Elena makes the table below to determine the number of atoms of each element in the chemical formula 3(NH4)2SO4. What mistake did Elena make?
She should not have multiplied the sulfur atoms by the subscript 4.
She should not have multiplied the nitrogen atoms by the subscript 2.
She should not have multiplied the oxygen atoms by the coefficient 3.
She should not have multiplied the hydrogen atoms by the coefficient 3.

What does the process of natural selection involve

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.

Calculate the number of moles of ethane in 100 grams