Can some please answer this.

Question

Copper has a density of 2.96 g/cm³. What is the volume of 5.91 g of copper?

Note: You must enter your answer with the proper units. Use a caret (^) to indicate an exponent if necesssary.

Answer 1

Janet J.,

You can do the calculation and answer it!

Two steps: 1) Use "dimensional analysis" (a fancy term for looking at the units of each datum and deciding what mathematical operation, carried out on both the numeric AND units parts of the data, will give you a result in the proper type of units your answer would logically require).

Here, that consists of looking at "g/cm^3" and "g" and deciding what you could do here, such that you will end up with just units of volume ("cm^3"). It's just like doing regular multiplication or division, but using units instead of numbers. Did you decide on doing: "g" / "g/cm^3" = cm^3 ? I hope. Remember, a value in the denominator within a denominator, pops into the numerator, right? If you don't see that, then you need to step back and get some basic-level one-on-one math tutoring, please.

But let's say, you do see that that works. So now, include the numerical values in that total math operation:

(5.91 g Cu) / (2.96 g Cu/cm^3) = 1.99662.... cm^3

2) Round the result appropriately, with respect to significant figures!! Each of the input data have 3 significant digits, so how do you round that number to 3 sig figs?? You round up, 6 is >=5, so 2.00 cm^3.

If this was the first time you encountered "dimensional analysis" as a solution technique, please go back and review it, and make up a few problems of your own, to solve (with different types of units, whatever you are comfortable with). Practice will make you get better and faster at it.

-- Cheers, --Mr. d.