Chem exam plz help me

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.

8.98 dm3 of hydrogen gas is collected at 38.8 °c. find the volume the gas will occupy at -39.9 °c if the pressure remains constant.

[ou.03jthe pictures below show the wavelengths and intensities of electromagnetic radiations emitted by three stars, star 1, star 2, and star 3. intensity intensity- intensity- 1000 3500 6000 8500 11000 wavelength (a) star 1 1000 3500 6000 8500 11000 1000 3500 6000 8500 11000 wavelength (a) wavelength (a) star 2 star 3 which of these statements is correct about the color of the three stars? star 2 is white in color o star 2 is yellow in color star 1 and star 3 are yellow in color star 1 and star 3 are white in color