how does cpu read 32 bit word from memory I'm interested in how  does cpu read 32 bit word from memory .If the processor has 32 bits of address space then it can  address 4,294,967,295 locations  (or 4 gb) Does this mean that each location has 32 bits.?
Address Space and Word Size are indeed two different things. If my processor has an $n$ bit address space, then it can address $2^n$ addresses. Note that this is merely the number of addresses and is not $2^n$ GB.

The word size of a memory refers to the size of the smallest addressable unit of the memory. In other words if my processor has an $n$ bit address space and a word-size of $b$ bytes, then my processor can address $2^n$ locations each of which are $b$ bytes long.