Identify items that can be used to control the boiling when heating liquid in a round bottom flask. Select one or more: Boiling chips or stones check_circle_outline info A rubber stopper or cork A stir bar and stir plate A Bunsen burner

Boiling chips or stones

A rubber stopper or cork

Explanation:

Boiling stones are quite useful in the chemistry  laboratory because they ensure even boiling and prevent the solution from  boiling over. These chips are made to be porous so that they allow solvent vapors to form in the air cavities.

A rubber stopper or cork prevents the boiling liquid from spilling over during boiling by securing the mouth of the flask.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g