In the compound, 20 g of calcium are combined with 8 g of oxygen. Determine its molecular formula. Anyone help? ​

Which statement describes the appearance of a temperature-vs.-time graph? a horizontal line shows that the temperature increases at a constant rate over time. a vertical line shows that the temperature decreases at a constant rate over time. horizontal lines where the temperature is constant during phase changes connect upward-sloping lines where the temperature increases. horizontal lines where the temperature increases are connected by upward-sloping lines where the temperature is constant for each phase.

About 70 percent of the earth's surface is water-covered, and about 96.5 percent of all earth's water is salt water. identify the watery feature on earth that is made of freshwater rather than salt water. a) bay b) glacier c) ocean d) sea it is not incomplete this is the true question

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?