How many moles of copper are needed to react with sulfur to produce 0.25 moles of copper(I) sulfide according to 2Cu+S=Cu2S

True or false, the three major scales used to measure earthquakes are mercalli scale, richter scale and magnitude scale

2pos suppose an object in free fall is dropped from a building. its starting velocity is 0 m/s. ignoring the effects of air resistance, what is the speed (in m/s) of the object after falling 3 seconds? give your answer as a positive decimal without units. answer here

How many grams of magnesium metal will react completely with 8.3 liters of 5.5m hcl? show all work