The rock in a particular iron ore deposit contains 78% Fe2O3 by mass. How many kilograms of the rock must a mining company process to obtain 1.0 x 103 kg of iron?

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

The valence of aluminum is +3, and the valence of the chlorine is -1. the formula fir the aluminum chloride is correctly written as

Does the number of ions in solution increase, decrease, or remain constant? it continuously decreases. it continuously increases. it decreases at first, then increases. it increases at first, then decreases.