A sample of water (2 Hydrogens and one oxygen in each molecule)  has a mass of 10.0 grams. What is the number of molecules of water in the 10.0 gram sample (Atomic mass  in amu:  H = 1, O = 16)?

Lawn fetrilizer contains nitrogen, Potash, phosphate, and filler in the ratio 29:3:4:64. What is the mass of nitrogen in one 8kg bag    (if possible, can you please attempt to solve this without using cross multiplication)

The water is safe to drink if the number of cells falls below 10 cells/mL. It is 8 a.m. and you have 100,000 cells/mL with D being 15 minutes. You add the bleach to the tank. At what time can you release the water?  Log Nt = Log N0 – t/D.   D is the time required for a log kill.

6.8 3

The number of bats in a colony is growing exponentially. After 2 years, there were 120 bats. After 5 years, there were 960 bats. If the colony continues to grow at the same rate, how many bats are expected to be in the colony after 8 years? Do not include units in your answer.

The FDA recommends that adults consume 9 x 10 -4 grams of copper per day to help with enzymes that work in your liver.  Calculate the number of atoms of copper you consume each day.

A mass of 41.9 g of an element is known to contain 8.04 x 1023 atoms. What is the atomic mass of the element?