Answer:
Water is polar because it has two unshared pairs of electrons on the central oxygen molecule. This causes the single covalent bonds between the central oxygen and both hydrogen to be pushed away. The hydrogen side of the water molecules has a positive charge and the oxygen side of the molecules has a negative charge.
The phosphate group contribute the following functional features to the structure of phospholipids:
1. Negative charge to interact with water.
2. Place to attach another small molecule.
The phosphate group is made up of four atoms of oxygen which are attached to one atom of phosphorus. This molecule has a net negative charge of -3. In the phospholipid molecule, the phosphate enhanced the polarity of the phospholipid head by mean of its negative charge which react with water. Phosphate group also provide a point where other small molecules such as alcohol, serine, etc can be attached.
The answer is 60.3% magnesium, 39.7% oxygen.
Solution:
The chemical equation for the reaction is 2 Mg + O2 → 2 MgO.
Since magnesium reacts completely with oxygen, it is the limiting reactant in the reaction. Hence, we can use the number of moles of magnesium to get the mass of MgO produced:
moles of magnesium = 14.7g / 24.305g mol-1
= 0.6048 mol
mass of MgO = 0.6048mol Mg(2 mol MgO/2mol Mg)(40.3044g MgO/1 mol MgO)
= 24.376g MgO
We can now solve for the percentage of magnesium:
% Mg = (14.7g Mg / 24.376g MgO)*100% = 60.3%
We also use the number of moles of magnesium to get the mass of oxygen consumed in the reaction:
mass of O2 = 0.6048 mol Mg (1mol O2 / 2mol Mg) (31.998g / 1mol O2)
= 9.676g
The percentage of oxygen is therefore
% O2 = (9.676g O2 / 24.376g MgO)*100%
= 39.7%
Notice that we can just subtract the magnesium's percentage from 100% to get
% O2 = 100% - 60.3% = 39.7%
Answer:
I think it both physical & chemical change :')
