How many moles of photons are contained in a burst of light that has wavelength 626. nm and contains 18.3 mJ of energy

Which statement describes both homogeneous mixtures and heterogeneous mixtures?

If 3.00 g of titanium metal is reacted with 6.00 g of chlorine gas, cl2, to form 7.7 g of titanium (iv) chloride in a combination reaction, what is the percent yield of the product?

Fill in the coefficients that will balance the following reaction: a0cr2(so4)3 + a1agno3 -> a2cr(no3)3 + a3ag2so4