1. A mixture of NaCl and NaBr has a mass of 2.02g and is found to contain 0.72g of Na.What is the mass of NaBr in the mixture?
2. The chloride of an unknown metal is believed to have the formula MCl 3. A 1.891g g sample of the compound is found to contain 3.606×10^-2 mol.Find the atomic mass of M.
3. Phosphorus is obtained primarily from ores containing calcium phosphate.If a particular ore contains 58.5% calcium phosphate, what minimum mass of the ore must be processed to obtain 1.00 kg of phosphorus?
4. Lead is found in Earth's crust as several different lead ores. Suppose a certain rock is composed of 38.0% PbS(galena), 25.0% PbCO 3 (cerussite), and 17.4% PbSO 4(anglesite). The remainder of the rock is composed of substances containing no lead. How much of this rock (in kg must be processed to obtain 4.4 metric tons of lead? (A metric ton is 1000 kg.)
5. A 2.52-g sample of a compound containing only carbon, hydrogen, nitrogen, oxygen, and sulfur was burned in excess O to yield 3.87 g of CO 2 and 0.792 g of H 2 O as the only carbon and hydrogen containing products respectively.
Another sample of the same compound, of mass 4.14 g,yielded 2.31 g of SO 3 as the only sulfur containing product.
A third sample, of mass 5.66 g was burned under different conditions to yield 2.49 g of HNO 3 as the only nitrogen containing product.Calculate the empirical formula of the compound.