18. The density of rubbing alcohol is .789 g/ml. What is the mass of rubbing alcohol in a 500-ml bottle of rubbing alcohol?

The number of   milliliters  of  isopropyl alcohol that are  in   a 400 ml bottle  of this solution  is 280 Ml

Explanation:

% V/V =  volume of  solute/ volume  of  solution  x 100

Let the volume  of solute  be =  y  ml

the volume  of  solution =  400 ml

convert 70%  to fraction = 70/100

by  substituting  the value  in the equation

= y  ml/  400 ml =  70/100

by cross  multiplication

100y =400 x70

100y=  28000

y= 280 ml

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e

m=9

step-by-step explanation: