I'm confused on how to do these. Please show and explain how to do these. Test/quiz may be tomorrow. Pop Quiz!!!
How do you calculate the percent composition of each of the following compounds?
a.) Magnesium hydroxide
b.) Calcium Cyanide
c.) Nickel (ii) Iodide
d.0 Copper (i) Sulfide
HELP! Thanks
The percent composition in these problems means to calculate the percent of each element versus the entire compound.
It works this way. Suppose you have 10 lbs apples and 5 pounds oranges. What is %apples and %os.
%apples = (weight apples/total weight)*100 = (10/15)*100 = 66.67
So for Mg(OH)2, the molar mass is 58.3 (that's 24.3+16+16+1+1).
So %Mg = (24.3/58.3)&100 = ?
%O = (32/58.3)*100 = ?
etc/
To calculate the percent composition of a compound, you need to determine the relative masses of its constituent elements. Here's how you can calculate the percent composition for each of the given compounds:
a.) Magnesium hydroxide (Mg(OH)2)
To calculate the percent composition of magnesium hydroxide, you need to determine the mass of each element (magnesium, oxygen, and hydrogen) in the compound.
1. Find the molar masses:
- Magnesium (Mg) has a molar mass of 24.31 g/mol.
- Oxygen (O) has a molar mass of 16.00 g/mol.
- Hydrogen (H) has a molar mass of 1.01 g/mol.
2. Calculate the mass of each element by multiplying the molar mass by the number of atoms in the compound:
- Magnesium: 1 atom x 24.31 g/mol = 24.31 g/mol
- Oxygen: 2 atoms x 16.00 g/mol = 32.00 g/mol
- Hydrogen: 2 atoms x 1.01 g/mol = 2.02 g/mol
3. Add up the masses to determine the total molar mass of the compound:
Total molar mass = 24.31 g/mol + 32.00 g/mol + 2.02 g/mol = 58.33 g/mol
4. Calculate the percent composition of each element by dividing the mass of each element by the total molar mass and multiplying by 100:
- Magnesium: (24.31 g/mol / 58.33 g/mol) x 100% ≈ 41.7%
- Oxygen: (32.00 g/mol / 58.33 g/mol) x 100% ≈ 54.9%
- Hydrogen: (2.02 g/mol / 58.33 g/mol) x 100% ≈ 3.5%
Therefore, the percent composition of magnesium hydroxide is approximately: 41.7% magnesium, 54.9% oxygen, and 3.5% hydrogen.
b.) Calcium Cyanide (Ca(CN)2)
Follow the same steps as above to calculate the percent composition for calcium cyanide using the appropriate molar masses for calcium (Ca), carbon (C), and nitrogen (N).
c.) Nickel (II) Iodide (NiI2)
Follow the same steps as above to calculate the percent composition for nickel (II) iodide using the appropriate molar masses for nickel (Ni) and iodine (I).
d.) Copper (I) Sulfide (Cu2S)
Follow the same steps as above to calculate the percent composition for copper (I) sulfide using the appropriate molar masses for copper (Cu) and sulfur (S).
By following these steps, you can calculate the percent composition of each compound and determine the relative masses of their constituent elements.