Which is an example of a chemical change?
a. water evaporating from a puddle
b. cloth tearing when pulled
c. wood forming sawdust when cut
d. bread baking in an oven

Agroup of students is studying convection currents. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other in an area with warm air. after 10 minutes, the balloons are released from a height of 1 meter. which of the following do the students most likely observe? a. the balloons both rise. the cold balloon is larger than the warm balloon. b. the balloons rise at the same rate. both balloons are the same size. c. the warm balloon expands and rises. the cold balloon shrinks and sinks. d. the cold balloon expands and rises. the warm balloon shrinks and sinks.

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.

What is the temperature of 0.750 mol of a gas stored in a 6,850 ml cylinder at 2.21 atm? . 2.95 k 5.24 k 138 k 246 k