The elements of a heterogeneous mixture can be distinguished visually what dose it mean?

An observation that requires measurement is called quantitative observable or qualitative

Freezing and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.

How many moles are contained in 5.6 l of h2 at stp