A quart is a unit for measuring volume, and a pound is a unit for measuring weight. You can’t compare the two things without knowing how dense each one is.
A quart is equal to 32 fluid ounces, while a pound is equal to 16 ounces. One pound seems like it would be the same as half a quart, but it is not. A quart is a way to measure how much space something takes up, while a pound is a way to measure how heavy something is. Water is one of the few things where the amount of liquid is the same as the weight. One quart of water weighs 32 ounces.