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Soils frequently contain large amounts of both iron and aluminum, and the solubility of common solid phases (oxides, hydroxyoxides) of both element vary strongly.  Despite these similarities, “the chemistry of — and concerns about — acid soils is said to be essentially the chemistry of Al”, not Al and Fe; why?

A spherical balloon is inflated with gas at the rate of 200 cubic centimeters per minute. To the nearest tenth of a cm/min, how fast is the radius of the balloon increasing at the instant the radius is 4 centimeters? Hint: V = 4 3 πr 3

Compute the derivative of the function. cot-1(x2+7)

Identify the intervals on which the following function is concave up and concave down. f ( x ) = x 4 – 4 x 3 – 18 x 2 + 9 x – 5

What is the name of the following? PtS[1] KCl [2]   

Based on the successive ionization energies of an unknown element in the table provided, how many valence electrons does the element have?  Successive Ionization energies Number of Electrons Removed Ionization Energies (kJ/mol)  1 600 2 1200 3 3000 4 12,000 5 13,000 6 14,500 7 15,600

A gas mixture in a container has 0.176 mol H2  and 0.631 mol He. The total pressure in the container is 2.91 atm. What is the partial pressure of helium gas? 

Determine if the following interactions are hydrogen bonds?    1 is [1] 2 is [2] 3 is [3]  

What volume in milliliters of 0.0345 M calcium hydroxide (Ca(OH)2) is needed to neutralize 565 mL of 0.0670 M hydrochloric acid (HCl)?

Based on the following hypothetical Lewis structure given X has 6 valence electron and Z has 4 valence electrons, what is the formal charge of on Z?