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Relationship between mass fraction For example, the solubility of a solution increases with the increase of temperature, and its mass fraction is p, so its mass fraction decreases after the increase of temperature. I know this. Isn't the mass fraction of solute divided by the mass of solution? Then, when the temperature rises, only the solubility, solute mass and solution mass have not changed (assuming that water does not evaporate), isn't its mass fraction unchanged? How did it get smaller? This friend on the second floor doesn't understand what I mean. Let's mention the specific topic. If you want to change the mass fraction of potassium nitrate saturated solution at a certain temperature, reducing the temperature is also a way. Once the temperature is reduced, the solubility of potassium nitrate solution increases, but no new solute is added, but the maximum solubility of the solution changes. Isn't this process that the solute quality and solution quality haven't changed? How did the mass fraction change? It's not what the friend on the second floor said
Obviously, you don't understand the concept of solubility. (solubility, the mass dissolved when a solid substance reaches saturation in 100g solvent at a certain temperature) the solubility increases, that is, the solute mass increases, the solution mass also increases, and obviously the mass fraction decreases. For example, the solubility of a substance at 10 degrees is 2
At a certain temperature, the solubility of a substance is a g, and the mass fraction of solute in the saturated solution is B%, then the size relationship between a and B is?
a>b
Using the data substitution method,
Suppose the solubility is 10 grams
Then the mass fraction of solute in saturated solution = 10 / 110 = 9.1%
Of course, other data can also be substituted, and the results are the same
It can even carry out mathematical reasoning, which is not necessary
Why is it that the higher the solubility, the greater the mass fraction of the solute in the saturated solution
According to the calculation formula, mass fraction = = s / (s + 100)
From the above formula, the higher the solubility (s), the greater the mass fraction of the solute in the saturated solution
In a saturated solution of a substance at t degrees Celsius, the mass fraction of the solute is a percent, and the solubility is BG. What is the relationship between a and B
a
When the solubility of a solute is s g at a certain temperature, the mass fraction of solute in saturated solution at that temperature () A. Greater than S% B. Equal to S% C. Less than S% D. Unable to judge
Solubility is the saturated solution of S. according to the concept of solubility, s is the mass of solute dissolved when saturation is reached in 100g solvent. Assuming that the solute mass fraction of saturated solution is a%, it means that 100g saturated solution contains Ag solute, that is, some solvents in this solution are less than 100g, the more solvents are at the same temperature, the more solutes are dissolved, so the value of S is greater than the value of A
So choose C
When the mass fraction of solute in KNO3 saturated solution is 20% at a certain temperature, the solubility of KNO3 at this temperature is 25g
At this temperature, the solubility of KNO 3 is XG
x/(x+100) = 20%
The solution is x = 25g
Answer: the solubility of KNO3 at this temperature is 25g
If you do it yourself, please give points
RELATED INFORMATIONS
- 1. When the solubility of a solute is s g at a certain temperature, the mass fraction of solute in saturated solution at that temperature () A. Greater than S% B. Equal to S% C. Less than S% D. Unable to judge
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- 3. （7） 42-5 junior high school chemistry, what is the wrong description of these two particles? Give reasons There are two kinds of particles, the total number of protons in their nucleus is different, but the total number of electrons outside the nucleus is equal. The description of these two kinds of particles is wrong () A. It may be atoms and ions of the same element. B. it may be atoms and ions of different elements C. It cannot be atoms and ions of the same element D. it may be molecules and ions composed of the same element
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- 5. Potassium nitrate solution with mass fraction of 20%, in which solute: solvent: solvent = at 10 ℃, the solubility of a substance is At 10 ℃, the solubility of a substance is 5g. At this temperature, in the substance saturated solution, solute mass: solvent mass: solution mass= Mass fraction of solution=
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- 7. What is meant by a sucrose solution with a mass fraction of 80g solute of 5%
- 8. How many grams of water need to be evaporated to concentrate 100g of sucrose solution with 10% mass fraction into 20% sucrose solution
- 9. 13 g of zinc reacts with 100 g of dilute sulfuric acid to find: (1) the mass of oxygen produced (2) the mass fraction of dilute sulfuric acid
- 10. In 196 g sulfuric acid solution, 32.5 g zinc is added to just complete the reaction. Find the mass of hydrogen produced after the reaction?
- 11. A group measured the mass fraction of calcium carbonate in a limestone. 20g was taken as a nurse sample. 100g of dilute hydrochloric acid with a certain solute mass fraction was added to it
- 12. 25g limestone containing 20% impurities fully reacts with 100g sufficient dilute hydrochloric acid (impurities do not participate in the reaction) Requirements: 1. What is the mass of carbon dioxide generated? 2. How many kilograms of calcium chloride are generated?
- 13. How many grams of carbon dioxide are prepared by fully reacting 100g limestone containing 80% calcium carbonate with 100g dilute hydrochloric acid (assuming that all calcium carbonate react) 1? What is the mass fraction of the solute of the dilute hydrochloric acid
- 14. What is the chemical equation between carbon dioxide and limestone