1）The mass spectrum of an average sample of a pure element is shown in the figure above. Which of the following is the identity of the element?
2)The ideal gas law best describes the properties of which of the following gases at 0°C and 1 atm?
3)At 298 K and 1 atm, Br2 is a liquid with a high vapor pressure, and Cl2 is a gas. Those observations provide evidence that under the given conditions, the
A.forces among Br2 molecules are stronger than those among Cl2 molecules
B.forces among Cl2 molecules are stronger than the Cl−Cl bond
C.Br−Br bond is stronger than the Cl−Cl bond
D.Cl−Cl bond is stronger than the Br−Br bond
4) Which of the following has the bonds arranged in order of decreasing polarity?
A.H−F > N−F > F−F
B.H−I > H−Br > H−F
C.O−N > O−S > O−Te
D.Sb−I > Sb−Te > Sb−Cl
CS2(g) + 3Cl2(g) → CCl4(g) + S2Cl2(g)
1. Carbon tetrachloride, CCl4(g) , can be synthesized according to the reaction represented above. A chemist runs the reaction at a constant temperature of 120C in a rigid 25.0 L container.
(a) Chlorine gas, Cl2(g) , is initially present in the container at a pressure of 0.40 atm.
(b) At 30℃ the reaction is thermodynamically favorable, but no reaction is observed to occur. However, at 120℃, the reaction occurs at an observable rate.
(c) S2Cl2 is a product of the reaction.
(d) CCl4(g) can also be produced by reacting CHCl3(g) with Cl2(g) at 400°C, as represented by the equation below.
CHCl3(g) + Cl2(g) → CCl4(g) + HCl(g)
At the completion of the reaction a chemist successfully separates the CCl4(g) from the HCl(g) by cooling the mixture to 70℃, at which temperature the CCl4(g) condenses while the HCl(g) remains in the gaseous state.