therefore the gram of oxygen is 2.547g