When 0.225 g of calcium carbonate is used, 54.0cm^3 of carbon dioxide is formed. Determine the mass of calcium carbonate needed to form 126cm^3 of carbon dioxide.

Please with explanation!

If 10.g of agno3 is available, what volume of 0.25 m agno3 can be prepared

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.

Most materials are not magnetic because their magnetism has worn off. their magnetic domains are arranged randomly. they lack magnetic fields. earth’s heat has destroyed their magnetism.