Matter and Change - Mixture
A mixture is a combination of two or more substances in any proportion that do not combine chemically. In this case urea, propylen glycol and crème base.
Answer:
First we calculate the mass of the formulation as it is origynally prepared:
For this we calculate the mass of propylene glycol using its density (1.04 g/ml):
[tex]m=Vx\delta=20mlx1.04\frac{g}{ml}=20.8g[/tex]Now we calculate the total mass:
[tex]m=20g+20.8g+60g=100.8g[/tex]Now we know that 20g of urea are used to prepare 100.8g of the formulation, so we calculate the mass for 18g of the formulation:
[tex]m=18gx\frac{20gurea}{100.8g}=3.57g\text{ }urea[/tex]So the answer is 3.57g of urea.
