The cell has a potential of 0.2106 v when the solution in the right-hand compartment is a buffer of ph 4.006. calculate the ph and the hydrogen ion activity of each unknown, if when the buffer is replaced with unknowns, the following potentials are obtained from?

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.

Can someone me with these questions plz.

Achemist has dissolved a certain substance in water. the chemist knows that more of the substance could be dissolved into the water before it stops dissolving. therefore