Help out this a quick one

Un cierto gas tiene un volumen de 800ml a 80°c y 600ml a 80°c y 600mmhg de presión. ¿cual será el volumen del gas a condiciones normales? sí el gas es oxígeno, ¿cuál será su peso? y ¿cuántas moléculas están presentes en el sistema?

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

Sarah wants to know where in her garden chamomile would grow the best. she thinks chamomile will grow best in the corner of the garden that gets the most sunlight. to test her hypothesis, she decides to plant several groups of chamomile in her garden as an experiment. which of the following variables will sarah need to measure to know which group of plants grew best? a. the location of the plants b. the type of plants c. the height of the plants d. the amount of water she gives the plants