Answer:
polar covalent bonds
Explanation:
Phosphorus trichloride is a chemical compound of phosphorus and chlorine, having the chemical formula PCl 3. It has a trigonal pyramidal shape, owing to the lone pairs of electrons on the phosphorus atom.
Chlorine is more elctronegative than phosphorus . Phosphorus has a lone pair of electrons and every chlorine atom has three pairs of electrons . The molecule is not symmetrical as the shared electron pairs are closer to the chlorine atoms than the phosphorus atoms , the chlorine atoms are shifted towards one side of the center of the molecule , thus a net dipole effect is created. This is the reason why the molecule is polar .
A visual representation of covalent bonding which represents the valence shell electrons in the molecule is said to be a Lewis structure. The lines represents the shared electron pairs and dots represents the electrons that are not involved in the bonding i.e lone pairs.
Number of valence electrons in each atom:
For Carbon, 
= 4
For Hydrogen, 
= 1
For Nitrogen, 
= 5
The Lewis structure of 
is shown in the attached image.
The formula of calculating formula charge = 
-(1)
where, F.C is formal charge, V.E is number of valence electrons, N.E is number of non-bonding electrons and B.E is number of bonding electrons.
Now, calculating the formal charge:
For on left side:
For :
For on right side:
The formula charge of each atom other than hydrogen is shown in the attached image.
Answer:
62.98 % of the sample of hydrate is water
Explanation:
Step 1: Data given
Mass of the sample of a hydrate of sodium carbonate (Na2CO3) = 2.026 grams
After heating, the mass of the sample is 0.750 g
Molar mass H2O = 18.02 g/mol
Step 2: Calculate mass of water
Mass water = mass of hydrate - mass of sample after heating
Mass water = 2.026 grams - 0.750 grams
Mass water = 1.276 grams
Step 3: Calculate mass % percent of water
Mass % of water = (mass of water / total mass hydrate) * 100 %
Mass % of water = (1.276 grams / 2.026 grams) *100 %
Mass % of water = 62.98 %
62.98 % of the sample of hydrate is water
