number of molecules of sugar in 1 dm cube of 1 molar sugar solution is
Answers
Answer:
First, changing SI units : 1 dm^3 = 1 liter (yes…. it’s it, no “why” here!)
Second, continue to change measurement units : 1 liter = 1 kg
* In fact, this could be explained “why”. Because there’s an equation “d (density) = m (mass) / V (volume)”. “d” of water in research is found out as 1 g/cm^3. So, 1 liter of water seems equal to 1 kilogram of weight
Third, calculating the number of moles (n) of 1 kilogram of water through the equation “m (mass) = n (mol) x M (molar mass). “M” of water is 18. Why?
* Because molecule formula of water is H2O; so, the molar mass of water is the total of atomic mass of all atoms forming it, is equal to “1 (atomic mass of hydrogen) x 2 (there’s 2 hydrogens + 16 (there’s 1 oxygen with atomic mass = 16 ) = 18”.
As the equation “m = n x M” , you can calculate the “n” = m / M = 1000 (g) / 18 = … (mol)
* Why changing kg into g ? Because the standard unit of mass is “gram” in this equation
Finally, calculate the number of molecules in 1 dm^3 water by using Avogadro constant. The Avogadro constant shows that “there’s always about 6.023 x 10^23 atoms/molecules in 1 mol of any substance”.
So, what “…” (mol) above is, multiply for this number “6.023 x 10^23”. You will have an answer of your question !
P.s: the text in “*” is just an explaination for you to more clearly. You can skip it if you have already known