There are 6.50 g of ²⁴Na after 60 hours. How many grams were in the original sample if its half-life is 15 hours? Your answer must include the math used to arrive at the answer.

The number of neutrons is equal to the atomic number minus the atomic mass. a. true b. false

What will most likely happen in the absence of a cell membrane? a) photosynthesis will not take place. b) the cell will not store food, water, nutrients, and waste. c) energy will not be released during cellular respiration. d) substances will pass in and out of the cell in an uncontrolled manner.

How many moles of bromine are needed to produce 3.23 moles of potassium bromide