molecule. 1  Chemistry, Physics. the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound. 2  Chemistry. a quantity of a substance, the weight of which, measured in any chosen unit, is numerically equal to the molecular weight; gram molecule.
When I do crunches my neck starts to tighten up and it makes me have to rest before doing another set of crunches.
1 Spike bags upright and keep the tubing upright. 2  If the bag must be placed in a horizontal position, clamp off the tubing below the drip chamber with your fingers to prevent air from getting in the neck of the drip chamber. 3  If air gets into the neck of the drip chamber it is very hard to dispel.