Answer : The density of an object is, 
Solution : Given,
Mass of an object = 60 g
Volume of an object = 
Formula used :

Now put all the given values in this formula, we get the density of an object.

Therefore, the density of an object is, 
Since we already have the balanced equation, we know that the ratio between
is
respectively.
So then we can set up a proportion to find the number of moles produced when 2.90 moles of Na react completely:

Then we cross multiply and solve for x:


Therefore, we know that when 2.90 moles of Na react completely, there are 1.45 moles of
that are produced.
Instruments
The specific type of instruments depends on the type of laboratory that you're working in: some labs for example use electron microscopes, others use mass spectrophotometers, others use multiplex biochemical analyzers, etc. But very broadly, the specialized tools we use in the laboratory are usually referred to as "instruments"
.3333333 as a repeating decimal
The answer is A. an explanation