Astudent must make a buffer solution with a ph of 1.00. determine which weak acid is the best option to make a buffer at the specified ph. formic acid, ka = 1.77 x 10−4, 2.00 m acetic acid, ka = 1.75 x 10−5, 5.00 m sodium bisulfate monohydrate, ka = 1.20 x 10−2, 3.00 m propionic acid, ka =1.34 x 10−5, 3.00 m

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    pb(so₄)₂this element is lead (iv) sulfate. lead is a multivalent ion. but we know that sulfate ions, so₄²⁻, have a charge of -2. in order to have the ratios match up, we need pb⁴⁺ (two times as many pb⁴⁺  than so₄²⁻).the molar mass can be calculated by finding the mass of one mole of this compound. consider the following calculation,  where amu represents the atomic mass unit. the amu for each atom involved in this compound can be found on a periodic table.  molar mass = amu pb + 2(amu s + 4 * amu o)from a periodic table (with masses rounded to the nearest tenth),      amu pb = 207.2 g    amu s =  32.1 g    amu o = 16.0 gtherefore    molar mass =  207.2 + 2(32.1 + 4*16.0) = 399.4 gthe molar mass is therefore 399.4 grams per mol

Astronomers use a number of telescopes sensitive to different parts of the electromagnetic spectrum to study objects in space.