What is the half-life of a 3 g sample of radioisotope that decayed to 0.75 g in 30 days?

Melting 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.

Which property of a rock remains unchanged by mechanical weathering? a. total surface area b. size and shape c. mineral composition d. sharpness

Acompound has the molecular formula c3h8. which class of organic compounds does it belong to?