Drag each label te the correct location on the chart. Sort the questions based on whether they are better answered by an observational study or a controlled experiment.
How effective is a new
mothpaste in reducing
cavities?
How does the daytime
temperature affect the
formation of dew at night?
Which is a better absorber
of heat, an object painted
black or the same object
painted white?
Can plants prepare food
even in artificial light?
Why does a rolling ball slow
down as it moves?
Observational Study
Controlled Experiment

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Explanation:

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