Scientists sometimes use chemical reactions to reclaim metals from solutions. They do this to reduce toxic waste. Does this mean that the metal has disappeared? Explain your answer.

Which of the following is always a reactant in a combustion reaction? oxygen nitrogen hydrogen carbon

How can a give a full method for the experiment of separating sand from water by filtration? 1-materials 2-steps 3-conclusion also for water and salt separated by the evaporation or distillation process

Give one example of a pure (exact) number and of an estimated (measured) number.