What is meant by controlled variable in chemistry

The chemical equation below shows the reaction of sodium (na) and chlorine (cl) to form sodium chloride (nacl). 2na + cl2 → 2nacl in this equation, which of the following is a reactant? i. sodium ii. chlorine iii. sodium chloride

If there are 3.5 moles of koh, how many moles of naoh can be produced? question 1 options: a)3.0 moles naoh b)3.5 moles naoh c)1 moles naoh d)9 moles naoh

Which is true concerning the products and reactants of photosynthesis and cellular respiration? a. the products of photosynthesis are sugars and the reactants of cellular respiration are starches. b. the products of photosynthesis are reactants in cellular respiration. c. oxygen is needed for photosynthesis and is given off in cellular respiration.