A gate made of painted iron is beginning to rest in areas where the paint has worn away why is the formation of rust considered a chemical change? A. oxygen in the air combines with the paint, forming a new compound that has the same properties as iron but a different arrangement of atoms.

B. Oxygen in the air combines with the exposed iron, forming a new compound that has properties different from iron.

C. The paint reacts with the iron beneath it and causes rust to form, changing the chemical properties of the iron.

D. The paint reacts with oxygen in the air and causes rust to form, changing the chemical properties of the iron.

The last few miles of the marathon are the most difficult for heather, her hair plastered to her head, sweat clinging to her arms, and her legs already feeling as if they had nothing left, just dead weight. after grabbing a cup of ice water, she feels the ice cubes smash against her nose as she gulps some cool refreshment and keeps on running. in these last few miles, the breeze kicks up and she finally feels some coolness against her skin. drips of sweat, once clinging to her forehead, now spill down, and heather feels more pain as the sweat flows into her eyes. which of the following is the most likely reason why the ice struck heather’s nose when she took a drink? a) water can function as a solvent. b) water can store large amounts of heat. c) water can moderate temperatures through evaporative cooling. d) the density of water decreases when it freezes. e) water has a cohesive nature. sweat remained on heather’s forehead and arms because of the a) high salt content of sweat b) cohesive nature of water c) ability of water to moderate heat d) high evaporative cooling effect of water e) ability of water to act as a solvent

Calculate the ph at the equivalence point for the titration of a solution containing 150.0 mg of ethylamine (c2h5nh2) with 0.1000 m hcl solution. the volume of the solution at the equivalence point is 250.0 ml. kb forethylamine is 4.7 × 10−4 .

How many moles of potassium hydroxide are needed to completely react with 2.94 moles of aluminum sulfate according to the following equation: