Question

Concentrations

1) calculate the mass of sucrose and the mass of water (in grams) that must be used to prepare 400 g of 50% by mass of sucrose solution. since a solvent is present in greater proportion than the solute in a solution, do these terms still apply at 50% by mass concentration? why?


2) if a wine sample is 12.0% by volume ethanol, how many milliliters of ethanol is present in a bottle containing 500.0 mL of the wine? if other alcoholic drinks have relatively high concentration 35 to 50% (v/v) ethanol, is wine safer to drink before driving? why?


3) a pancake recipe recommends a 65% (v/v) sugar syrup concentration. if you wish to prepare the recipe and you only have 50 g of sugar at home, how will you prepare the syrup? if based on the recipe, one pancake will need 5 mL of the syrup, how many pancakes should you make to use all the syrup you made?


pls help >.

Answer 1

The glucose concentration is measured in mM, the abbreviation for "milliMolar". The molar (M) concentration of a solution is a measure of how much solute (the component of a solution present in lesser amount, often a solid) there is in a given volume of solution. After swirling the flask to dissolve the solid, water is added carefully until the bottom of the meniscus coincides with the calibration mark on the neck of the flash.