Select the correct answer. Which of the following best describes physical science? A. the study of motion B. the study of matter and energy C. the study of Earth's structure and processes D. the study of reactions E. the study of living things ​

Who is better, messi or cristiano, i need this for a chemistry class. asap

Which are forms of frozen water? check all that apply. dew frost hail rain sleet

Ammonium perchlorate nh4clo4 is the solid rocket fuel used by the u.s. space shuttle. it reacts with itself to produce nitrogen gas n2 , chlorine gas cl2 , oxygen gas o2 , water h2o , and a great deal of energy. what mass of nitrogen gas is produced by the reaction of 2.1g of ammonium perchlorate?