The radioactive isotope Nickel-63 has a half life of 10 years. How much of a 1000 gram sample
remains after 30 years?

Harvey kept a balloon with a volume of 348 milliliters at 25.0˚c inside a freezer for a night.  when he took it out, its new volume was 322 milliliters, but its pressure was the same.  if the final temperature of the balloon is the same as the freezer’s, what is the temperature of the freezer? the temperature of the freezer is  kelvins.

Apound is approximately 0.45 kilogram. a persons weighs 87 kilograms. what is the persons’s weight, in pounds, when expressed to the correct number of significant figures

Jenny wants to test the electrical conductivity of two substances dissolved in water. she is preparing the containers for the experiment. which factor is most important for her to control?