Which instrument, along with a telescope, allows study of the wavelengths of visible light coming from a star?

The graph above shows how the price of cell phones varies with the demand quantity. the equilibrium price for cell phones is where both supply and demand quantities equal $100, 5,000 5,000, $100

What is the empirical formula for c4h8o2

Covalent bonds generally form when the bonded elements have a difference in electronegativity less than 1.5. subtract the electronegativities for the following pairs of elements and predict whether they form a covalent bond. electronegativity difference of c and c: ionic covalent electronegativity difference of mg and cl: ionic covalent