A 5-g sample of impure magnesium carbonate is reacted with an excess of hydrochloric acid: MgCO3 (s) 1 2HCl (aq) MgCl2 (aq) 1 H2O (l) 1 CO2 ( g) 1250 cm3 of carbon dioxide is collected at rtp. a How many moles of CO2 are produced? b What mass of pure magnesium carbonate would give this volume of carbon dioxide? (Ar : C 5 12, O 5 16, Mg 5 24.) c Calculate the % purity of the 5-g sample.​

The table lists pressure and volume values for a particular gas. which is the best estimate for the value of v at p = 7.0 × 103 pascals?

6. what does the symbol ah stand for? o one calorie given off by a reaction the specific heat of a substance the heat capacity of a substance the heat of reaction for a chemical reaction

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.