Answer:
39.7 %
Explanation:
magnesium + oxygen ⟶ magnesium oxide
10.57 g 6.96 g 17.53 g
According to the <em>Law of Conservation of Mass</em>, the mass of the product must equal the total mass of the reactants.
Mass of MgO = 10.57 + 6.96
Mass of MgO = 17.53 g
The formula for mass percent is
% by mass = Mass of component/Total mass × 100 %
In this case,
% O = mass of O/mass of MgO × 100 %
Mass of O = 6.96 g
Mass of MgO = 17.53 g
% O = 6.96/17.53 × 100
% O = 0.3970 × 100
% O = 39.7 %
Answer:
78.85
Explanation:
To <u>calculate the average atomic mass of the isotopes </u>we use the <em>given masses and abundances</em>, as follows:
- Mass of Isotope 1 * Abundance of Isotope 1 + Mass of Isotope 2 * Abundance of Isotope 2 + ....
In other words:
- 78 amu * 75/100 + 81 amu * 15/100 + 82 amu * 10/100 = 78.85
So the answer is 78.85.
32.) 55.6 mL HCl
33.) 0. 128 M