An independent-samples t-test provides the following data: Size of sample A is 12, size of sample B is 12; sample variance for sample A is 16.5, sample variance for sample Bis 19.1
What is the pooled variance?

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

When measuring volume, why is it important to use the correct tools and units to attain the greatest accuracy? use specific examples from the lab to support your answer. (5 points)