Nitrate is the addition of concentrated sulphuric acid and copper flakes Add concentrated sulphuric acid and copper to the nitrate

Nitrate is the addition of concentrated sulphuric acid and copper flakes Add concentrated sulphuric acid and copper to the nitrate

As I said before, oxidation-reduction reaction, strong first. The strongest oxidant and the strongest reductant, priority reaction. Now the reductant is copper, oxidant has concentrated sulfuric acid, and a hidden -- nitric acid. Why do you say it is hidden, concentrated sulfuric acid provides H+, nitrate provides nitrate, isn't that nitric acid? Ionic compounds in...

The experimental steps of preparing 100mL 3.0mol / L dilute sulfuric acid with 18 mol/L concentrated sulfuric acid are as follows: 1 Calculate the volume of concentrated sulfuric acid used2 Take a certain volume of concentrated sulfuric acid 3 Dissolve 4 Transfer, wash 5 Constant volume, shake well Answer the following questions (1) The volume of concentrated sulfuric acid required is ______, and the specification of measuring cylinder for measuring concentrated sulfuric acid is ______ (Select A.10mL B.20mL C.50mL D.100mL from below) (2) The operation of the third experiment is ______. (3) The operation of step 5 is ______. (4) What is the effect of the following on the concentration of dilute sulfuric acid prepared? (Fill in with large, small and no influence) A. The concentrated sulfuric acid used is placed in a poorly sealed container for a long time ______ B. A small amount of water remains after washing the volumetric flask with distillation ______ C. Used beakers, glass rods not washed ______ D. Liquid concave of solution at constant volume ______.

(1) Set the volume of concentrated sulfuric acid as V,18mol/L×V=0.1L×3.0mol/L, V=0.0167L=16.7mL; the volume of measuring cylinder shall be slightly greater than or equal to the volume of measuring solution, so select B,
Therefore, the answer is:16.7ml;B;
(2) First add 30ml distilled water to the beaker, then slowly pour concentrated sulfuric acid into the beaker along the inner wall of the beaker, and stir it with a glass rod to prevent liquid splashing.
Therefore, the answer is: first add 30ml distilled water into the beaker, then pour concentrated sulfuric acid into the beaker slowly along the inner wall of the beaker, and stir it with a glass rod;
(3) The operation of constant volume shaking: continue to inject distilled water into the volumetric flask until it is 1-2cm away from the scale line, and change the dispensing head dropper to drip into the volumetric flask until the liquid concave is tangent to the scale line. Close the bottle stopper and shake it up in reverse.
Therefore, the solution is as follows: continue to inject distilled water into the volumetric flask until it is 1-2cm away from the scale line, change the dispensing head dropper to drip into the volumetric flask until the liquid concave is tangent to the scale line, plug and tighten the bottle stopper, and invert and shake well;
(4) A. The concentrated sulfuric acid used is placed in a poorly sealed container for a long time. The concentrated sulfuric acid has water absorption, resulting in a small amount of solute and a small concentration of prepared solution;
B. After washing the volumetric flask with distillation, a small amount of water remains, which does not affect the amount of solute substance and the volume of solution, so the amount and concentration of substance for preparing the solution have no effect.
C. The used beakers and glass rods are not washed, resulting in a small amount of solute and a small concentration of prepared solution;
D. Look down at the concave surface of solution at constant volume, resulting in small volume of solution, so the concentration of prepared solution is too large.
The answer is: small; no impact; small; large.