1) Answer is: pH = 3,44. c(H₃O⁺) = 3,6·10⁻⁴ M = 3,6·10⁻⁴ mol/L = 0,00036 mol/L. pH = -logc(H₃O⁺). pH = -log(0,00036 mol/L). pH = 3,44. When pH is less than seven (pH<span><), solution is acidic (like this example). </span>When is equal seven (pH = 7), solution is neutral. When pH is greater than seven (pH <span>> 7), solution is basic. </span> 2) Answer is: volume of H₂SO₄ is 5,75 mL. Chemical reaction: H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O. c(H₂SO₄) = 0,2 M = 0,2 mol/L. V(NaOH) = 23 mL = 0,023 L. c(NaOH) = 0,1 M = 0,1 mol/L. n(NaOH) = c(NaOH) · V(NaOH). n(NaOH) = 0,1 mol/L · 0,023 L. n(NaOH) = 0,0023 mol. From chemical reaction: n(H₂SO₄) : n(NaOH) = 1 : 2. n(H₂SO₄) = 0,00115mol. V(H₂SO₄) = n(H₂SO₄) ÷ c(H₂SO₄). V(H₂SO₄) = 0,00115 mol ÷ 0,2 mol/L. V(H₂SO₄) = 0,00575 L = 5,75 mL.
3) c₁(solution) = 0,011 M = 0,011 mol/L. V₁(solution) = 800 mL = 0,8 L. M(methylene blue - C₁₆H₁₈ClN₃S) = 319,85 g/mol. n₁ = c₁ · V₁. n₁ = 0,011 mol/L · 0,8 L. n₁ = 0,0088 mol. m(C₁₆H₁₈ClN₃S) = 0,0088 mol · 319,85 g/mol. m(C₁₆H₁₈ClN₃S) = 2,814 g. m(C₁₆H₁₈ClN₃S) = 2,814 g · 1000mg/g = 2814 mg. V = n ÷ c V₂ = 0,0088 mol ÷ 0,001 mol/L = 8,8 L = 8800 mL. V₃ = 0,0088 mol ÷ 0,00075 mol/L = 11,73 L = 11730 mL.
4) The normality or the equivalent concentration: Cn(KH₂PO₄) = 0,02 N = 0,02 eq/L (<span>equivalent per liter). </span>V(KH₂PO₄) = 0,125 L. number of equivalents of solute = Cn(KH₂PO₄) · V(KH₂PO₄). number of equivalents of solute = 0,02 eq/L · 0,125 L. number of equivalents of solute = 0,0025 eq. equivalent weight = M(KH₂PO₄) ÷ number of equivalents per mole of solute. equivalent weight = 136,1 g/mol ÷ 1 eq/mol. equivalent weight = 136,1 g/eq.
Making repeated separations of the various substances in the pitchblende, Marie and Pierre used the Curie electrometer to identify the most radioactive fractions. They thus discovered that two fractions, one containing mostly bismuth and the other containing mostly barium, were strongly radioactive.
<h3>What was surprising about pitchblende?</h3>
Since it was no longer appropriate to call them “uranic rays,” Marie proposed a new name: “radioactivity.”
Even more surprising, Marie next found that a uranium ore called pitchblende contained two powerfully radioactive new elements: polonium, which she named for her native Poland, and radium.
<h3>Why is radium more radioactive than uranium?</h3>
It is 2.7 million times more radioactive than the same molar amount of natural uranium (mostly uranium-238), due to its proportionally shorter half-life.
Learn more about highly radioactive elements here:
Divide the mass of the compound in grams by the molar mass you just calculated. The answer is the number of moles of that mass of compound. For example, 25 grams of water equals 25/18.016 or 1.39 moles.
Two tectonic plates had the same density and a collision of the plates pushed the advancing plate that contained fossilized marine organisms upward forming the Himalayan mountains and Mount Everest.
coefficient: they balance the chemical equation you have to make sure the number is as small as it can. It is also used to convert different compounds to compounds or quantities to quantities.
