(Can someone please help me...im literally done with..) Which answer best completes the following sentence? is an example of physical change while is an example of a chemical change. (1 point) Freezing water, boiling nitrogen Breaking a pencil, rusting of iron Burning wood, dissolving salt in water Bending a piece of aluminum, condensing water vapor

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

Aconcentrated solution of ammonia is 14.8m and has a density of 0.899g/l. what is the concentration of ammonia in this solution in weight percent (%w/w)?

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)