Someone help me with these 2 questions please

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.

Main expenses you plan on making payments on a new car too. you want to spend 15% of your monthly net pay on the car payment, insurance, registration, and taxes combined. what is your monthly car allowance? $149.46 $298.91 $448.37 $597.83

How many moles of sulfur dioxide are produced when 4.38 moles of oxygen completely react with iron (iv) sulfide