The concentration of 150.0 mL of Na2CO3 is found to be 30.0 ppm. What mass of Na2CO3 is dissolved in the solution if the
density of the solution is 0.750 g/mL?
mass of solute
Use ppm
mass of solution
*106

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .

The answers is a nuclear changes

Ibelieve its because the stove is a cleaner burning fuel