What is the oxidation number of chromium in K2Cr2O7 ?​

Which sentence best describes the formation of igneous rock? a- lava on the surface dries up and makes arock b_melted rocks cools and forms crystals c_rocks under tremendous heat and pressure d_magma is melted rock underground

In a laboratory, 1.55mg of an organic compound containing carbon, hydrogen, and oxygen is burned for analysis. this combustion resulted in the formation of 1.45mg of carbon dioxide and .89 mg of water. what is the empirical formula for this compound?

In france, grapes are 1.95 euros per kilogram. what is the cost of grapes, in dollars per pound, if the exchange rate is 1.14 dollars/euro? (2.6)