What mass of carbon monoxide (CO) in kg is present in the lower 450 m of air above a section of a city that measures 11 km by 12 on if the concentration of CO is 10 mg/m^3? Please I need this answer by midnight today

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.

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?