SrCl2(aq) + Na2CO3(aq) --> SrCO3(s) + NaCl(aq) Which coefficient should be placed in front of NaCl to balance this equation?

Large helium-filled balloons are used to lift scientific equipment to high altitudes. what is the pressure inside such a balloon if it starts out at sea level with a temperature of 10.0ºc and rises to an altitude where its volume is twenty times the original volume and its temperature is – 50.0ºc ?

Which of the following is true for a reliable scientific source? it cites logic. it cites opinions. it cites valid data. it cites common sense.

Select the correct answer. which statement best explains the octet rule? a. atoms gain, lose, or share electrons to achieve a full valence shell. b. compounds always consist of eight electrons. c. molecules always consist of eight atoms. d. all atoms require eight electrons to form bonds.