You think probable to a concentration (and this is expressed in mol/L, g/L etc.).
Brackets around a number mean that the number is of a negative value. Instead of saying -$40 you would express it as ($40).
It is not clear what you mean with "units of power".
2NaCl denotes two fundamental units - each consisting of a sodium cation and a chloride anion - of the ionic compound, sodium chloride. We know, of course, NaCl has a giant ionic structure and does not contain discrete units of NaCl.
You use linear units to express it, such as meters or millimeters, if that's what you mean.
It means express the slope along with its measurement units.
NaCl is sodium chloride.
NaCl has not 2 in the formula unit.
The text in the brackets must be a question.
NaCl is the formula for Sodium Chloride - salt.
It could be the definition of equivalent ratios.
Factorise fully is when brackets are involved in the equation
I'm going to assume that you mean 23.34g of NaCl. 1 mole NaCl = 58.442g NaCl (the atomic weight of Na and Cl in grams) 23.34g NaCl x (1mol NaCl/58.442g NaCl) = 0.3994mol NaCl