Using a jar with a tight fitting lid, a student mixes 2.0 grams of calcium metal and 100 mL of water, the lid is placed on the bottle. The calcium dissolves and gas bubbles rise to the surface of the liquid. What do you predict has happened to the mass of the material inside the jar? a. The mass has decreased
b. The mass has increased
c. The mass is now 98 grams
d. The mass has not changed

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

Which proportionality applies to avogadro’s law?

According to thomson, the atom is a positively charged cloud with electrons scattered throughout. what would the alpha particles do when they hit the foil if thomson were correct