Calculate the wavelength and energy of light that has a frequency of 1.78 x 10^15 Hz

Which statement names the physical property of wood a. wood is softer than coal b. wood does not rust c. wood can rot d. wood can burn

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

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?