When 4 g of zinc react with 1 g of oxygen, what mass of zinc oxide is produced? To produce copper disulfide, how many grams of
a) sulfur react with 15 g of copper
b) copper react with 10 g of sulphur?

The ratio of oxygen to carbon in carbon dioxide is 2:1. What is the ratio of these elements in carbon monoxide?

Let the ed50 of a recreational drug be defined as the amount required for 50% of a test group to feel high or get a buzz. if the ed50 value of ethanol is 470 mg/kg body mass, what dose would a 70 kg party goer need to quickly consume in order to have a 50% chance of getting a buzz? 235 mg 470 mg 32,900 mg 35,000,000 mg

What do electromagnetic waves carry? how are they produced through which media can they move? where do they transfer energy? what do they not transfer? what do mechanical waves carry? how are they produced? through which media can they move? where do they transfer energy? what do they not transfer?

What is the amount of energy for a photon that has a 125 cm wavelength