Which statement best describes the equation caco3 2hcl → cacl2 co2 h2o? caco3 is a reactant; it is present before the reaction occurs. cacl2 is a reactant; it is present before the reaction occurs. co2 is a reactant because it is most likely a gas. h2o is a reactant because it is most likely a liquid.

Asample of sea water contains 6.28g of sodium chloride per litre of solution. how many milligrams of sodium chloride would be contained in 15.0ml of this solution?

According to the passage, which of these is true about gray water systems? a) gray water systems use plants that require less water. eliminate b) gray water systems require the use of less fossil fuels. c) gray water systems reduce the amount of fresh water used. d) gray water systems reduce the amount water used by shower heads.

An electron moved from a lower energy level to a higher energy level. what most likely happened during the transition? a random amount of light was released. a fixed amount of energy was absorbed. a fixed amount of energy was released. a random amount of light was absorbed.