A sample of gas has oxygen at a pressure of 223 kPa and nitrogen at a pressure of 485 kPa. What is the mole fraction (in decimal form) of oxygen in the sample

They are like other investigations? say there was a murder u have to do blood test and finger prints which run through a lab. 

For lesson: cameras, plant presses, newspaper, paper towels, clip boards, pencils, calculators, field guides, metric measuring tapes, paper, transect squares, colored pencils, ph meters, light meters, computers, etc.for extension: baggies for soil samples collecting, distilled water, hand shovels, beakers, boiled rice, microscopes, well microscope slides or regular microscope slides with cover slips

3is your answer to yuor question