Table Giving Answer
Element Atomic mass % Amount
Mg_24 24 79 18.96
Mg_25 25 10 2.5
Mg_26 26 11 2.86
Total 24.32
Discussion
The method of calculation for this table, which was done in Excel (a spread sheet) is shown below. Assume that there is 100 grams of material of "pure" magnesium. What is it's mass?
<em><u>Sample Calculation</u></em>
The the sample atomic mass = 24
Mass = % * sample atomic mass
Mass = 79% * 24
Mass = (79/100) * 24
Mass = 18.96
<em><u>Note</u></em>
The other two elements are found exactly the same as the sample calculation.
Then all you do is add the 3 masses together.
Answer
The mass of Mg to 1 decimal place is 24.3 <<<< Answer.
Explanation:
mass H2O2 = 55 mL(1.407 g/mL) = 80.85 g
molar mass H2O2 = 2(1.01 g/mol) + 2(16.00 g/mol) = 34.02 g/mol
moles H2O2 = 80.85 g/34.02 g/mol = 2.377 moles H2O2
For each mole of H2O2 you obtain 0.5 mole of O2 (see the equation).
moles O2 = 2.377 moles H2O2 (1 mole O2)/(2 moles H2O2) = 1.188 moles O2
Now, you need the temperature. If you are at STP (273 K, and 1.00 atm) then 1 mole of an ideal gas at STP has a volume of 22.4 L. Without temperature you are not really able to continue. I will assume you are at STP.
Volume O2 = 1.188 moles O2(22.4 L/mole) = 0.0530 L of O2.
which is 53 mL.
Answer:
5.17.
Explanation:
<em>∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.
</em>
[OH⁻] = 1.5 x 10⁻⁹ M.
∴ [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(1.5 x 10⁻⁹ M) = 6.66 × 10⁻⁶ M.
∵ pH = - log[H₃O⁺]
<em>∴ pH = - log(6.66 × 10⁻⁶ M) = 5.17.
</em>
Answer:
15.69 dozen
Explanation:
Mass of penny = 5 g
Dozens of penny =..?
Next, we shall convert 5 g to gross. This can be obtained as follow:
3824 g = 1000 gross
Therefore,
5 g = 5 g × 1000 gross / 3824 g
5 g = 1.3075 gross
Thus, 5 g is equivalent to 1.3075 gross.
Finally, we convert 1.3075 gross to dozen. This can be obtained as follow:
1 gross = 12 dozen
Therefore,
1.3075 gross = 1.3075 gross × 12 dozen / 1 gross
1.3075 gross = 15.69 dozen
Thus, 5 g of penny is equivalent to 15.69 dozen
