On a cool morning, uyen’s breath can form a cloud when she breathes out. which changes of state are most responsible for uyen seeing her breath in this way?

When you exhale (breathe out), your breath also containsmoisture. Because your mouth and lungs are moist, each breath you exhale contains a little bit of water in the form of water vapor(the gas form of water).

For water to stay a gas in the form of water vapor, it needs enough energy to keep its molecules moving. Inside your lungs where it's nice and warm, this isn't a problem.

a gas, having a molecular weight of 13 kg/kmol and a kinematic viscosity of 0.25 cm2/s, flows through a pipe 0.25 m internal diameter and 5 km long at the rate of 0.4 m3/s and is delivered at atmospheric pressure.