Convert given mass of glucose to mol glucose.
Multiply the given mass by the reciprocal of the molar mass.
3color(red)cancel(color(black)("g C"_6"H"_12"O"_6))xx(1"mol C"_6"H"_12"O"_6)/(180color(red)cancel(color(black)("g C"_6"H"_12"O"_6)))="0.017 mol C"_6"H"_12"O"_6"
Determine the volume of the water in liters (L).
Use the density formula to determine the volume of the water.
The density of water is 1.00"g/mL" to three significant figures.
"density"="mass"/"volume"
Solve for volume.
"volume"="mass"/"density"
"volume"=(30color(red)cancel(color(black)("g H"_2"O")))/((1.00color(red)cancel(color(black)("g H"_2"O")))/(1"mL H"_2"O"))="30 mL H"_2"O"
Convert "30 mL H"_2"O" to liters.
"1 L=1000 mL"
30color(red)cancel(color(black)("mL H"_2"O"))xx(1"L H"_2"O")/(1000color(red)cancel(color(black)("mL H"_2"O")))="0.03 L H"_2"O"
Determine molarity.
Molarity, "M", is "moles of solute"/"liters of solution", or "mol/L".
Divide the mol glucose by the volume of the solution in liters.
"M"=(0.017"mol C"_6"H"_12"O"_6)/(0.03"L")="0.6 mol/L C"_6"H"_12"O"_6 (rounded to one significant figure due to "3 g" and "30 mL")