Why would dry cleaners use nonpolar tetrachloroethene to get cheeseburger grease out of your clothes?

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.

If 15 drops of ethanol from a medicine dropper weigh 0.60g, how many drops does it takes from a dropper to dispense 1.0ml of ethanol? density of ethanol is ethanol is 0.80g/ml.

What is the daughter nucleus produced a. when 217(at) undergoes alpha decay? b. when 103(mo) undergoes beta decay? c. when 188(hg) undergoes positron emission?