Consider the reaction
s2cl2(l) + ccl4(> cs2(g) + 3cl2(g); dh° = 84.3 kj
if the above reactants and products are contained in a closed vessel and the reaction system is at
equilibrium, the number of moles of cs2 can be increased by
a) increasing the size of the reaction vessel.
b) adding some cl2 to the system.
c) adding some s2cl2 to the system.
d) decreasing the temperature of the reaction system.
e) adding some ccl4 to the system.

A), C), and E)

Explanation:

We need to use the Le Chatelier´s principle to answer this question as follows:

A)  Increasing the size of the reaction vessel has the effect of decreasing pressure, so the equilibrium will shif to the side that has greater pressure which in this case is the products, so we the number of moles of CS2 will increase.

B) If we add more product Cl2 to the system it will shift to the reactants  to counteract the change in the equilibrium; therefore, some CS2 will be consumed.

C) If we add reactant S2Cl2 to the system it will shift to the product side therby increasing the number of moles of CS2

D) The reaction is endothermic so it will shift to the reactant side.

E) Adding more reactant CCl4  will shift the equilibrium to the right side favoring more CS2

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.  

explanation: it gains negative electrons, therefore becoming negatively charged. as charge cannot be created, nor destroyed, only transferred, this leaves the wool positive. now that they have opposite charges, the two items attract.