![](data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" viewBox="0 0 72 71" width="72"></svg>)
Mr. Wang has 30 grams of 95% alcohol. How many grams of water should be added to dilute it to 75% alcohol
Let x g of water be added
（95%*30）/ (30+x)=75%
95%*30=(30+x)*75%
28.5=22.5+0.75x
x=8
Explanation: let's assume that water has x grams
The key to this problem is that the weight of alcohol is constant before and after adding water
So the amount of alcohol before adding water is 95% * 30
The amount of alcohol after adding water is 75% * (30 + x)
The two are equal 95% * 30 = 75% * (30 + x)
So x = 8
Doctor Zhang needs 75% alcohol to see a patient. Now he has 18 kg of 95% alcohol. How many kg of water do you need?
Make a list!
Regardless of the concentration, the solute remains the same, w1v1 = w2v2, so V2 = (w1v1) / W2 = (95% x18) / 75% = 22.8, so the total volume after dilution is 22.8l, but because 95% alcohol is 18L, so water 22.8-18 = 4.8L, by the way, is there any density? If not, the default is 1kg water = 1L, so it is 4.8kg
Doctor Zhang needs 75% alcohol to see a doctor. Now he has 95% alcohol of 18kg. How many kg of water do he need?
18 × 95% △ 75% - 18 = 17.1 △ 0.75-18 = 22.8-18 = 4.8 (kg) a: 4.8 kg of water is needed
14. Doctor Zhang needs 75% alcohol to see a patient. Now he has 18 kg of 95% alcohol. How many kg of water do you need?
It's better to make a list
It takes 4.8kg
Doctor Zhang needs 75% alcohol to treat patients. Now 45% alcohol is 18 kg. How many kg of water do you need
Well, I'll do it
Dr. Zhang needs 80% alcohol to see a patient. Now 95% alcohol is 18 kg. How many kg of water do you need? Thank you
Suppose that the alcohol is M1 kg, the solvent is m kg at the beginning, and the water is m2
m1/m=95%,m1/(m+m2）=80%:m=18
The solution is m = 3.375
Mr. Wang plans to dilute 60 grams of 95% alcohol into 75% alcohol. How many kilograms of water should be added?
The original alcohol is 60 × - 95% = 57 grams
It's still 57 grams
So now it's 57 / 75% = 76 grams
76-60=16
A: 16 grams of water should be added
The health room needs to dilute 800 ml of 95% alcohol solution into 76% alcohol solution for disinfection. How much water should be added
milliliter?
Set to V ml
95％×800＝76％×（800＋V）
V＝152 mL
That is, 152 ml of water is needed
How many kilograms of water is needed to dilute 95% alcohol 150 grams into 75% alcohol after adding some water?
How much water should be evaporated from 40 kg of 12.5% salt water to make 20% salt water?
Please type both questions,
1. 150 * (95% - 75%) / 75% = 40g
2. 40-40 * 12.5% / 20% = 40-25 = 15kg
The ratio of alcohol to water in a certain medicinal alcohol solution is 3:4. (1) how many grams of pure alcohol is needed to prepare 350 grams of this alcohol solution?
(2) there are 12 grams of pure alcohol in the container. When how many grams of water are added, the alcohol solution will be obtained?
1. Alcohol = 350 ÷ (3 + 4) × 3 = 150g
2. Water = 12 △ 3 × 4 = 16 G
RELATED INFORMATIONS
- 1. In a medical alcohol solution, the mass ratio of pure alcohol to water is 3:4. How many grams of pure alcohol are needed to prepare 420g of this medical alcohol solution?
- 2. The disinfectant alcohol in the hospital is made up of pure alcohol and distilled water in a ratio of 3:1. Now there are 600 grams of pure alcohol. How many grams of distilled water do you need to add?
- 3. How is medical alcohol produced? Is it made of anhydrous ethanol and water?
- 4. How to prepare 75% ethanol solution with 95% ethanol
- 5. Observe the mitosis of plant cells and induce chromosome doubling at low temperature Both experiments used plant cells But why is it unnecessary to add Karnaugh's solution to observe mitosis? What's the difference between these two experiments? What should we pay attention to?
- 6. Observe the loading process of plant cell mitosis experiment
- 7. Why do the leaves heated with alcohol bath need to be rinsed with water when doing photosynthesis experiment? Specific reasons
- 8. What is the purpose of alcohol decolorization in photosynthesis? Experiments on Photosynthesis
- 9. High school biology experiment, hydrochloric acid in different experiments, what is the concentration and role
- 10. Why use 75% alcohol instead of 95% alcohol for disinfection?
- 11. How much deionized water does a kilogram of 95% alcohol need to add to make 75% alcohol?
- 12. 500 g of 70% alcohol solution and 300 g of 50% alcohol solution are mixed, and the concentration of alcohol solution is 0______ ．
- 13. In the laboratory, gravity can be measured with a spring dynamometer. The magnitude of gravity is related to what the object is. What is the specific relationship? What is the expression?
- 14. Because of the earth's_______ The force on an object is called gravity____ All objects near the earth are affected_____ What is the force of gravity______ The object under force is______
- 15. What does GM stand for (a unit of weight or a unit of volume) Dosage: 0.1gm/part
- 16. A rectangular cylinder cone of equal base area and volume, the longest of which is Give reasons
- 17. The circumference of the bottom surface of a cylinder is 62.8 cm and the height is 30 cm. If the cylinder is cut into the largest cuboid, what is the volume of the cuboid
- 18. There is a rectangular container and a cylindrical container. The ratio of their bottom area is 5:3. There is 3744 cubic decimeters of water in the rectangular container, and the water depth is 14.4 decimeters The cylinder is empty. Now pour the same amount of water into the rectangular container and the cylindrical container to make the water depth in the two containers equal. This is the water depth of the rectangular container
- 19. How to calculate the volume of pipeline insulation material
- 20. An iron cylinder with a mass of 5 kg, 20 cm high, and a density of 7.8 × 10 ^ 3 kg / m2 Find (1) how much pressure does the table face when it is placed vertically on a horizontal table top? (2) how much pressure does the table face when it is pressed down with Newton's force?