A rock with a mass of 70 grams is dropped into a graduated cylinder with 30 mL of water in it. The water level rose as shown. Calculate the density of the rock in g/mL.

Find the number of grams of hcl needed to react completely with .50 moles of magnesium.

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it

Astudent pours 10.0 g of salt into a container of water and observes the amount of time it takes for the salt to dissolve. she then repeats the process using the same amounts of salt and water but this time she slowly stirs the mixture while it is dissolving. the student performs the experiment one more time but this time she stirs the mixture rapidly. the dependent variable in this experiment is: time for salt to dissolve speed of stirring amount of water mass of salt