can any stereo receiver be turned to mono?

Simple answer is NO. That receivers amplifiers cannot be bridged for mono use. Do not follow MC's advice. What others are saying will yield 2 mono channels from either 2 different speakers or 1 speaker if that's all you connect. 

i'm an older guy who remembers that all recievers from the 70's had a mono/ stereo switch!!

Relax, it's a receiver. A $30-60 receiver, at that. Well worth trying for entertainment value alone. Or think of it as a mercy killing, like the way they do the injured horse. Only in this case afterwards while you air out the room you go on CraigsList and find half a dozen better ones listed under Free Stuff. After a quick search you go pick up the closest one, it will be sitting there on the curb, and maybe stop by get another one while you're out driving around. Then back home compare and use the least bad sounding. Just be careful not to pick up an AVR by mistake. 

Older vintage receivers had stereo/mono switches, this one does not. A stereo/mono switch does exactly the same thing as the Y-connectors others suggested. Still the amps cannot be bridged in that receiver. 

@fiesta75 

I have a Sansui 4000 (my living room stereo) that does have a mono switch. I really wish this one had a switch. 

THanks for the help everyone!