Solve the following problem with the correct number of significant figures. 5.31 cm + 8.4 cm + 7.932 cm 2 points
22 cm
21.64 cm
21.642 cm
21.6 cm

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.

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