The process of solving 2 should be detailed

Analysis: (1) If there is no 480ml volumetric flask in the laboratory, a 500ml volumetric flask is needed, and the instruments required in the experiment include a tray balance, a medicine spoon, a beaker, a 500ml volumetric flask, a rubber head dropper, and a glass rod;

2) NaCl crystal quality is required for CVM;

3) the weight mass is 10g, then the mass of the free code is, accordingly in Figure 1 mark the position where the left edge of the free code is marked with a vertical line;

When weighing, the rule of "left object and right weight" is adopted;

4) The glass rod plays a stirring role in the dissolving process;

5) It is also necessary to wash the beaker and glass rod with the aim of transferring all the solute to the volumetric flask;

6) When setting the volume, add water to the volumetric flask until the liquid level is close to the scale mark 1 2cm, and use the rubber head dropper to add water to make the concave liquid level of the solution tangent to the scale mark.

Solution: (1) There is no 480ml volumetric flask in the laboratory, so a 500ml volumetric flask is needed, and the instruments required in the experiment include a tray balance, a medicine spoon, a beaker, a 500ml volumetric flask, a rubber head dropper, a glass rod, and the rubber head dropper is used for constant volume, and the glass rod plays the role of stirring and drainage, so the answer is: 500ml volumetric flask; Rubber tip dropper; glass rods;

2) NaCl crystal quality is required for CVM;

So the answer is:;

3) When weighing, the weight quality is: 10g 1 10g, and the quality of the code should be.

So the answer is:;

The weighing of substances with a tray balance should follow the principle of left object and right code, so the NaCl crystal should be placed on the left plate of the balance during the weighing process;

So the answer is: left disk;

4) In the process of dissolving, the glass rod plays a stirring role and can accelerate the dissolution, so the answer is: stirring, accelerating the dissolution;

5) It is also necessary to wash the beaker and glass rod, the purpose is to transfer all the solute to the volumetric flask and reduce the error, so the answer is: ensure that all the solute is transferred to the volumetric flask;

6) When setting the volume, add water to the volumetric flask until the liquid level is close to the scale mark 1 2cm, and use the rubber head dropper to add water to make the solution concave liquid surface tangent to the scale mark, so the answer is: 1 2cm; Rubber tip dropper;

，480ml

Since there is only a container with a capacity of 500ml, the calculated volume should be 500ml.

So n=cv=

Because the molar mass of NaCl is so.

According to the geometric meaning, it is found:

The image of the integrand y= (r 2-x 2) is: the center of the circle at the origin (0,0) is the upper semicircle of the radius of the old perturbation r, since the integral region is (0,r).

So the integral is the area of the first quadrant a=(answer r 2) 4

According to the geometric meaning, it is found:

The image of the integrand y= (r 2-x 2) is: the upper semicircle with the center of the circle at the origin (0,0) radius r, since the integral region is (0,r).

So the integral is the area of the first quadrant a=( r 2) 4

x 2 1,-1 x stake lead 1, the defined domain is [-1,1] sinx 1,2k x (2k+1) where k is an integer.

x+a≤1，-a≤x≤1-a，4、

0 x+a 1, -a x 1-a, at the same time.

0 x-a 1, a x a+1, find the intersection, when a is greater than, the intersection is empty.

When 0 a, the intersection is [a,1-a].

Finding the intersection can be marked with a line loss segment on the coordinate axis of the Kaihao line.