We will assume that the only reactants are x and y and that the only product is xy.
Based on the law of mass conservation, mass is an isolated system that can neither be created nor destroyed.
Applying this concept to the chemical reaction, we will find that the total mass of the reactants must be equal to the total mass of the products,
therefore:
mass of x + mass of y = mass of xy
12.2 + mass of y = 78.9
mass of y = 78.9 - 12.2 = 66.7 grams
The unit M means that mole/L, So first change the unit of solution volume to L which is 0.25 L. So the mole of solute is 2.5*0.25=0.625 mol.
Hi there! The frequency of a wave is the amount of cycles (or waves) that occur in the given time. So, the answer is D. Normally, the time given is one second, so the frequency unit is Hertz (Hz) most of the time.
Here are some other definitions:
wavelength- the distance from one crest to crest or trough to trough
I hope this helps you! :))