X-5y=30 and 10y=2x+90

According to the diagram, what sources contribute to the phosphorus found in soil? according to the diagram, phosphorus found in soil contributes phosphorus to what other sources?

The lattice enthalpy (formation of ionic solid from ions in the gas phase) for agcl(s) is -916 kj/mol and the hydration enthalpy (dissolution of gaseous ions into water) is -850 kj/mol. how much heat (in joules) is involved in forming 1l of saturated agcl solution (1.8 × 10-4 g / 100 ml water) by dissolving agcl(s)? assume solution volume does not change much upon dissolution. the equations are given below. ag+(g) + cl−(g) æ agcl(s)

Who discovered a pattern to the elements in 1869?