What causes a pendulum to move in an extended amount of time?

Longer pendulums swing with a lower fequency than shorter pendulums. The force of gravity accelerates the pendulum down. The momentum built up by the acceleration of gravity causes the mass to swing in the opposite direction to a height equal to the original position. So therefore I think the answer your looking for is gravity.

Only one reactant yields 2 or more products. meaning you will only have 1 product and it will break down into 2 or more products. eg. h2o -> h2 + o2