During thermal decomposition of copper carbonate (CuCO 3 ) a student noticed the mass of the copper oxide formed was less than the mass of the copper carbonate at the start of the experiment. Explain, using an equation, why this reaction still follows the law of conservation of mass. (3 marks)

Nebulae are enormous clouds in outer space. they are made mostly of hydrogen gas, helium gas, and dust. some nebulae glow brightly, while others do not. the stars that people see are huge, bright balls of glowing gas. they are made mostly of hydrogen and helium. which statement correctly describes other ways in which nebulae and stars are different? a. stars can form inside a nebula but a nebula can never be produced by any star. b. a star always has a higher density than a nebula. c. stars can never form inside a nebula but a nebula can be produced by any star. d. a nebula always has a higher density than a star.