[achibaby1974]

The final one:

An alpha particle (mass = 6.6 x 10 ^ -24 g) emitted by radium travels at 3.4 x 10 ^ 7   +/- (plus or minus) 0.1 x 10 ^ 7 mi/h. What is its de Broglie wavelength in meters?

De Broglie: wavelength = (Planck’s constant) / (mass x velocity)

What’s the deal with the +/-? What does that mean? Is there a range for the answer? The only thing I can think of is to solve both ways and see which one yields a (-) answer because it says the particle is emitted meaning it loses energy, meaning exothermic. But we're talking about wavelength so I'm confused. And what about the radium? Is there any significance to it?           

Thank you for any help at all. I have a test on Monday and I can't figure these 3 out.

[macman104]

the +/- is just an error bound.  So you would, I imagine solve for both ends of the possibility, 3.3x10^7 and 3.5x10^7.  The fact that it is Radium is just filler information, it could be any element.  This is a pretty straightforward "plug and chug" problem.