Solve these problems like weighted averages:
The first one:
Multiply the masses (isotope numbers) by the decimal form of the percentage. Add them
0.076 (6) + 0.924 (7) = 6.924
The second one:
0.2 (10) + 0.8 (11) = 10.8
If you think about it, these answers make sense. 6.924 is much closer to 7 than to 6 (since there's a lot more lithium-7 than there is lithium-6). 10.8 is closer to 11 than to 10.
Format Method - Writing the symbol of the cation and then the anion. Add whatever subscripts in order to balance the charges.
Crisscross Method - The numerical value of the charge of each ion is crossed over and becomes the subscripts for the other ion.
The answer is A. Aluminum Chloride it does not have the prefix "tri-" since it is ionic.
Answer:
16.0 g; 3.1 mol
Explanation:
(a) Mass of O atoms
Mass = 6.022 × 10^23 atoms × (2.66 × 10^-23 g/1 atom) = 16.0 g
(b) Moles of O atoms
0.050 kg = 50 g
Moles = 50 g × (1 mol/16.0 g) = 3.1 mol
