Final answer:
To calculate the volume of glycerine needed for a mass of 0.75 lb, we first convert the mass to grams, and then divide by the density of glycerine (1.26 g/ml). This results in a volume of approximately 270.15 ml for the given mass.
Step-by-step explanation:
To find out how many milliliters of glycerine with a density of 1.26 g/ml will have a mass of 0.75 lb, we first need to convert the mass from pounds to grams. The conversion factor is 1 lb = 453.59 g. Therefore, the mass in grams is 0.75 lb × 453.59 g/lb = 340.1925 g.
Next, we use the formula for density, which is density = mass/volume. We can rearrange this to find volume: volume = mass/density. Using the mass in grams that we have just converted and the density of glycerine, the volume in milliliters can be calculated as follows: volume = 340.1925 g ÷ 1.26 g/ml = 270.15 ml (rounded to two decimal places).
Thus, 0.75 lb of glycerine equals approximately 270.15 milliliters when using the known density and conversion factors.