A hot plate, a large beaker of water, and grains of rice are used in a class demonstration. When the water begins to boil, the rice moves in a circular pattern. The model demonstrates

Which type of bonding involves the complete transfer of a valence electron from a less electrogrative atom to a more electronegative one

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

Drug abuse will not lead to physical and psychological dependence. true or false ?