Answer:
12) In the ball and stick model, an orange ball representing the phosphorus atom and three green balls representing chlorine atoms are connected by means of sticks that are coloured halfway green and orange respectively to represent the shared electrons between phosphorus and chlorine with the chlorine atoms forming the base of a triangular pyramid while the phosphorus atom forms the top of the pyramid.
13) The scientist will have 6 grams of product as before but will have two grams of unreacted copper atoms because the mass ratio of copper to sulfur in this reaction is 2:1
Explanation:
12) Phosphorus trichloride has a trigonal pyramidal structure and is composed of three atoms of chlorine and one atom of phosphorus.
In the ball and stick model, an orange ball representing the phosphorus atom and three green balls representing chlorine atoms are connected by means of sticks that are coloured halfway green and orange respectively to represent the shared electrons between phosphorus and chlorine with the chlorine atoms forming the base of a triangular pyramid while the phosphorus atom forms the top of the pyramid.
13) The reaction between copper and sulfur to form copper sulfide is shown in the equation below:
Cu + S ---> CuS
1 mole of copper reacts with 1 mole of sulfur to produce 1 mole of copper sulfide
molar mass of copper = 64 g/mol; molar mass of sulfur = 32 g/mol, molar mass of copper sulfide = 96 g/mol
mass ratio of copper to sulfur = 63 g/ 34 g = 2
This means that 2 grams of copper will react with 1 g of sulfur to produce 3 grams of product. similarly, 4 g of copper will react with 2 g of sulfur to produce 6 grams of product.
Therefore 6 g of of copper will react with 3 g of sulfur. However, since the amount of sulfur available for reaction is 2 g only, 2 g of copper will be left unreacted after 4 g has reacted completely with 2 g of sulfur to produce 6 g of copper sulfide.