Food Sterilizer,Food Processing Machinery Parts,Fish Processing Machines

Food Sterilizer,Food Processing Machinery Parts,Fish Processing Machines

Unit 1 enters the chemical world

1. Candle combustion experiment (the product name does not occur when describing the phenomenon)

(1) Flame:

Flame heart, inner flame




Outer flame

The highest temperature

(2) Compare the temperature of each flame layer: Put it in the flame with one match. Phenomenon: Carbonization at both ends; conclusion: The highest temperature of the outer flame


Examine product H2O: Using a dry cold cup cover above the flame, there is water mist in the cup

CO2: Remove the cup, pour in clarifying lime water, oscillation, turbidity (focus)

(4) After extinguishing: there are white smoke (for paraffin vapor), lit white smoke, and the candle is re -ignited. Explain that paraffin vapor burns.

2. Comparison of inhaling air and exhaling gas

Conclusion: Compared with inhaling air, the amount of O2 in the gas in the gas decreases, and the amount of CO2 and H2O increases

(Inhale air is the same as exhaling gas components)

3. Important ways to learn chemistry -scientific inquiry

General steps: ask questions → conjecture and assumptions → design experiment → experimental verification → records and conclusions → reflection and evaluation

Features of chemical learning: pay attention to the nature, changes, changes and phenomena of material;

4. Chemistry experiments (chemistry is a science based on experiments)

1. Common instruments and how to use





IVT tube, cup, bottle, evaporate, cone



Direct heating

The instrument is–

Titter, evaporate dish, burning spoon


Indirect heating

Boil cup, bottle bottle, cone bottle (impuning asbestos net -uniform heating


Heating in solids

Test tube, evaporate

can be use on

Liquid heating

IVT tube, cup, evaporator, bottle, cone -shaped bottle

Not heated

Instrument- ——

Measured tube, funnel, gas collecting cylinder

(2) Increased container -measuring cylinder

When the volume of the liquid is taken, the tube must be stable. The minimum point of the vision and scale and the liquid concave level in the tube remains level.

The measuring cylinder cannot be used for heating and cannot be used as a reaction container. The range of 10 ml is generally read only 0.1 ml.

(3) Illegal measuring device -Tibetan balance (for roughly weighing, generally accurate to 0.1 grams.)

Note: (1) Adjust the zero point first

(2) The position of the weighing object and the weight is “

Left and right code “


The weighing material cannot be placed directly on the tray

When weighing in general drugs, put a piece of paper of the same size and quality in the tray on both sides, and weigh it on the paper. Wet or corrosive drugs (such as sodium hydroxide) are referred to in the stamped glassware (such as small cups and surface dishes).

(4) Crotching with tweezers. When adding the weight,

First add a large quality size, then add a small size with a small quality (big first, then small)

(5) After the weighing,

The travel code should be zero. Put back the 盒 放 放 砝 砝 砝 砝 砝 砝 砝 砝 砝 砝 砝 砝

(4) Heating utensils -alcohol lamp

(1) Pay attention to the use of alcohol lamps “three no”: ①

Do not add alcohol to the burning alcohol lamp

; ②

Use the match to lit the alcohol lamp from the side, do not use the burning alcohol light to directly ignite another alcohol lamp

; ③

The light caps of the alcoholic lamp are turned off and should not be extinguished.

(2) The amount of alcohol in the alcohol lamp should not exceed the volume of alcohol lamps

2/3 should not be less than 1/4

(3) The flames of alcohol lamps are divided into three layers, outer flames, internal flames, and flames.


Heating object

(4) If the alcohol lamp is accidentally turned over when burning, and the alcohol is burned on the experiment,

Destroy the flames with sand or wipes with a wet cloth in time, and cannot be flushed with water.

(5) Cycketer -iron clip, test tube clip

The position of the test tube holding the test tube should be close to the test tube mouth


Essence The long handle of the test tube clip should be pressed on the short handle.

When the test tube is held in the test tube, the test tube clamp should be set up from the bottom of the test tube; the clip part is nearly 1/3 of the tube port;

(6) Instruments that are separated from substances and liquid adding liquid -funnel, long -necked funnel

When filtering, the lower end tube of the funnel should be tightened with the inner wall of the cup to avoid splashing the filtrate.

