Sam wished to investigate how fertilizer run-off affects the growth of algae in freshwater lakes and streams. He set his experiment up in this way. He placed 900 ml of water into each of five 1000 ml glass beakers. To each beaker he added 5 ml of water from an aquarium which contained a large concentration of
algae. The beakers were placed under a grow light which was timed to provide 12 hours of light each day. Liquid fertilizer was added to the beakers in the
following amounts: Beaker A-8 mi fertilizer, Beaker B - 6 ml fertilizer, Beaker C - 4 ml fertilizer, Beaker D-2 mi fertilizer, and Beaker E - no fertilizer. Each
week a random sample from each of the beakers was examined under a microscope to get a count of the number of algal cells present.
What is the independent variable in this experiment?
O hours of daylight
O amount of water
O amount of fertilizer
O number of algal cells

amount of fertaliser--> the independant variable is the one being changed

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.