Which of the following components of the universe is best described a system of stars, gases and dust held together by gravity

For each of the following types of reactions, write a general reaction formula in the symbolic form—for example, a + b → ab. single-displacement double-displacement synthesis decomposition

If you burn 46.6 g of hydrogen and produce 416 g of water, how much oxygen reacted

15. what volume of cci, (d = 1.6 g/cc) contain6.02 x 1025 cci, molecules (ci = 35.5)(1) 10.5 l(2) 250 ml(3) 9.625 l(4) 1.712 lplz answer with step by step explanation