Rust is when a metal turns brown-ish red-ish and that tells you that the metal is old and is no longer useful. we don't want it floating in our bodies because it's rusted metal. hope this helped! :)
Find the molar mass of Fe_2O_3
2Fe = 2*56 = 112
3O = 3* 16 = 48
Molar Mass = 160 grams
moles= given mass / molar mass
moles = 28 / 160
moles = 0.175 <<<< answer
Photochemical smong result from the interaction of pollution in the presence of sunlight. The photochemical smog is result of the <span> chemical reaction in the air between the sunlight, nitrogen oxides and volatile organic compounds.
</span>It is noticed as a brown haze above cities. <span>The negative effects are: production of chlorofluorocarbons (CFCs) increased UV radiation, irritation to the eyes, nose, and throat. </span>
The answer is A. planning a hiking trip
A topographical map would not help studying plant growth over time unless you are looking for a better altitude to plant said plants.
A topographical map would not help studying rainfall for one year unless your location was <em>really</em> so high or low that it affected your weather
And most of all, a topographical map would not be useful for planning a cuise across the Atlantic Ocean because the elevation of the sea is zero!
A topographical map <em>would</em> be useful for planning a hiking trip because there are many factors and details that a hike should have. Which includes height, distance, paths, and elevation.