Long -necked

The lower end pipe port should be inserted below the liquid surface to prevent the generated gas from leaking out of the long -necked

2. Basic operation of chemistry experiments

(1) Access to drugs

1. Storage of medicines:



The medicine is placed in




Fine mouth bottle

China (a small amount of liquid medicine can be placed in a titer), the metal sodium is stored in kerosene, and the white phosphorus is stored in the water (the burning point is too low)

2. The general principles of drug access

① Use the medicine according to the experiment. If the amount is not explained, the minimum amount should be taken. It is advisable to cover the bottom of the test tube to cover the bottom of the test tube, and the liquid should be 1 ~ 2ml.

Do not put more reagents back to the original bottle, nor can it be lost, let alone bring out the laboratory, and should be placed in the specified container.

② “Three No”:

No medicine can be used by hand, tongue tongue, or directly smelling reagents with nose

(If you need to smell the smell of the gas, the application hand is fanned gently at the mouth of the bottle, so that only a small amount of gas enters the nostril)

3. Access to solid medicine

① Powder -like and small granular drugs:

Tablet or V -shaped paper slot

② block and strip medicine:


4. Access to liquid drugs

① The method of pouring the liquid reagent:

Remove the bottle cap and put it on the table (to prevent the drug from being polluted). The label should be facing the heart (to prevent the residual liquid from flowing down the label). Pick up the reagent bottle, close the bottle mouth close to the edge of the test tube, slowly inject the reagent, pour it, cover the bottle cap, label outward, and put back the original place.

② The dripping method of liquid reagents:

Use of dropper: A. First drive out the air in the dropper, then absorb reagents

B. When dripping into the reagent, the dropper should be kept vertically suspended from the mouth of the container.

C. During the use process, always keep the rubber nipples on top to avoid corrosion of the reagent

D. After the dropper is used, wash it with water immediately (except the dropper on the drop of the drop of the drop)

E. Do not reach into the container or contact the wall of the instrument when the tither is used, otherwise it will cause reagent pollution

(2) Connection instrument device and device gas tight inspection

Device gas tightness examination

First immerse one end of the ducts into the water, close the outer wall of the container with your hands, and stop for a while. If there is a bubble of the pipe entrance, the palm of the hand is released, and the water column of the duct mouth rises. Don’t miss the air.

(3) Maternity heating

(1) When heating the solid, the test tube should be tilted slightly. When the test tube is heated, it is evenly heated, and then concentrates heating.

(2) When heating liquid, the volume of the liquid does not exceed 1/3 of the test tube volume. When heating, the test tube and the desktop are about 450 cents. From time to time, the test tube is moved up and down. In order to avoid hurting people, the test tubes should not be cut to themselves or others when heating.

(4) Precautions for filter operation: “

One sticker, two lows, “

“One Post”: Filter paper is close to the inner wall of the funnel

“Two lows”: (1) The edge of the filter paper is lower than the funnel port (2) The liquid surface in the funnel is lower than the edge of the filter paper

“Three Delivery”: (1) The tube of the lower end of the funnel is close to the inner wall of the cup

(2) When drainting with a glass rod, the lower end of the glass rod is gently leaned on the side of the three -layer filter paper

(3) When using a glass rod to drain, the cup tip is close to the middle of the glass rod

After filtering, the possible cause of the filtration fluid is still turbid.

① The cup of the filter liquid is not clean ② When the liquid is poured, the liquid surface is higher than the edge of the filter paper ③ the filter paper is damaged

(5) Evaporation attention point: (1)

During the heating process, use a glass stick to keep stirring

(Function: Accelerate evaporation to prevent droplets splashing due to the high local temperature)

(2) Stop heating when the liquid is close to steaming (or more solids), and use the remaining heat to steam the remaining water

Send it out to avoid splashing solids due to heat.

(3) The hot evaporate dish should be taken with a tongs. If the hot evaporates need to be placed on the experiment immediately, the stone should be put on the stone

Cotton net.

(6) Wash of the instrument:

(1) Pour the waste residue and waste liquid into the waste tank, and the useful material is poured into the specified container

(2) The standard of cleaning the glass instrument: The water attached to the glass instrument will neither gather into water droplets nor the stock flow.

(3) Oil with oil in the glass instrument: First wash with the heat soda (NA2CO3) solution or washing powder, and then rinse with water.

(4) Glass instrument is attached to the alkali, alkaline oxides, and carbonate that is difficult to dissolve in water: first dissolved with dilute hydrochloric acid, and then rinsed with water.

(5) After washing the instrument, it cannot be placed randomly. After the test tube washed, it should be inserted and dried on the test tube frame.




Outer flame


The instrument is–

The instrument is–

The instrument is–







The medicine is placed in

Quality plastic packaging products recommended: plastic eye pharmaceutical packaging container 5ml empty bottles dropper bottle for pharma