Answer:
2. Given,
Mass of sugar= 40g
Mass of water= 100g
To find :- concentration of sugar in water
Total mass of solution = mass of sugar + mass of water=100g +40g = 140g
percentage of concentration of sugar in solution=
40/140 ×100% =200/7%=28.57% approx
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3. There are 20. mol of Na2CO3
in 10.0L of 2.0M solution
Explanation?--
In our case, we already have the molarity and volume of solution, both of which have good units.
Let's rearrange the equation to solve for the number of moles. We can do this by multiplying by L solution on both sides of the equation. The L solution will cancel out on the right side, leaving the number of moles being equal to the molarity times volume:
Moles of solute
=Lsolution×Molarity
Now we just plug the known values in!
Moles of solute = (10.0 L) (2.0M) = 20. moles
