Enantiomer of cis-1-chloro-3-methylcyclopentane

Draw the enantiomer of cis-1-chloro-3-methylcyclopentane which is R at C-1.

1)  What is the configuration of this molecule at C-3 (R and S)?

2)  When cis-1-chloro-3-methylcyclopentane and trans-1-chloro-3-methylcyclopentane are treated with sodium iodide in aqueous acetone, their rates of substitution are strikingly different.  Explain clearly why this is so.