Any compound that increases the number of hydronium ions when dissolved in water

If 15 drops of ethanol from a medical dropper weight 0.60g, how many drops does it takes from a dropper to dispense 1.0ml of ethanol? the density of ethanol is 0.80g/ml

What is the energy in joules of a mole of photons associated with visible light of wavelength 486 nm?

What are the advantages of using the metric system? designed as a decimal system making conversions simpler more accurate system of measurement has prefixes that correspond to an amount to use with all base units used by the entire scientific community