Which of the following statements is true? Incandescent light bulbs are almost 100 percent efficient.
Endothermic reactions release heat.
Heat is considered "lost" energy because it cannot be used for work.
An electric drill gains energy in the form of heat and sound.

Which characteristics can be used to differentiate star systems? check all that apply.

What substance has a mass of 9.5g and volume of 2.1cm^3

For the reaction shown, calculate how many moles of no2 form when each of the following completely reacts. 2n2o5(g)→4no2(g)+o2(g) part a 1.0 mol n2o5 express your answer using two significant figures. nothing mol m o l request answer part b 5.4 mol n2o5 express your answer using two significant figures.